Depolarization of membrane potentials at the SYNAPTIC MEMBRANES of target neurons during neurotransmission. Excitatory postsynaptic potentials can singly or in summation reach the trigger threshold for ACTION POTENTIALS.
The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.
Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.
Use of electric potential or currents to elicit biological responses.
Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.
The D-enantiomer is a potent and specific antagonist of NMDA glutamate receptors (RECEPTORS, N-METHYL-D-ASPARTATE). The L form is inactive at NMDA receptors but may affect the AP4 (2-amino-4-phosphonobutyrate; APB) excitatory amino acid receptors.
The function of opposing or restraining the excitation of neurons or their target excitable cells.
Projection neurons in the CEREBRAL CORTEX and the HIPPOCAMPUS. Pyramidal cells have a pyramid-shaped soma with the apex and an apical dendrite pointed toward the pial surface and other dendrites and an axon emerging from the base. The axons may have local collaterals but also project outside their cortical region.
Drugs that bind to but do not activate excitatory amino acid receptors, thereby blocking the actions of agonists.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
A persistent increase in synaptic efficacy, usually induced by appropriate activation of the same synapses. The phenomenological properties of long-term potentiation suggest that it may be a cellular mechanism of learning and memory.
A class of ionotropic glutamate receptors characterized by affinity for N-methyl-D-aspartate. NMDA receptors have an allosteric binding site for glycine which must be occupied for the channel to open efficiently and a site within the channel itself to which magnesium ions bind in a voltage-dependent manner. The positive voltage dependence of channel conductance and the high permeability of the conducting channel to calcium ions (as well as to monovalent cations) are important in excitotoxicity and neuronal plasticity.
Most generally any NEURONS which are not motor or sensory. Interneurons may also refer to neurons whose AXONS remain within a particular brain region in contrast to projection neurons, which have axons projecting to other brain regions.
Drugs that bind to but do not activate GABA RECEPTORS, thereby blocking the actions of endogenous GAMMA-AMINOBUTYRIC ACID and GABA RECEPTOR AGONISTS.
A potent excitatory amino acid antagonist with a preference for non-NMDA iontropic receptors. It is used primarily as a research tool.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
Hyperpolarization of membrane potentials at the SYNAPTIC MEMBRANES of target neurons during NEUROTRANSMISSION. They are local changes which diminish responsiveness to excitatory signals.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
Neurons which activate MUSCLE CELLS.
A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.
Extensions of the nerve cell body. They are short and branched and receive stimuli from other NEURONS.
The distal terminations of axons which are specialized for the release of neurotransmitters. Also included are varicosities along the course of axons which have similar specializations and also release transmitters. Presynaptic terminals in both the central and peripheral nervous systems are included.
An isoquinoline alkaloid obtained from Dicentra cucullaria and other plants. It is a competitive antagonist for GABA-A receptors.
The most common inhibitory neurotransmitter in the central nervous system.
A class of ionotropic glutamate receptors characterized by their affinity for the agonist AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid).
The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.
The voltages across pre- or post-SYNAPTIC MEMBRANES.
Drugs that bind to and activate excitatory amino acid receptors.
A noncompetitive antagonist at GABA-A receptors and thus a convulsant. Picrotoxin blocks the GAMMA-AMINOBUTYRIC ACID-activated chloride ionophore. Although it is most often used as a research tool, it has been used as a CNS stimulant and an antidote in poisoning by CNS depressants, especially the barbiturates.
Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.
One of four subsections of the hippocampus described by Lorente de No, located furthest from the DENTATE GYRUS.
Neurotransmitter receptors located on or near presynaptic terminals or varicosities. Presynaptic receptors which bind transmitter molecules released by the terminal itself are termed AUTORECEPTORS.
An amino acid that, as the D-isomer, is the defining agonist for the NMDA receptor subtype of glutamate receptors (RECEPTORS, NMDA).
An aminoperhydroquinazoline poison found mainly in the liver and ovaries of fishes in the order TETRAODONTIFORMES, which are eaten. The toxin causes paresthesia and paralysis through interference with neuromuscular conduction.
The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)
Neural tracts connecting one part of the nervous system with another.
An IBOTENIC ACID homolog and glutamate agonist. The compound is the defining agonist for the AMPA subtype of glutamate receptors (RECEPTORS, AMPA). It has been used as a radionuclide imaging agent but is more commonly used as an experimental tool in cell biological studies.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
A subset of GABA RECEPTORS that signal through their interaction with HETEROTRIMERIC G-PROTEINS.
A GAMMA-AMINOBUTYRIC ACID derivative that is a specific agonist of GABA-B RECEPTORS. It is used in the treatment of MUSCLE SPASTICITY, especially that due to SPINAL CORD INJURIES. Its therapeutic effects result from actions at spinal and supraspinal sites, generally the reduction of excitatory transmission.
Cell surface receptors that bind signalling molecules released by neurons and convert these signals into intracellular changes influencing the behavior of cells. Neurotransmitter is used here in its most general sense, including not only messengers that act to regulate ion channels, but also those which act on second messenger systems and those which may act at a distance from their release sites. Included are receptors for neuromodulators, neuroregulators, neuromediators, and neurohumors, whether or not located at synapses.
Cell membranes associated with synapses. Both presynaptic and postsynaptic membranes are included along with their integral or tightly associated specializations for the release or reception of transmitters.
Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
Drugs that bind to but do not activate GABA-B RECEPTORS thereby blocking the actions of endogenous or exogenous GABA-B RECEPTOR AGONISTS.
Cell-surface proteins that bind glutamate and trigger changes which influence the behavior of cells. Glutamate receptors include ionotropic receptors (AMPA, kainate, and N-methyl-D-aspartate receptors), which directly control ion channels, and metabotropic receptors which act through second messenger systems. Glutamate receptors are the most common mediators of fast excitatory synaptic transmission in the central nervous system. They have also been implicated in the mechanisms of memory and of many diseases.
Clusters of neuronal cell bodies in invertebrates. Invertebrate ganglia may also contain neuronal processes and non-neuronal supporting cells. Many invertebrate ganglia are favorable subjects for research because they have small numbers of functional neuronal types which can be identified from one animal to another.
A superfamily of various freshwater CRUSTACEA, in the infraorder Astacidea, comprising the crayfish. Common genera include Astacus and Procambarus. Crayfish resemble lobsters, but are usually much smaller.
The 8th cranial nerve. The vestibulocochlear nerve has a cochlear part (COCHLEAR NERVE) which is concerned with hearing and a vestibular part (VESTIBULAR NERVE) which mediates the sense of balance and head position. The fibers of the cochlear nerve originate from neurons of the SPIRAL GANGLION and project to the cochlear nuclei (COCHLEAR NUCLEUS). The fibers of the vestibular nerve arise from neurons of Scarpa's ganglion and project to the VESTIBULAR NUCLEI.
GRAY MATTER situated above the GYRUS HIPPOCAMPI. It is composed of three layers. The molecular layer is continuous with the HIPPOCAMPUS in the hippocampal fissure. The granular layer consists of closely arranged spherical or oval neurons, called GRANULE CELLS, whose AXONS pass through the polymorphic layer ending on the DENDRITES of PYRAMIDAL CELLS in the hippocampus.
Substances used for their pharmacological actions on any aspect of neurotransmitter systems. Neurotransmitter agents include agonists, antagonists, degradation inhibitors, uptake inhibitors, depleters, precursors, and modulators of receptor function.
One of two ganglionated neural networks which together form the ENTERIC NERVOUS SYSTEM. The myenteric (Auerbach's) plexus is located between the longitudinal and circular muscle layers of the gut. Its neurons project to the circular muscle, to other myenteric ganglia, to submucosal ganglia, or directly to the epithelium, and play an important role in regulating and patterning gut motility. (From FASEB J 1989;3:127-38)
A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.
Cell surface proteins which bind GAMMA-AMINOBUTYRIC ACID and contain an integral membrane chloride channel. Each receptor is assembled as a pentamer from a pool of at least 19 different possible subunits. The receptors belong to a superfamily that share a common CYSTEINE loop.
Postsynaptic potentials generated from a release of neurotransmitters from a presynaptic nerve terminal in the absence of an ACTION POTENTIAL. They may be m.e.p.p.s (miniature EXCITATORY POSTSYNAPTIC POTENTIALS) or m.i.p.p.s (miniature INHIBITORY POSTSYNAPTIC POTENTIALS).
A pathway of fibers that originates in the lateral part of the ENTORHINAL CORTEX, perforates the SUBICULUM of the HIPPOCAMPUS, and runs into the stratum moleculare of the hippocampus, where these fibers synapse with others that go to the DENTATE GYRUS where the pathway terminates. It is also known as the perforating fasciculus.
Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.
Drugs that bind to but do not activate GABA-A RECEPTORS thereby blocking the actions of endogenous or exogenous GABA-A RECEPTOR AGONISTS.
An alkaloid found in the seeds of STRYCHNOS NUX-VOMICA. It is a competitive antagonist at glycine receptors and thus a convulsant. It has been used as an analeptic, in the treatment of nonketotic hyperglycinemia and sleep apnea, and as a rat poison.
Cell surface proteins that bind glutamate and act through G-proteins to influence second messenger systems. Several types of metabotropic glutamate receptors have been cloned. They differ in pharmacology, distribution, and mechanisms of action.
The largest portion of the CEREBRAL CORTEX in which the NEURONS are arranged in six layers in the mammalian brain: molecular, external granular, external pyramidal, internal granular, internal pyramidal and multiform layers.
Refers to animals in the period of time just after birth.
Clusters of neurons and their processes in the autonomic nervous system. In the autonomic ganglia, the preganglionic fibers from the central nervous system synapse onto the neurons whose axons are the postganglionic fibers innervating target organs. The ganglia also contain intrinsic neurons and supporting cells and preganglionic fibers passing through to other ganglia.
A broad-spectrum excitatory amino acid antagonist used as a research tool.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.
An opisthobranch mollusk of the order Anaspidea. It is used frequently in studies of nervous system development because of its large identifiable neurons. Aplysiatoxin and its derivatives are not biosynthesized by Aplysia, but acquired by ingestion of Lyngbya (seaweed) species.
A technique for maintenance or growth of animal organs in vitro. It refers to three-dimensional cultures of undisaggregated tissue retaining some or all of the histological features of the tissue in vivo. (Freshney, Culture of Animal Cells, 3d ed, p1)
Axons of certain cells in the DENTATE GYRUS. They project to the polymorphic layer of the dentate gyrus and to the proximal dendrites of PYRAMIDAL CELLS of the HIPPOCAMPUS. These mossy fibers should not be confused with mossy fibers that are cerebellar afferents (see NERVE FIBERS).
Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.
Fibers that arise from cells within the cerebral cortex, pass through the medullary pyramid, and descend in the spinal cord. Many authorities say the pyramidal tracts include both the corticospinal and corticobulbar tracts.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)
Elements of limited time intervals, contributing to particular results or situations.
Derivatives of GLUTAMIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure.
A class of ionotropic glutamate receptors characterized by their affinity for KAINIC ACID.
One of two ganglionated neural networks which together form the enteric nervous system. The submucous (Meissner's) plexus is in the connective tissue of the submucosa. Its neurons innervate the epithelium, blood vessels, endocrine cells, other submucosal ganglia, and myenteric ganglia, and play an important role in regulating ion and water transport. (From FASEB J 1989;3:127-38)
Ganglia of the parasympathetic nervous system, including the ciliary, pterygopalatine, submandibular, and otic ganglia in the cranial region and intrinsic (terminal) ganglia associated with target organs in the thorax and abdomen.
A meshlike structure composed of interconnecting nerve cells that are separated at the synaptic junction or joined to one another by cytoplasmic processes. In invertebrates, for example, the nerve net allows nerve impulses to spread over a wide area of the net because synapses can pass information in any direction.
A non-essential amino acid. It is found primarily in gelatin and silk fibroin and used therapeutically as a nutrient. It is also a fast inhibitory neurotransmitter.
The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulchi. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.
The time from the onset of a stimulus until a response is observed.
Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.
An amino acid formed by cyclization of leucine. It has cytostatic, immunosuppressive and antineoplastic activities.
A genus of marine sea slugs in the family Glaucidae, superorder GASTROPODA, found on the Pacific coast of North America. They are used in behavioral and neurological laboratory studies.
A condition characterized by abnormal posturing of the limbs that is associated with injury to the brainstem. This may occur as a clinical manifestation or induced experimentally in animals. The extensor reflexes are exaggerated leading to rigid extension of the limbs accompanied by hyperreflexia and opisthotonus. This condition is usually caused by lesions which occur in the region of the brainstem that lies between the red nuclei and the vestibular nuclei. In contrast, decorticate rigidity is characterized by flexion of the elbows and wrists with extension of the legs and feet. The causative lesion for this condition is located above the red nuclei and usually consists of diffuse cerebral damage. (From Adams et al., Principles of Neurology, 6th ed, p358)
Cell-surface proteins that bind GAMMA-AMINOBUTYRIC ACID with high affinity and trigger changes that influence the behavior of cells. GABA-A receptors control chloride channels formed by the receptor complex itself. They are blocked by bicuculline and usually have modulatory sites sensitive to benzodiazepines and barbiturates. GABA-B receptors act through G-proteins on several effector systems, are insensitive to bicuculline, and have a high affinity for L-baclofen.
Therapeutic introduction of ions of soluble salts into tissues by means of electric current. In medical literature it is commonly used to indicate the process of increasing the penetration of drugs into surface tissues by the application of electric current. It has nothing to do with ION EXCHANGE; AIR IONIZATION nor PHONOPHORESIS, none of which requires current.
Endogenous compounds and drugs that bind to and activate GAMMA-AMINOBUTYRIC ACID receptors (RECEPTORS, GABA).
The 3d cranial nerve. The oculomotor nerve sends motor fibers to the levator muscles of the eyelid and to the superior rectus, inferior rectus, and inferior oblique muscles of the eye. It also sends parasympathetic efferents (via the ciliary ganglion) to the muscles controlling pupillary constriction and accommodation. The motor fibers originate in the oculomotor nuclei of the midbrain.
A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.
The output neurons of the cerebellar cortex.
Ganglia of the sympathetic nervous system including the paravertebral and the prevertebral ganglia. Among these are the sympathetic chain ganglia, the superior, middle, and inferior cervical ganglia, and the aorticorenal, celiac, and stellate ganglia.
Area of the parietal lobe concerned with receiving sensations such as movement, pain, pressure, position, temperature, touch, and vibration. It lies posterior to the central sulcus.
A persistent activity-dependent decrease in synaptic efficacy between NEURONS. It typically occurs following repeated low-frequency afferent stimulation, but it can be induced by other methods. Long-term depression appears to play a role in MEMORY.
Endogenous amino acids released by neurons as excitatory neurotransmitters. Glutamic acid is the most common excitatory neurotransmitter in the brain. Aspartic acid has been regarded as an excitatory transmitter for many years, but the extent of its role as a transmitter is unclear.
Inorganic or organic derivatives of phosphinic acid, H2PO(OH). They include phosphinates and phosphinic acid esters.
(2S-(2 alpha,3 beta,4 beta))-2-Carboxy-4-(1-methylethenyl)-3-pyrrolidineacetic acid. Ascaricide obtained from the red alga Digenea simplex. It is a potent excitatory amino acid agonist at some types of excitatory amino acid receptors and has been used to discriminate among receptor types. Like many excitatory amino acid agonists it can cause neurotoxicity and has been used experimentally for that purpose.
Common name for Carassius auratus, a type of carp (CARPS).
A reflex in which the AFFERENT NEURONS synapse directly on the EFFERENT NEURONS, without any INTERCALATED NEURONS. (Lockard, Desk Reference for Neuroscience, 2nd ed.)
Optical imaging techniques used for recording patterns of electrical activity in tissues by monitoring transmembrane potentials via FLUORESCENCE imaging with voltage-sensitive fluorescent dyes.
The smallest difference which can be discriminated between two stimuli or one which is barely above the threshold.
Nerve structures through which impulses are conducted from a nerve center toward a peripheral site. Such impulses are conducted via efferent neurons (NEURONS, EFFERENT), such as MOTOR NEURONS, autonomic neurons, and hypophyseal neurons.
The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.
The synapse between a neuron and a muscle.
Common name for the only family (Petromyzontidae) of eellike fish in the order Petromyzontiformes. They are jawless but have a sucking mouth with horny teeth.
The part of brain that lies behind the BRAIN STEM in the posterior base of skull (CRANIAL FOSSA, POSTERIOR). It is also known as the "little brain" with convolutions similar to those of CEREBRAL CORTEX, inner white matter, and deep cerebellar nuclei. Its function is to coordinate voluntary movements, maintain balance, and learn motor skills.
Spiny processes on DENDRITES, each of which receives excitatory input from one nerve ending (NERVE ENDINGS). They are commonly found on PURKINJE CELLS and PYRAMIDAL CELLS.
Fishes which generate an electric discharge. The voltage of the discharge varies from weak to strong in various groups of fish. The ELECTRIC ORGAN and electroplax are of prime interest in this group. They occur in more than one family.
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
Paired bundles of NERVE FIBERS entering and leaving the SPINAL CORD at each segment. The dorsal and ventral nerve roots join to form the mixed segmental spinal nerves. The dorsal roots are generally afferent, formed by the central projections of the spinal (dorsal root) ganglia sensory cells, and the ventral roots are efferent, comprising the axons of spinal motor and PREGANGLIONIC AUTONOMIC FIBERS.
A nicotinic cholinergic antagonist often referred to as the prototypical ganglionic blocker. It is poorly absorbed from the gastrointestinal tract and does not cross the blood-brain barrier. It has been used for a variety of therapeutic purposes including hypertension but, like the other ganglionic blockers, it has been replaced by more specific drugs for most purposes, although it is widely used a research tool.
NERVE FIBERS which project from the central nervous system to AUTONOMIC GANGLIA. In the sympathetic division most preganglionic fibers originate with neurons in the intermediolateral column of the SPINAL CORD, exit via ventral roots from upper thoracic through lower lumbar segments, and project to the paravertebral ganglia; there they either terminate in SYNAPSES or continue through the SPLANCHNIC NERVES to the prevertebral ganglia. In the parasympathetic division the fibers originate in neurons of the BRAIN STEM and sacral spinal cord. In both divisions the principal transmitter is ACETYLCHOLINE but peptide cotransmitters may also be released.
An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
Part of the DIENCEPHALON inferior to the caudal end of the dorsal THALAMUS. Includes the lateral geniculate body which relays visual impulses from the OPTIC TRACT to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the AUDITORY CORTEX.
The ability of a substrate to allow the passage of ELECTRONS.
A species of the family Ranidae (true frogs). The only anuran properly referred to by the common name "bullfrog", it is the largest native anuran in North America.
The repeated weak excitation of brain structures, that progressively increases sensitivity to the same stimulation. Over time, this can lower the threshold required to trigger seizures.
Cerebral cortex region on the medial aspect of the PARAHIPPOCAMPAL GYRUS, immediately caudal to the OLFACTORY CORTEX of the uncus. The entorhinal cortex is the origin of the major neural fiber system afferent to the HIPPOCAMPAL FORMATION, the so-called PERFORANT PATHWAY.
An outbred strain of rats developed in 1915 by crossing several Wistar Institute white females with a wild gray male. Inbred strains have been derived from this original outbred strain, including Long-Evans cinnamon rats (RATS, INBRED LEC) and Otsuka-Long-Evans-Tokushima Fatty rats (RATS, INBRED OLETF), which are models for Wilson's disease and non-insulin dependent diabetes mellitus, respectively.
A disorder characterized by recurrent episodes of paroxysmal brain dysfunction due to a sudden, disorderly, and excessive neuronal discharge. Epilepsy classification systems are generally based upon: (1) clinical features of the seizure episodes (e.g., motor seizure), (2) etiology (e.g., post-traumatic), (3) anatomic site of seizure origin (e.g., frontal lobe seizure), (4) tendency to spread to other structures in the brain, and (5) temporal patterns (e.g., nocturnal epilepsy). (From Adams et al., Principles of Neurology, 6th ed, p313)
One of the POTASSIUM CHANNEL BLOCKERS, with secondary effect on calcium currents, which is used mainly as a research tool and to characterize channel subtypes.
A class of drugs that act by selective inhibition of calcium influx through cellular membranes.
GRAY MATTER located in the dorsomedial part of the MEDULLA OBLONGATA associated with the solitary tract. The solitary nucleus receives inputs from most organ systems including the terminations of the facial, glossopharyngeal, and vagus nerves. It is a major coordinator of AUTONOMIC NERVOUS SYSTEM regulation of cardiovascular, respiratory, gustatory, gastrointestinal, and chemoreceptive aspects of HOMEOSTASIS. The solitary nucleus is also notable for the large number of NEUROTRANSMITTERS which are found therein.
One of the two major classes of cholinergic receptors. Nicotinic receptors were originally distinguished by their preference for NICOTINE over MUSCARINE. They are generally divided into muscle-type and neuronal-type (previously ganglionic) based on pharmacology, and subunit composition of the receptors.
Drugs that bind to nicotinic cholinergic receptors (RECEPTORS, NICOTINIC) and block the actions of acetylcholine or cholinergic agonists. Nicotinic antagonists block synaptic transmission at autonomic ganglia, the skeletal neuromuscular junction, and at central nervous system nicotinic synapses.
The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.
Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.
The action of a drug that may affect the activity, metabolism, or toxicity of another drug.
A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
Cells specialized to transduce mechanical stimuli and relay that information centrally in the nervous system. Mechanoreceptor cells include the INNER EAR hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non-neural accessory structures.
Cytoskeleton specialization at the cytoplasmic side of postsynaptic membrane in SYNAPSES. It is involved in neuronal signaling and NEURONAL PLASTICITY and comprised of GLUTAMATE RECEPTORS; scaffolding molecules (e.g., PSD95, PSD93), and other proteins (e.g., CaCMKII).
The relationship between the dose of an administered drug and the response of the organism to the drug.
Substances used for their pharmacological actions on glycinergic systems. Glycinergic agents include agonists, antagonists, degradation or uptake inhibitors, depleters, precursors, and modulators of receptor function.
Set of nerve fibers conducting impulses from olfactory receptors to the cerebral cortex. It includes the OLFACTORY NERVE; OLFACTORY BULB; OLFACTORY TRACT; OLFACTORY TUBERCLE; ANTERIOR PERFORATED SUBSTANCE; and OLFACTORY CORTEX.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
Ovoid body resting on the CRIBRIFORM PLATE of the ethmoid bone where the OLFACTORY NERVE terminates. The olfactory bulb contains several types of nerve cells including the mitral cells, on whose DENDRITES the olfactory nerve synapses, forming the olfactory glomeruli. The accessory olfactory bulb, which receives the projection from the VOMERONASAL ORGAN via the vomeronasal nerve, is also included here.
Cell-surface proteins that bind SEROTONIN and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Drugs used for their actions on any aspect of excitatory amino acid neurotransmitter systems. Included are drugs that act on excitatory amino acid receptors, affect the life cycle of excitatory amino acid transmitters, or affect the survival of neurons using excitatory amino acids.
The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).
A family of hexahydropyridines.
One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.
A branched-chain essential amino acid that has stimulant activity. It promotes muscle growth and tissue repair. It is a precursor in the penicillin biosynthetic pathway.
The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.
Heterocyclic compounds of a ring with SULFUR and two NITROGEN atoms fused to a BENZENE ring. Members inhibit SODIUM-POTASSIUM-CHLORIDE SYMPORTERS and are used as DIURETICS.
Endogenous compounds and drugs that bind to and activate GABA-B RECEPTORS.
A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.
A major class of calcium-activated potassium channels that are found primarily in excitable CELLS. They play important roles in the transmission of ACTION POTENTIALS and generate a long-lasting hyperpolarization known as the slow afterhyperpolarization.
The brain stem nucleus that receives the central input from the cochlear nerve. The cochlear nucleus is located lateral and dorsolateral to the inferior cerebellar peduncles and is functionally divided into dorsal and ventral parts. It is tonotopically organized, performs the first stage of central auditory processing, and projects (directly or indirectly) to higher auditory areas including the superior olivary nuclei, the medial geniculi, the inferior colliculi, and the auditory cortex.
A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the duration of ACTION POTENTIALS. They are used as ANTI-ARRHYTHMIA AGENTS and VASODILATOR AGENTS.
A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
Gelatinous-appearing material in the dorsal horn of the spinal cord, consisting chiefly of Golgi type II neurons and some larger nerve cells.
Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
Physical forces and actions in living things.
An eleven-amino acid neurotransmitter that appears in both the central and peripheral nervous systems. It is involved in transmission of PAIN, causes rapid contractions of the gastrointestinal smooth muscle, and modulates inflammatory and immune responses.
Drugs used to prevent SEIZURES or reduce their severity.
Striped GRAY MATTER and WHITE MATTER consisting of the NEOSTRIATUM and paleostriatum (GLOBUS PALLIDUS). It is located in front of and lateral to the THALAMUS in each cerebral hemisphere. The gray substance is made up of the CAUDATE NUCLEUS and the lentiform nucleus (the latter consisting of the GLOBUS PALLIDUS and PUTAMEN). The WHITE MATTER is the INTERNAL CAPSULE.
Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.
Reflex contraction of a muscle in response to stretching, which stimulates muscle proprioceptors.
The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
An enkephalin analog that selectively binds to the MU OPIOID RECEPTOR. It is used as a model for drug permeability experiments.
Membrane-bound compartments which contain transmitter molecules. Synaptic vesicles are concentrated at presynaptic terminals. They actively sequester transmitter molecules from the cytoplasm. In at least some synapses, transmitter release occurs by fusion of these vesicles with the presynaptic membrane, followed by exocytosis of their contents.
A class of drugs that act by inhibition of sodium influx through cell membranes. Blockade of sodium channels slows the rate and amplitude of initial rapid depolarization, reduces cell excitability, and reduces conduction velocity.
A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.
The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.
Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.
Almond-shaped group of basal nuclei anterior to the INFERIOR HORN OF THE LATERAL VENTRICLE of the TEMPORAL LOBE. The amygdala is part of the limbic system.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
Skeletal muscle structures that function as the MECHANORECEPTORS responsible for the stretch or myotactic reflex (REFLEX, STRETCH). They are composed of a bundle of encapsulated SKELETAL MUSCLE FIBERS, i.e., the intrafusal fibers (nuclear bag 1 fibers, nuclear bag 2 fibers, and nuclear chain fibers) innervated by SENSORY NEURONS.
Drugs that bind to and activate cholinergic receptors.
Neurons in the SPINAL CORD DORSAL HORN whose cell bodies and processes are confined entirely to the CENTRAL NERVOUS SYSTEM. They receive collateral or direct terminations of dorsal root fibers. They send their axons either directly to ANTERIOR HORN CELLS or to the WHITE MATTER ascending and descending longitudinal fibers.
One of the endogenous pentapeptides with morphine-like activity. It differs from LEU-ENKEPHALIN by the amino acid METHIONINE in position 5. Its first four amino acid sequence is identical to the tetrapeptide sequence at the N-terminal of BETA-ENDORPHIN.
A potent noncompetitive antagonist of the NMDA receptor (RECEPTORS, N-METHYL-D-ASPARTATE) used mainly as a research tool. The drug has been considered for the wide variety of neurodegenerative conditions or disorders in which NMDA receptors may play an important role. Its use has been primarily limited to animal and tissue experiments because of its psychotropic effects.
NEURAL PATHWAYS and connections within the CENTRAL NERVOUS SYSTEM, beginning at the hair cells of the ORGAN OF CORTI, continuing along the eighth cranial nerve, and terminating at the AUDITORY CORTEX.
Computer-based representation of physical systems and phenomena such as chemical processes.
Neurons whose primary neurotransmitter is GAMMA-AMINOBUTYRIC ACID.
The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
Central gray matter surrounding the CEREBRAL AQUEDUCT in the MESENCEPHALON. Physiologically it is probably involved in RAGE reactions, the LORDOSIS REFLEX; FEEDING responses, bladder tonus, and pain.
A subsection of the hippocampus, described by Lorente de No, that is located between the HIPPOCAMPUS CA2 FIELD and the DENTATE GYRUS.
The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.
Catalyzes the ATP-dependent PHOSPHORYLATION of GMP to generate GDP and ADP.
Several groups of nuclei in the thalamus that serve as the major relay centers for sensory impulses in the brain.
Clusters of multipolar neurons surrounded by a capsule of loosely organized CONNECTIVE TISSUE located outside the CENTRAL NERVOUS SYSTEM.
Cell surface proteins that bind amino acids and trigger changes which influence the behavior of cells. Glutamate receptors are the most common receptors for fast excitatory synaptic transmission in the vertebrate central nervous system, and GAMMA-AMINOBUTYRIC ACID and glycine receptors are the most common receptors for fast inhibition.
An agonist at two subsets of excitatory amino acid receptors, ionotropic receptors that directly control membrane channels and metabotropic receptors that indirectly mediate calcium mobilization from intracellular stores. The compound is obtained from the seeds and fruit of Quisqualis chinensis.
Endogenous compounds and drugs that bind to and activate GABA-A RECEPTORS.
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.

The functional anatomy of the normal human auditory system: responses to 0.5 and 4.0 kHz tones at varied intensities. (1/5056)

Most functional imaging studies of the auditory system have employed complex stimuli. We used positron emission tomography to map neural responses to 0.5 and 4.0 kHz sine-wave tones presented to the right ear at 30, 50, 70 and 90 dB HL and found activation in a complex neural network of elements traditionally associated with the auditory system as well as non-traditional sites such as the posterior cingulate cortex. Cingulate activity was maximal at low stimulus intensities, suggesting that it may function as a gain control center. In the right temporal lobe, the location of the maximal response varied with the intensity, but not with the frequency of the stimuli. In the left temporal lobe, there was evidence for tonotopic organization: a site lateral to the left primary auditory cortex was activated equally by both tones while a second site in primary auditory cortex was more responsive to the higher frequency. Infratentorial activations were contralateral to the stimulated ear and included the lateral cerebellum, the lateral pontine tegmentum, the midbrain and the medial geniculate. Contrary to predictions based on cochlear membrane mechanics, at each intensity, 4.0 kHz stimuli were more potent activators of the brain than the 0.5 kHz stimuli.  (+info)

Developmental synaptic changes increase the range of integrative capabilities of an identified excitatory neocortical connection. (2/5056)

Excitatory synaptic transmission between pyramidal cells and fast-spiking (FS) interneurons of layer V of the motor cortex was investigated in acute slices by using paired recordings at 30 degrees C combined with morphological analysis. The presynaptic and postsynaptic properties at these identified central synapses were compared between 3- and 5-week-old rats. At these two postnatal developmental stages, unitary EPSCs were mediated by the activation of AMPA receptors with fast kinetics at a holding potential of -72 mV. The amplitude distribution analysis of the EPSCs indicates that, at both stages, pyramidal-FS connections consisted of multiple functional release sites. The apparent quantal size obtained by decreasing the external calcium ([Ca2+]e) varied from 11 to 29 pA near resting membrane potential. In young rats, pairs of presynaptic action potentials elicited unitary synaptic responses that displayed paired-pulse depression at all tested frequencies. In older animals, inputs from different pyramidal cells onto the same FS interneuron had different paired-pulse response characteristics and, at most of these connections, a switch from depression to facilitation occurred when decreasing the rate of presynaptic stimulation. The balance between facilitation and depression endows pyramidal-FS connections from 5-week-old animals with wide integrative capabilities and confers unique functional properties to each synapse.  (+info)

Modulation of long-term synaptic depression in visual cortex by acetylcholine and norepinephrine. (3/5056)

In a slice preparation of rat visual cortex, we discovered that paired-pulse stimulation (PPS) elicits a form of homosynaptic long-term depression (LTD) in the superficial layers when carbachol (CCh) or norepinephrine (NE) is applied concurrently. PPS by itself, or CCh and NE in the absence of synaptic stimulation, produced no lasting change. The LTD induced by PPS in the presence of NE or CCh is of comparable magnitude with that obtained with prolonged low-frequency stimulation (LFS) but requires far fewer stimulation pulses (40 vs 900). The cholinergic facilitation of LTD was blocked by atropine and pirenzepine, suggesting involvement of M1 receptors. The noradrenergic facilitation of LTD was blocked by urapidil and was mimicked by methoxamine, suggesting involvement of alpha1 receptors. beta receptor agonists and antagonists were without effect. Induction of LTD by PPS was inhibited by NMDA receptor blockers (completely in the case of NE; partially in the case of CCh), suggesting that one action of the modulators is to control the gain of NMDA receptor-dependent homosynaptic LTD in visual cortex. We propose that this is a mechanism by which cholinergic and noradrenergic inputs to the neocortex modulate naturally occurring receptive field plasticity.  (+info)

Plasticity of first-order sensory synapses: interactions between homosynaptic long-term potentiation and heterosynaptically evoked dopaminergic potentiation. (4/5056)

Persistent potentiations of the chemical and electrotonic components of the eighth nerve (NVIII) EPSP recorded in vivo in the goldfish reticulospinal neuron, the Mauthner cell, can be evoked by afferent tetanization or local dendritic application of an endogenous transmitter, dopamine (3-hydroxytyramine). These modifications are attributable to the activation of distinct intracellular kinase cascades. Although dopamine-evoked potentiation (DEP) is mediated by the cAMP-dependent protein kinase (PKA), tetanization most likely activates a Ca2+-dependent protein kinase via an increased intracellular Ca2+ concentration. We present evidence that the eighth nerve tetanus that induces LTP does not act by triggering dopamine release, because it is evoked in the presence of a broad spectrum of dopamine antagonists. To test for interactions between these pathways, we applied the potentiating paradigms sequentially. When dopamine was applied first, tetanization produced additional potentiation of the mixed synaptic response, but when the sequence was reversed, DEP was occluded, indicating that the synapses potentiated by the two procedures belong to the same or overlapping populations. Experiments were conducted to determine interactions between the underlying regulatory mechanisms and the level of their convergence. Inhibiting PKA does not impede tetanus-induced LTP, and chelating postsynaptic Ca2+ with BAPTA does not block DEP, indicating that the initial steps of the induction processes are independent. Pharmacological and voltage-clamp analyses indicate that the two pathways converge on functional AMPA/kainate receptors for the chemically mediated EPSP and gap junctions for the electrotonic component or at intermediaries common to both pathways. A cellular model incorporating these interactions is proposed on the basis of differential modulation of synaptic responses via receptor-protein phosphorylation.  (+info)

Activity-dependent metaplasticity of inhibitory and excitatory synaptic transmission in the lamprey spinal cord locomotor network. (5/5056)

Paired intracellular recordings have been used to examine the activity-dependent plasticity and neuromodulator-induced metaplasticity of synaptic inputs from identified inhibitory and excitatory interneurons in the lamprey spinal cord. Trains of spikes at 5-20 Hz were used to mimic the frequency of spiking that occurs in network interneurons during NMDA or brainstem-evoked locomotor activity. Inputs from inhibitory and excitatory interneurons exhibited similar activity-dependent changes, with synaptic depression developing during the spike train. The level of depression reached was greater with lower stimulation frequencies. Significant activity-dependent depression of inputs from excitatory interneurons and inhibitory crossed caudal interneurons, which are central elements in the patterning of network activity, usually developed between the fifth and tenth spikes in the train. Because these interneurons typically fire bursts of up to five spikes during locomotor activity, this activity-dependent plasticity will presumably not contribute to the patterning of network activity. However, in the presence of the neuromodulators substance P and 5-HT, significant activity-dependent metaplasticity of these inputs developed over the first five spikes in the train. Substance P induced significant activity-dependent depression of inhibitory but potentiation of excitatory interneuron inputs, whereas 5-HT induced significant activity-dependent potentiation of both inhibitory and excitatory interneuron inputs. Because these metaplastic effects are consistent with the substance P and 5-HT-induced modulation of the network output, activity-dependent metaplasticity could be a potential mechanism underlying the coordination and modulation of rhythmic network activity.  (+info)

GABAergic excitatory synapses and electrical coupling sustain prolonged discharges in the prey capture neural network of Clione limacina. (6/5056)

Afterdischarges represent a prominent characteristic of the neural network that controls prey capture reactions in the carnivorous mollusc Clione limacina. Their main functional implication is transformation of a brief sensory input from a prey into a lasting prey capture response. The present study, which focuses on the neuronal mechanisms of afterdischarges, demonstrates that a single pair of interneurons [cerebral A interneuron (Cr-Aint)] is responsible for afterdischarge generation in the network. Cr-Aint neurons are electrically coupled to all other neurons in the network and produce slow excitatory synaptic inputs to them. This excitatory transmission is found to be GABAergic, which is demonstrated by the use of GABA antagonists, uptake inhibitors, and double-labeling experiments showing that Cr-Aint neurons are GABA-immunoreactive. The Cr-Aint neurons organize three different pathways in the prey capture network, which provide positive feedback necessary for sustaining prolonged spike activity. The first pathway includes electrical coupling and slow chemical transmission from the Cr-Aint neurons to all other neurons in the network. The second feedback is based on excitatory reciprocal connections between contralateral interneurons. Recurrent excitation via the contralateral cell can sustain prolonged interneuron firing, which then drives the activity of all other cells in the network. The third positive feedback is represented by prominent afterdepolarizing potentials after individual spikes in the Cr-Aint neurons. Afterdepolarizations apparently represent recurrent GABAergic excitatory inputs. It is suggested here that these afterdepolarizing potentials are produced by GABAergic excitatory autapses.  (+info)

Comparative effects of methylmercury on parallel-fiber and climbing-fiber responses of rat cerebellar slices. (7/5056)

The environmental neurotoxicant methylmercury (MeHg) causes profound disruption of cerebellar function. Previous studies have shown that acute exposure to MeHg impairs synaptic transmission in both the peripheral and central nervous systems. However, the effects of MeHg on cerebellar synaptic function have never been examined. In the present study, effects of acute exposure to MeHg on synaptic transmission between parallel fibers or climbing fibers and Purkinje cells were compared in 300- to 350-microm cerebellar slices by using extracellular and intracellular microelectrode-recording techniques. Field potentials of parallel-fiber volleys (PFVs) and the associated postsynaptic responses (PSRs) were recorded in the molecular layer by stimulating the parallel fibers in transverse cerebellar slices. The climbing-fiber responses were also recorded in the molecular layer by stimulating white matter in sagittal cerebellar slices. At 20, 100, and 500 microM, MeHg reduced the amplitude of both PFVs and the associated PSRs to complete block, however, it blocked PSRs more rapidly than PFVs. MeHg also decreased the amplitudes of climbing-fiber responses to complete block. For all responses, an initial increase in amplitude preceded MeHg-induced suppression. Intracellular recordings of excitatory postsynaptic potentials of Purkinje cells were compared before and after MeHg. At 100 microM and 20 microM, MeHg blocked the Na+-dependent, fast somatic spikes and Ca++-dependent, slow dendritic spike bursts. MeHg also hyperpolarized and then depolarized Purkinje cell membranes, suppressed current conduction from parallel fibers or climbing fibers to dendrites of Purkinje cells, and blocked synaptically activated local responses. MeHg switched the pattern of repetitive firing of Purkinje cells generated spontaneously or by depolarizing current injection at Purkinje cell soma from predominantly Na+-dependent, fast somatic spikes to predominantly Ca++-dependent, low amplitude, slow dendritic spike bursts. Thus, acute exposure to MeHg causes a complex pattern of effects on cerebellar synaptic transmission, with apparent actions on both neuronal excitability and chemical synaptic transmission.  (+info)

Receptor mechanisms underlying heterogenic reflexes among the triceps surae muscles of the cat. (8/5056)

The soleus (S), medial gastrocnemius (MG), and lateral gastrocnemius (LG) muscles of the cat are interlinked by rapid spinal reflex pathways. In the decerebrate state, these heterogenic reflexes are either excitatory and length dependent or inhibitory and force dependent. Mechanographic analysis was used to obtain additional evidence that the muscle spindle primary ending and the Golgi tendon organ provide the major contributions to these reflexes, respectively. The tendons of the triceps surae muscles were separated and connected to independent force transducers and servo-controlled torque motors in unanesthetized, decerebrate cats. The muscles were activated as a group using crossed-extension reflexes. Electrical stimulation of the caudal cutaneous sural nerve was used to provide a particularly strong activation of MG and decouple the forces of the triceps surae muscles. During either form of activation, the muscles were stretched either individually or in various combinations to determine the strength and characteristics of autogenic and heterogenic feedback. The corresponding force responses, including both active and passive components, were measured during the changing background tension. During activation of the entire group, the excitatory, heterogenic feedback linking the three muscles was found to be strongest onto LG and weakest onto MG, in agreement with previous results concerning the strengths of heteronymous Ia excitatory postsynaptic potentials among the triceps surae muscles. The inhibition, which is known to affect only the soleus muscle, was dependent on active contractile force and was detected essentially as rapidly as length dependent excitation. The inhibition outlasted the excitation and was blocked by intravenous strychnine. These results indicate that the excitatory and inhibitory effects are dominated by feedback from primary spindle receptors and Golgi tendon organs. The interactions between these two feedback pathways potentially can influence both the mechanical coupling between ankle and knee.  (+info)

From some sources, Ive read that excitatory postsynaptic potentials (EPSPs) decay over time, which would imply that they arent abolished by action potentials. However, other sources seem to indicate the opposite (although I may be misunderstanding them). Plus, the classical leaky-integrate-and-fire neuron model implies that EPSPs are abolished by action potentials (although this could well be a simplification). Does the refractory period of an action potential affect its originating EPSP? Or is it a separate phenomenon?. ...
When depolarizing current was injected only into the cell body of a presynaptic neuron to evoke a burst of APs, the resulting high-frequency train of subthreshold unitary EPSPs (Fig. 1B) failed to trigger changes in the average EPSP amplitudes (Fig. 1D), possibly because EPSP amplitudes decreased rapidly and a sufficiently large postsynaptic depolarization was not reached (3). When the postsynaptic neuron was further depolarized by current injection to produce a burst of APs during the EPSPs, then a persistent increase (,20%) was observed in 8 of 11 connections (Fig. 1, C and D; 94 ± 23% increase) (8, 9).. To establish whether the occurrence of postsynaptic APs during EPSPs was indeed critical for the induction of the increase in EPSP amplitude, a number of control experiments were performed. Pairing of individual postsynaptic APs with EPSPs and without a sustained postsynaptic depolarization (Fig. 2A) induced a persistent increase in EPSP amplitudes (38 ± 9%; n = 21; 20 Hz; Fig. 2B) that was ...
In the hippocampus, activity-dependent changes of synaptic transmission and spike-timing coordination are thought to mediate information processing for the purpose of memory formation. Here we investigated the self-tuning of intrinsic excitability and spiking reliability by CA1 hippocampal pyramidal cells via changes of their GABAergic inhibitory inputs and endocannabinoid signaling. Firing patterns of CA1 place cells, when replayed in vitro, induced an endocannabinoid-dependent transient reduction of spontaneous GABAergic activity, sharing the main features of depolarization-induced suppression of inhibition (DSI), and conditioned a transient improvement of spike-time precision during consecutive burst discharges. When evaluating the consequences of DSI on Excitatory Post-Synaptic Potential (EPSP)-spike coupling, we found that transient reductions of uncorrelated (spontaneous) or correlated (feed-forward) inhibition improved EPSP-Spike coupling probability. The relationship between EPSP-Spike ...
Physiology Test Question - At chemical synapses, opening of ion channels permeable to the following ions can lead to excitatory postsynaptic potentials (EPSPs).
Looking for online definition of Excitatory postsynaptic potentials in the Medical Dictionary? Excitatory postsynaptic potentials explanation free. What is Excitatory postsynaptic potentials? Meaning of Excitatory postsynaptic potentials medical term. What does Excitatory postsynaptic potentials mean?
Heres an old and difficult to access paper (Download: Commins & OMara Psychobiol) of ours from Psychobiology - from the days before all journals were online. Hard to remember those days now…. Psychobiology evolved into Cognitive, Affective, & Behavioral Neuroscience (see past titles here - scroll to bottom).. (This is the longest title on any paper I have ever published…). Commins, S. & OMara, S.M. (2000). Interactions Between Paired-Pulse Facilitation, Low-Frequency Stimulation And Behavioral Stress In The Pathway From Hippocampal Area CA1 To The Subiculum: Dissociation Of Baseline Synaptic Transmission From Paired-Pulse Facilitation And Depression Of The Same Pathway. Psychobiology, 28, 1-11.. Abstract. The interaction between low-frequency stimulation (LFS; 900 stimuli at 10 Hz) of field excitatory postsynaptic potentials (fEPSPs) and paired-pulse facilitation (PPF; 50 & 100msec inter-stimulus intervals) was investigated in the projection from hippocampal area CA1 to the subiculum. We ...
Inhibitory postsynaptic potentials can be inhibited themselves through a signaling process called depolarized-induced suppression of inhibition (DSI) in CA1 pyramidal cells and cerebellar Purkinje cells.[10][11] In a laboratory setting step depolarizations the soma have been used to create DSIs, but it can also be achieved through synaptically induced depolarization of the dendrites. DSIs can be blocked by ionotropic receptor calcium ion channel antagonists on the somata and proximal apical dendrites of CA1 pyramidal cells. Dendritic inhibitory postsynaptic potentials can be severely reduced by DSIs through direct depolarization. Along these lines, inhibitory postsynaptic potentials are useful in the signaling of the olfactory bulb to the olfactory cortex.[12] EPSPs are amplified by persistent sodium ion conductance in external tufted cells. Low-voltage activated calcium ion conductance enhances even larger EPSPs. The hyperpolarization activated nonselective cation conductance decreases EPSP ...
To identify the protein kinases regulating synaptic NMDA receptors, as well as the conditions favoring enhancement of NMDA receptor-mediated excitatory postsynaptic currents (EPSCs) by phosphorylation, we studied the effects of kinase activation and inhibition in hippocampal neurons. Inhibition of c …
The CLP Publishing collects CLP journals and partnered optics and photonics journals, and provides readers an optical publishing platform with global influence. SPIE, OSA, CUP. Chinese Laser Press (CLP), established by Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS) and Chinese Optical Society (COS) in 2009, nowadays publishes eight journals and manages three online platforms.
1. Whole-cell patch-clamp recordings of excitatory postsynaptic currents (EPSCs) were made from guinea pig hippocampal CA1 pyramidal cells. The sensitivity of paired pulse facilitation (PPF) and EPSC variance to changes in synaptic transmission was investigated and the results were compared with the …
TY - JOUR. T1 - Ketamine-mediated afferent-specific presynaptic transmission blocks in low-threshold and sex-specific subpopulation of myelinated ah-type baroreceptor neurons of rats. AU - Wang, Lu Qi. AU - Liu, Sheng Zhi. AU - Wen, Xin. AU - Wu, Di. AU - Yin, Lei. AU - Fan, Yao. AU - Wang, Ye. AU - Chen, Wei Ran. AU - Chen, Pei. AU - Liu, Yang. AU - Lu, Xiao Long. AU - Sun, Hong Li. AU - Shou, Weinian. AU - Qiao, Guo Fen. AU - Li, Bai Yan. PY - 2015/1/1. Y1 - 2015/1/1. N2 - Background: Ketamine enhances autonomic activity, and unmyelinated C-type baroreceptor afferents are more susceptible to be blocked by ketamine than myelinated A-types. However, the presynaptic transmission block in low-threshold and sex-specific myelinated Ah-type baroreceptor neurons (BRNs) is not elucidated. Methods: Action potentials (APs) and excitatory post-synaptic currents (EPSCs) were investigated in BRNs/barosensitive neurons identified by conduction velocity (CV), capsaicin-conjugated with Iberiotoxin-sensitivity ...
The first evidence that glutamatergic synapses in the hippocampus could signal exclusively via NMDA receptors came from analyzing the trial-to-trial amplitude fluctuations of excitatory postsynaptic currents (EPSCs) recorded in CA1 pyramidal neurons in acute rodent brain slices (Kullmann, 1994). The two components of excitatory transmission evoked by stimulating presynaptic axons (Schaffer collaterals of CA3 pyramidal neurons) were isolated by sequentially clamping the postsynaptic membrane potential at a negative value (around -70 mV) to ensure that NMDA receptors were blocked by Mg2+ ions, and then at a positive value (around +40 mV) in the presence of AMPA receptor blockers to reveal NMDA receptor-mediated signaling. If both AMPA and NMDA receptors were present at all synapses, the variability of each component of the postsynaptic signal, expressed as the coefficient of variation (CV), should be approximately equal. This is because CV (the ratio of standard deviation to mean amplitude) is ...
Glutamate activates a number of different receptor-channel complexes, each of which may contribute to generation of excitatory postsynaptic potentials in the mammalian central nervous system. The rapid application of the selective glutamate agonist, quisqualate, activates a large rapidly inactivating current (3 to 8 milliseconds), which is mediated by a neuronal ionic channel with high unitary conductance (35 picosiemens). The current through this channel shows pharmacologic characteristics similar to those observed for the fast excitatory postsynaptic current (EPSC); it reverses near 0 millivolts and shows no significant voltage dependence. The amplitude of the current through this channel is many times larger than that through the other non-NMDA (N-methyl-D-aspartate) channels. These results suggest that this high-conductance quisqualate-activated channel may mediate the fast EPSC in the mammalian central nervous system. ...
Learning is primarily mediated by activity-dependent modifications of synaptic strength within neuronal circuits. We discovered that place fields in hippocampal area CA1 are produced by a synaptic potentiation notably different from Hebbian plasticity. Place fields could be produced in vivo in a single trial by potentiation of input that arrived seconds before and after complex spiking. The potentiated synaptic input was not initially coincident with action potentials or depolarization. This rule, named behavioral time scale synaptic plasticity, abruptly modifies inputs that were neither causal nor close in time to postsynaptic activation. In slices, five pairings of subthreshold presynaptic activity and calcium (Ca(2+)) plateau potentials produced a large potentiation with an asymmetric seconds-long time course. This plasticity efficiently stores entire behavioral sequences within synaptic weights to produce predictive place cell activity.. ...
RESULTS: We found that bath application of DA at a concentration of 100 μM significantly inhibited the amplitude of evoked EPSC. However, the amplitude and frequency of mEPSC were not affected. We also found increased pair pulse facilitation after DA application, indicating DA inhibited excitatory neurotransmission through suppression of release probability at the pre-synaptic terminals. Importantly, DA was also effective in decreasing activity induced upregulation in sEPSCs. Moreover, the DA effects were not affected by either antagonist of dopamine 1 or dopamine 2-like receptors ...
Kainate receptors (KARs) contribute to postsynaptic excitation in only a select subset of neurons. To define the parameters that specify the postsynaptic expression of KARs, I examined the contribution of KARs to EPSCs on hippocampal interneurons in area CAI. Activation of the somatodentritic KARs through bath agonist applications indicated that interneurons in stratum radiatum/lacunosum-moleculare (SRISLM) express KARs both with and without the GluR5 subunit. However, activation of synaptic KARs through stimulus-evoked transmission indicated that only GluR5-containing KARs are targeted to the synapse. Since I was able to pharmacologically silence the synaptic KARs, I was also able to isolate the AMPAR EPSC on these interneurons, and found that AMPARs also contribute to the slowly decaying tail current. Spontaneous EPSCs with a conventional AMPAR component did not have a resolvable contribution of KARs, suggesting that the KARs that contribute to the evoked EPSCs are at a distinct set of synapses.
Synaptic inhibition counterbalances excitation, but it is not known what constitutes optimal inhibition. We previously proposed that perfect balance is achieved when the peak of an excitatory postsynaptic potential (EPSP) is exactly at spike threshold, so that the slightest variation in excitation determines whether a spike is generated. Using simulations, we show that the optimal inhibitory postsynaptic conductance (IPSG) increases in amplitude and decay rate as synaptic excitation increases from 1 to 800 Hz. As further proposed by theory, we show that optimal IPSG parameters can be learned through anti-Hebbian rules ...
At any given cumulative probability level (Fig. 4C, Y), the corresponding mEPSC amplitude in control (Fig. 4C, ACtrl) and that after glutamate dialysis (Fig. 4C, AGlu) could be found. RGlu/Ctrl, calculated as the ratio between AGlu and ACtrl (for methods, see Fig. 4D), decreased as ACtrl increased in 13 (Fig. 4D) of 16 synapses. When data from all 16 synapses were pooled, RGlu/Ctrl clearly decreased as ACtrl increased (for methods, see Fig. 4E), suggesting that glutamate dialysis enhanced larger mEPSCs by a smaller fraction.. As a control, we determined whether large and small mEPSCs are increased by the same fraction when the postsynaptic holding potential changed from −50 to −100 mV. Because of the increase in driving force, the mEPSC amplitude increased by 63 ± 5% (n = 3) (Fig. 5A). The mEPSC amplitude distribution (Fig. 5B) and cumulative probability curve (Fig. 5C) shifted to the right. Similar to calculation of RGlu/Ctrl, we calculated the ratio(R−100 mV/−50 mV) between the mEPSC ...
We have utilized the favorable signal-to-noise ratios provided by whole- cell recording, combined with variance analysis, to determine the pre- or postsynaptic actions of a variety of manipulations on unitary EPSPs evoked by low-intensity stimulation of afferents to CA1 pyramidal neurons in slices of hippocampus. Estimates of quantal content (mcv) were determined by calculating the ratio of the squared average unitary EPSP amplitude (determined from 150-275 responses) to the variance of these responses (M2/sigma 2), while quantal amplitudes (qcv) were estimated by calculating the ratio of the response variance to average EPSP size (sigma 2/M). Estimates of mcv were highly correlated with those determined using the method of failures (mf). With paired stimulation (50 msec interpulse interval) there was a significant facilitation of the second unitary EPSP, accompanied by an increase in mcv, but not qcv, suggesting that this facilitation was of presynaptic origin. Superfusion of hippocampal slices ...
Rookie question here: In slice electrophysiology, if youre recording from a postsynaptic neuron and you perfuse a drug, how do you determine whether the effect of the drug is directly on the postsynaptic neuron from whi…
Paired pulse ratio at the preformed synapse (circles) and the middle axon (squares). The ratio of the ESC amplitude induced by the second stimulus to that
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The mGluR4 (type III) receptor antagonist MPPG specifically prevented the change in paired pulse facilitation (PPF) upon inhibition of glutamate uptake.A shows
Electronic timetravel into the time of true electro beats... Ildaar Spacehealer - Synaptic Transmissions (2014) Psytrance, Techno | Ildaar Spacehealer 320 kbps | MP3 | unmixed | 2014 | 01:2
TY - JOUR. T1 - Angiotensin II depresses glutamate depolarizations and excitatory postsynaptic potentials in locus coeruleus through angiotensin II subtype 2 receptors. AU - Xiong, H.. AU - Marshall, K. C.. PY - 1994/9. Y1 - 1994/9. N2 - A previously reported depression of glutamate responses by angiotensin II was investigated to define the nature of this neuromodulatory effect. Studies were carried out in an in vitro brain slice preparation containing the locus coeruleus, using intracellular recordings, and iontophoretic, micropressure and bath perfusion methods for application of drugs. The angiotensin action was found to be blocked by a non-peptide antagonist specific for the angiotensin type 2 receptor, and not by an antagonist selective for the type 1 receptor. Excitatory postsynaptic potentials mediated primarily by excitatory amino acids were also depressed by angiotensin II. The angiotensin II depressions of glutamate were shown to be strong and highly specific. The low effectiveness of ...
A family of metabotropic glutamate receptors (mGluRs) has been elucidated by molecular cloning. To study the possible modulatory role of mGluRs in synaptic transmission, we tested the effect of a mGluR agonist, (±)-l-aminocyclopentane-trans-l,3-dicarboxylic acid (trans-ACPD), on the excitatory post-synaptic currents (EPSCS) recorded from neurons in thin slices of rat visual cortex, by using the whole-cell patch-clamp method. We found that trans-ACPD) markedly suppressed the evoked EPSCS without affecting the mean amplitude of spontaneous miniature EPSCS. This effect on the evoked EPSCS was blocked by a potassium channel blocker, 4-aminopyridine (4-AP) in a dose-dependent manner We suggest that trans-ACPD presynaptically inhibits EPSCS by a mechanism involving the 4-AP-sensitive channels. ...
TY - JOUR. T1 - Excitatory postsynaptic potentials evoked by ventral root stimulation in neonate rat motoneurons in vitro. AU - Jiang, Z. G.. AU - Shen, E.. AU - Wang, M. Y.. AU - Dun, N. J.. PY - 1991/1/1. Y1 - 1991/1/1. N2 - Intracellular recordings were made from antidromically identified motoneurons in transverse (500 μm) lumbar spinal cord slices of neonatal (12-20 day) rats. Electrical stimulation of ventral rootlets evoked, with or without an antidromic spike or initial segment potential, a depolarizing response (latency, 1-4.2 ms), a hyperpolarizing response (latency, 1.5-3.5 ms), or a combination of two preceding responses in 38, 6, and 8% of motoneurons investigated. The hyperpolarizing response was reversibly eliminated by low Ca2+ (0.25 mM), d-tubocurarine (d-Tc; 10 μM) or strychnine (1 μM), suggesting that this response represents an inhibitory postsynaptic potential (IPSP) mediated by glycine or a related substance released from inhibitory interneurons subsequent to their ...
We show here that synaptic transmission to the medial nucleus of the trapezoid body (MNTB) is mediated principally by excitatory amino acid receptors and has two components. A fast excitatory postsynaptic current (EPSC) is mediated by non-NMDA receptors and a slow EPSC is mediated by NMDA receptors. Each neuron receives a large synaptic input (calyx of Held) which produces an EPSC with a mean peak conductance of 37 nS. The somatic location of this synapse gives good resolution of the EPSC timecourse with the fast EPSC decaying with a time constant of 1.1 ms (at 25 °C). The slow EPSC exhibits a double exponential decay with time constants of 41 ms and 106 ms and is voltage dependent in the presence of extracellular magnesium. Other smaller EPSCS mediated by NMDA and non-NMDA receptors, and a strychnine-sensitive synaptic current, are also present. Although the intrinsic membrane properties of MNTB neurons (Forsythe & Barnes-Davies (Proc. R. Soc. Lond. B 251, 143 (1993)), preceding paper) promote ...
Neural connections require precise organization of the presynaptic and postsynaptic neurons. Neuroligins are transmembrane proteins expressed on the postsynaptic cell that bind to β-neurexins, which are presynaptic transmembrane proteins. Graf et al. report that β-neurexin is present in both excitatory (glutamatergic) and inhibitory (GABAergic) presynaptic neurons of the hippocampus. When these cells were plated with COS cells transfected to express neuroligin-1 or neuroligin-2, the presynaptic specializations that contained synaptic vesicles were induced in both types of axons. Coculture of fibroblasts expressing neurexin-1β with hippocampal neurons triggered the formation of PSD-95-positive or gephyrin-positive postsynaptic clusters in contacting dendrites (PSD-95 is an excitatory postsynaptic organizing protein and gephyrin is an inhibitory postsynaptic organizing protein). In addition, neurexin-1β stimulated clustering of N-methyl-D-aspartate (NMDA)-type glutamate receptor subunits and ...
Neural connections require precise organization of the presynaptic and postsynaptic neurons. Neuroligins are transmembrane proteins expressed on the postsynaptic cell that bind to β-neurexins, which are presynaptic transmembrane proteins. Graf et al. report that β-neurexin is present in both excitatory (glutamatergic) and inhibitory (GABAergic) presynaptic neurons of the hippocampus. When these cells were plated with COS cells transfected to express neuroligin-1 or neuroligin-2, the presynaptic specializations that contained synaptic vesicles were induced in both types of axons. Coculture of fibroblasts expressing neurexin-1β with hippocampal neurons triggered the formation of PSD-95-positive or gephyrin-positive postsynaptic clusters in contacting dendrites (PSD-95 is an excitatory postsynaptic organizing protein and gephyrin is an inhibitory postsynaptic organizing protein). In addition, neurexin-1β stimulated clustering of N-methyl-D-aspartate (NMDA)-type glutamate receptor subunits and ...
Major constituent of the PSD essential for postsynaptic signaling. Inhibitory regulator of the Ras-cAMP pathway. Member of the NMDAR signaling complex in excitatory synapses, it may play a role in NMDAR-dependent control of AMPAR potentiation, AMPAR membrane trafficking and synaptic plasticity. Regulates AMPAR-mediated miniature excitatory postsynaptic currents. Exhibits dual GTPase-activating specificity for Ras and Rap. May be involved in certain forms of brain injury, leading to long-term learning and memory deficits (By similarity).
5-HT1B receptors are widely distributed throughout the central nervous system with the highest concentrations found in the frontal cortex, basal ganglia, striatum, and the hippocampus.[8] The function of the 5-HT1B receptor differs depending upon its location. In the frontal cortex, it is believed to act as a postsynaptic receptor inhibiting the release of dopamine. In the basal ganglia and the striatum, evidence suggests 5-HT signaling acts on an autoreceptor, inhibiting the release of serotonin[9] and decreasing glutamatergic transmission by reducing miniature excitatory postsynaptic potential (mEPSP) frequency,[10] respectively. In the hippocampus, a recent study has demonstrated that activation of postsynaptic 5-HT1B heteroreceptors produces a facilitation in excitatory synaptic transmission which is altered in depression.[11] When the expression of 5-HT1B in human cortex was traced throughout life, significant changes during adolescence were observed, in a way that is strongly correlated ...
The plasticity of inhibitory transmission is expected to play a key role in the modulation of neuronal excitability and network function. Over the last two decades, the investigation of the determinants of inhibitory synaptic plasticity has allowed distinguishing presynaptic and postsynaptic mechanisms. While there has been a remarkable progress in the characterization of presynaptically-expressed plasticity of inhibition, the postsynaptic mechanisms of inhibitory long-term synaptic plasticity only begin to be unraveled. At postsynaptic level, the expression of inhibitory synaptic plasticity involves the rearrangement of the postsynaptic molecular components of the GABAergic synapse, including GABAA receptors, scaffold proteins and structural molecules. This implies a dynamic modulation of receptor intracellular trafficking and receptor surface lateral diffusion, along with regulation of the availability and distribution of scaffold proteins. This Review will focus on the mechanisms of the multifaceted
Graded Potentials - occur in dendrites, cell bodies or axon terminals. Graded potential refers to the post synaptic electrical impulse. Called graded because their size or amplitude is directly proportional to the strength of the triggering event. i.e. a large stimulus leads to the generation of a strong graded response, and a small stimulus leads to the generation of a weak graded response. A depolarising graded potential is known as an excitatory postsynaptic potential (EPSP). A hyperpolarising graded potential is known as an inhibitory postsynaptic potential (IPSP). If graded potentials reaching the axon hillock depolarise the membrane to the threshold voltage, an Action potential is initiated. ...
TITLE AMPA and NMDA receptor with presynaptic short-term plasticity COMMENT AMPA and NMDA receptor conductance using a dual-exponential profile presynaptic short-term plasticity based on Fuhrmann et al. 2002 Implemented by Srikanth Ramaswamy, Blue Brain Project, July 2009 Etay: changed weight to be equal for NMDA and AMPA, gmax accessible in Neuron Tuomo: Changed the data structure so that each instance of this synapse corresponds to a group of synapses. The previous activation time and variables Pv and u are saved for each sub-synapse in this synapse group. Added function setVec() which saves the pointer to these data. Tuomo: In addition to the synapse-wise data, also the past and future activation times are saved. This allows more complicated synapse activation time distributions than stationary Poissonian activation times (e.g., oscillatory Poissonian inputs). Added function setVec2 which sets the vector of IDs of synapses that are activated. This way, whenever the synapse group is ...
Voronin, L. L.; Kuhnt, U.; Gusev, A. G.; Hess, G.: Quantal analysis of long-term potentiation of minimal excitatory postsynaptic potentials in guinea pig hippocampal slices: Binomial approach. Experimental Brain Research 89 (2), pp. 275 - 287 (1992 ...
To investigate short term synaptic plasticity by late somatosensory evoked potentials (SSEP). SSEP (averages of 60 traces): C4-Fz; sup. rad. nerve, n=9), Cz-Fz; N. suralis, n=13). Single stimuli (1S; 0.2ms width) and trains of 3 stimuli (3S, interstimulus interval (ISI) 2-10ms), stimulus repetition rates (SRR) 1Hz, 0.4Hz. N20, N1, N2 (arm nerve) or P40, N1, N2a, N2b (leg nerve) were evaluated. Amplitudes of late SSEP were larger at SRRs of 0.4Hz at 3S versus 1S (p,0.05). At 1Hz SRR, N1 and N2 but not N2a and N2b showed a similar increase. This gain in amplitude after 3S versus 1S was more marked with short ISIs of 2-4ms than with longer ones of 6-10ms. At 1Hz SRR, amplitudes were significantly smaller than at 0.4Hz (p,0.05). The gain in late SSEP amplitudes after 0.4/s 3S versus 1S is presumably due to the summation behaviour of excitatory postsynaptic potentials (EPSP). EPSP summation fades with longer ISI intervals. Therefore, train stimuli may evtl. allow to scan EPSP by using late SSEP. ...
It is well established that neurons employ a variety of mechanism to homeostatically stabilize firing rates in response to bidirectional perturbations of network activity that would deviate firing rates from a defined set point. These mechanisms include regulation of intrinsic excitability (Marder & Goaillard, 2006), shift in the inhibition excitation balance (Maffei et al, 2004; Gonzalez‐Islas & Wenner, 2006), compensatory changes in excitatory synaptic strength (Turrigiano & Nelson, 2004), and modulation of synapse number (Kirov et al, 1999; Wierenga et al, 2006). Which form of homeostatic response is used depends on the developmental stage of the neurons, the form and time of stimulation and can involve both cell‐wide and local adaptations (Turrigiano, 2008; Yu & Goda, 2009). A large body of work has begun to elucidate the molecular mechanisms of adaption to a chronic decrease in network activity, as, for example, induced by the application of tetrodotoxin (Turrigiano, 2012). However, ...
Insect-selective toxin causing rapid but reversible paralysis in crickets. Suppresses the excitatory postsynaptic potentials evoked in lobster neuromuscular synaptic preparations, possibly by blocking the presynaptic calcium channel (Cav). Induces instantaneous reversible paralysis when injected into crickets.
EpSCs are pluripotent and have the capability of being differentiated into all different epithelial cell types. EpSCs are considered a key resource fo...
Simulating it directly using this equation though would be very inefficient, because we would have to sum over all pairs of spikes. That would also be physiologically unrealistic because the neuron cannot remember all its previous spike times. It turns out there is a more efficient and physiologically more plausible way to get the same effect.. We define two new variables \(a_{pre}\) and \(a_{post}\) which are traces of pre- and post-synaptic activity, governed by the differential equations:. When a presynaptic spike occurs, the presynaptic trace is updated and the weight is modified according to the rule:. When a postsynaptic spike occurs:. To see that this formulation is equivalent, you just have to check that the equations sum linearly, and consider two cases: what happens if the presynaptic spike occurs before the postsynaptic spike, and vice versa. Try drawing a picture of it.. Now that we have a formulation that relies only on differential equations and spike events, we can turn that ...
Analysis of rats carrying the microglia gene and Alzheimer risk factor Trem2R47H variant shows increased glutamatergic transmission via supraphysiological TNF-α brain concentrations, linking a microglia pathogenic variant to neuronal dysfunction.
The study investigates the impact that construction of a Severn Barrage in the Severn Estuary, on the west coast of the UK, might have on local wave conditions. Implementation of a barrage will impact on tidal currents and water elevations in the wider region. There is strong tidal modulation of wave conditions under the natural regime and therefore barrage-induced changes to tidal conditions could affect wave modulation in the region. This paper uses Swan, an open source 3rd generation spectral wave model, to investigate the possible impacts of construction of a barrage on tidal modulation of the wave conditions. It is found that current variations, rather than water level variations, are the dominant factor in tidal modulation of wave conditions. Barrage implementation does not substantially change the modulation of the wave period or direction. However, barrage implementation does affect the tidal modulation of wave heights in the area of interest. The tidal modulation of the wave heights is ...
Excitatory synapses release neurotransmitters that excite neurons and synaptic inhibitors release neurotransmitters to inhibit nerve cell excitability synapse.
I just added the column in task manager out of curiosity, and was quite surprised to find the top value at 3,750,000,000 for razer synapseI put the numbers into a calculator and found its generating...
TY - JOUR. T1 - Bidirectional shift of group III metabotropic glutamate receptor-mediated synaptic depression in the epileptic hippocampus. AU - Dammann, Fabian. AU - Kirschstein, Timo. AU - Guli, Xiati. AU - Müller, Steffen. AU - Porath, Katrin. AU - Rohde, Marco. AU - Tokay, Tursonjan. AU - Köhling, Rüdiger. PY - 2018/1/1. Y1 - 2018/1/1. N2 - A common function of group III metabotropic glutamate receptors (mGluRs) located at the presynaptic site of a glutamatergic synapse is synaptic depression. Here, we studied synaptic depression mediated by group III mGluR activation at Schaffer collateral-CA1 (SC-CA1) synapses and associational-commissural-CA3 (AC-CA3) synapses by recording field excitatory postsynaptic potentials in the in vitro brain slice preparation. In order to gauge the impact of synaptic depression in chronically epileptic tissue, we compared rats after pilocarpine-induced status epilepticus (post-SE) with control animals. We observed that synaptic transmission at control AC-CA3 ...
Mossy fiber synapses on CA3 pyramidal cells are conditional detonators that reliably discharge postsynaptic targets. The conditional nature implies that burst activity in dentate gyrus granule cells is required for detonation. Whether single unitary excitatory postsynaptic potentials (EPSPs) trigger spikes in CA3 neurons remains unknown. Mossy fiber synapses exhibit both pronounced short-term facilitation and uniquely large post-tetanic potentiation (PTP). We tested whether PTP could convert mossy fiber synapses from subdetonator into detonator mode, using a recently developed method to selectively and noninvasively stimulate individual presynaptic terminals in rat brain slices. Unitary EPSPs failed to initiate a spike in CA3 neurons under control conditions, but reliably discharged them after induction of presynaptic short-term plasticity. Remarkably, PTP switched mossy fiber synapses into full detonators for tens of seconds. Plasticity-dependent detonation may be critical for efficient ...
TY - JOUR. T1 - Muscarinic depression of excitatory synaptic transmission mediated by the presynaptic M3 receptors in the rat neostriatum. AU - Hsu, Kuei Sen. AU - Huang, Chiung Chun. AU - Gean, Po Wu. PY - 1995/9/8. Y1 - 1995/9/8. N2 - The effect of carbachol on the excitatory synaptic transmission was studied in rat neostriatal neurons using intracellular and whole-cell voltage clamp-recording methods. Depolarizing excitatory postsynaptic potentials (EPSPs) were evoked by cortical stimulation. Superfusion of carbachol (0.01-3 μM) reversibly decreases the EPSP amplitude in a concentration-dependent manner and with an estimated IC50 of 0.3 μM. While, neither the N-methyl-d-aspartate (NMDA, 100 μM)- nor (±)-α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA, 100 μM)-induced response was affected by carbachol (0.1 μM). In addition, the inhibitory effect induced by carbachol at a low concentration of 0.1 μM. was attenuated by 4-diphenylacetoxy-N,N-methyl-piperidine (4-DAMP), a ...
Members of the synapse-associated protein-97 (SAP97) family of scaffold proteins have been implicated as central organizers of synaptic junctions to build macromolecular signaling complexes around specific postsynaptic neurotransmitter receptors. In this regard, SAP97 has been suggested to regulate the synaptic localization of glutamate receptor type 1 subunits of the AMPA-type glutamate receptors. To test this hypothesis directly, we assessed the effects of SAP97 overexpression on surface expression of synaptic AMPA receptors. We find that recombinant SAP97 not only becomes concentrated at synaptic junctions but also leads to an increase in synaptic AMPA receptors, spine enlargement, and an increase in miniature EPSC (mEPSC) frequency, indicating that SAP97 has both postsynaptic and presynaptic effects on synaptic transmission. Synaptic targeting of SAP97, increased surface AMPA receptors, and increased mEPSC frequency are dependent on the presence of specific alternatively spliced sequences in ...
The ribbon synapse, in the absence of light, releases vesicles spontaneously. The single spontaneous excitatory postsynaptic synaptic currents (sEPSCs) can be studied by voltage clamp techniques in ganglion cells (221). It is thought that normal spontaneous release activates AMPA receptors located immediately below the active release zone (Fig. 27). Light stimulation of ON bipolar cells induces release of many vesicles along a single ribbon site and glutamate spillover activates both AMPA and NMDA receptors (Fig. 27). The patch recordings of sEPSCs, under conditions of hyperosmotic Ringer to enhance rates of spontaneous events, reveal large and small as well as fast and slow events (Fig. 27, control). The sEPSCs are mostly eliminated by NBQX, a highly selective antagonist for AMPA and kainate receptors (Fig. 27, NBQX). But small amplitude events still are seen (Fig. 27, NBQX) until the NMDA antagonist D-AP7 is added (Fig. 27, NBQX+DAP7). This indicates that both AMPA and NMDA receptors are ...
excitatory postsynaptic potential (EPSP) will not reach the threshold for action potential initiation. In the brain, however, each neuron forms synapses with many others, and, likewise, each receives synaptic inputs from many others. When action potentials fire simultaneously in several neurons that weakly synapse on a single cell, they may initiate an impulse in that cell even though the synapses are weak. This process is known as summation. On the other hand, a presynaptic neuron releasing an inhibitory neurotransmitter such as ...
A multitude of different serotonin (5-HT) receptor types are expressed in the hippocampus, but the identity of receptors actually mediating the physiological response to endogenous 5-HT has not been determined. We combined pharmacologically induced release of 5-HT with patch-clamp recordings on disinhibited rat CA1 minislices to determine effects of endogenous 5-HT on the excitability of pyramidal neurons and synaptic transmission among them. We found that application of 5-HT releasers, 3,4-methylenedioxy-methamphetamine (MDMA) or p-methylthioamphetamine, at concentrations ranging from 2 to 50 microm, reduced the excitatory synaptic transmission between CA1 pyramidal neurons without altering their basal electrical properties. This effect of MDMA was blocked by the selective 5-HT1B antagonist GR 55562, was dependent on endogenous 5-HT content and was mediated by presynaptically located, pertussis-toxin sensitive mechanisms. We found no other MDMA effects in our preparation, which indicates that ...
2,4-dihydroxyphenylacetylasparaginyl spermine: analog of Joro spider toxin; suppresses the excitatory postsynaptic potentials; structure given in first source
Autor: Borst, J. Gerard G. et al.; Genre: Zeitschriftenartikel; Im Druck veröffentlicht: 1999-11-15; Titel: Depletion of calcium in the synaptic cleft of a calyx-type synapse in the rat brainstem
Rationale: The benzodiazepine lorazepam enhances the potential for inhibitory (GABAA) synapses in the cortex to stabilize postsynaptic, excitatory activity by synchronizing discharge rates at frequencies of around 40 Hz ...
Abstract With the simplicity of the synaptic structure and physiology at neuromuscular junctions (NMJs) of crayfish and the given transmitter being released in quantal packets, a d..
Part of the first shipment I ever received from Tom Bihn was the Synapse (now called the Synapse 19). I bought it alongside the Aeronaut (now called the Aeronaut 45) and the Co-Pilot. The Synapse has been over the last four years my go-to bag. While I take my Smart Alec to work every day because I need extra space in my bag, the Synapse is the bag I grab if Im going out for the day whether it be in the city or out in the country. The reason I always reach for the Synapse is the same reason people always tell me they wouldnt want a Synapse (19) - because its small. Ive bought a lot of big backpacks over the years, and I never want to carry them because theyre too big. Its the size of the Synapse that makes it so useful. Its never too big, and I always manage to fit more into it than I would imagine that I could.. The Synapse has a pretty spacious main compartment with a stretchy inside pocket thats good for keeping things from mushing up against your back. There are two side pockets. I ...
Study Flashcards On Physiology Muscle Weakness synaptic transmission at Quickly memorize the terms, phrases and much more. makes it easy to get the grade you want!
significance of spontaneous release is less clear. Whether receptors on the postsynaptic cell have the ability to … both vesicle release mechanisms activate the same set of receptors, crosstalk would occur between the two modes of … release, indicating a population of postsynaptic receptors is uniquely activated by this mode of vesicle … ...
It is commonly acknowledged that gamma-band oscillations arise from interplay between neural excitation and inhibition; however, the neural mechanisms controlli...
Optically visualized spread of neural activity of area CA1 of rat hippocampal slice preparation evoked by an electrical stimulation. The signal represents the change in fluorescence of voltage sensitive dye (about 5 x 10^-3 deltaF/F at the peak of the response) being incorporated into membranes of neural tissue. Frame rate is 0.7 ms/frame. The field of view is about 2 mm x 1.3 mm. Takashi Tominaga, Ph.D ...
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The effect of in vivo fentanyl treatment on synaptic transmission was studied in the CA1 area of the rat hippocampus. Animals were treated either with saline or fentanyl (4 x 80 mu g/kg, s.c./15 min). Intracellular in vitro ...
Our friends at Razer have launched their Synapse 2.0 beta--and you can have a chance to join by signing up at Synapse 2.
Our friends at Razer have launched their Synapse 2.0 beta--and you can have a chance to join by signing up at Synapse 2.
Needlebeak is preparing a barrage. This is an NPC Ability. A spell from World of Warcraft: Mists of Pandaria. Always up to date with the latest patch.
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I realize that there are mixed views on this, so I hesitate to ask...but has anyone removed the TB label from a Synapse 19? Im not a huge fan of it a
You cannot add Phenomena (Synapse LE 3000 3 Disc Steelbook CD / Blu-Ray Combo) to the cart because the product is out of stock ...
行動神経科学、行動神経内分泌学、分子生物学、その他SYNAPSE Lab. としての活動など. 2015.03.11 HPをリニューアルしました。. 研究室 ...
行動神経科学、行動神経内分泌学、分子生物学、その他SYNAPSE Lab. としての活動など. 2015.03.11 HPをリニューアルしました。. 研究室 ...
ஏதோ பந்து உருண்டு உருண்டு கோட்டுக்கு வெளிய போனா நாலு ரன், அதுவே பறந்து போச்சுன்னா ஆறு ரன், batsman பின்னாடி நட்டு வெச்சுருக்குற மூணு குச்சிய தட்டி விட்டுடுச்சுன்னா அந்த ஆளு out. இப்டி உல்லுல்லாயி மேட்டர் வெச்சே மேட்ச் பாக்குற ஆளு நான். என் வீட்டுகாரரும் நெறைய வாட்டி, long on, long off, mid on, mid off, googly, dhoosra, இப்டின்னால்லாம் என்னன்னு சொல்லி குடுத்துருக்காரு.நானும் ஏதோ 2 marks answers மாதிரி மனப்பாடம் பண்ணி ...
அப்போது வரைக்கும் சைக்கிள் என்று நினைத்தாலே இதமாக மட்டுமே உணர்ந்து கொண்டு இருந்த என்னை, கலவரமாக்கும் அளவுக்கு ஒரு நிகழ்ச்சி நடந்தது அன்று.டைடல் பார்க்கில் ஆபீஸ். வேளச்சேரியில் தங்கி இருந்தேன். ஒரு VIP வீட்டில் இருந்து மூன்றாம் வீடு எங்கள் ஹாஸ்டல்.அதனால் எப்போதும் வெளிச்சமாக செக்யூரிட்டியோடு இருக்கும் தெரு. பொதுவாக நான் நிமிர்ந்து நேராக பார்த்து கொண்டு தான் நடப்பேன். ...
... generates fast excitatory postsynaptic potentials (EPSP). AMPA activates AMPA receptors that are non-selective cationic ... channels allowing the passage of Na+ and K+ and therefore have an equilibrium potential near 0 mV. Ampakine Purves, Dale; ...
In excitatory postsynaptic potentials, an excitatory response is generated. This is caused by an excitatory neurotransmitter, ... This neurotransmitter causes an inhibitory postsynaptic potential in the postsynaptic neuron. This response will cause the ... If a graded potential is strong enough, or if several graded potentials occur in a fast enough frequency, the depolarization is ... In response to stimuli, the sensory receptor initiates sensory transduction by creating graded potentials or action potentials ...
"Gamma-Hydroxybutyrate inhibits excitatory postsynaptic potentials in rat hippocampal slices". European Journal of Pharmacology ... Potential treatment modalities into biochemical and neurological correction should aim to reduce one or both while not ... This disruption has the potential to impair glutamate homeostasis and may lead to uncoupling of the normal balance between ... simultaneously releasing excitatory neurotransmitters onto motor neurons. Because the number and function of GABAB receptors ...
This kind of memory serves as surrogate of the excitatory postsynaptic potential. The model has a threshold N t h {\ ... denotes magnitude of excitatory postsynaptic potential at moment t {\displaystyle t} ; t k {\displaystyle t_{k}} - is the ... The location of the step is controlled by the level of inhibition potential, see Fig. 1. Due to this type of dependence, the H- ... The BN concept originated in 1996 and 1998 papers by A. K. Vidybida, For a generic neuron the stimuli are excitatory impulses. ...
Aghajanian, G. K; Marek, G. J (1 April 1997). "Serotonin Induces Excitatory Postsynaptic Potentials in Apical Dendrites of ... produces an increase in the frequency and amplitude of spontaneous excitatory postsynaptic potentials in layer V pyramidal ... Ronald S. Duman and George K. Aghajanian: Synaptic Dysfunction in Depression: Potential Therapeutic Targets. Science. "George ... Duman, Ronald S.; Aghajanian, George K. (5 October 2012). "Synaptic Dysfunction in Depression: Potential Therapeutic Targets". ...
The AMPA receptor (AMPAR) is the engine that drives excitatory postsynaptic potentials (EPSPs). While some forms of the AMPAR ... the reversal potential of the EPSP current is roughly 0 mV). However, the postsynaptic membrane potential will not change by ... As such, it also spans the electric field generated by the membrane potential. The magnesium binding site within the NMDAR ... This synaptic summation drives the membrane potential toward values that could not be reached with single synaptic stimuli. As ...
These neurons displayed a higher frequency and larger amplitudes of miniature excitatory postsynaptic potentials (mEPSP). Mice ... SynGAP1 is shown to localize at the postsynaptic density on the dendritic spines of excitatory synapses. Cultured neurons of ... Jaffe H, Vinade L, Dosemeci A (August 2004). "Identification of novel phosphorylation sites on postsynaptic density proteins". ...
alpha-1 adrenergic receptor activation, by norepinephrine, decreases glutamatergic excitatory postsynaptic potentials at AMPA ... The field potentials measured for artificially stimulated CDC were eventually much stronger than that of a normal hearing cat. ... An evoked response study of congenitally deaf kittens used local field potentials to measure cortical plasticity in the ... "Preservation of Auditory P300-Like Potentials in Cortical Deafness". PLOS ONE. 7 (1): e29909. Bibcode:2012PLoSO...729909C. doi: ...
In particular, norepinephrine decreases glutamatergic excitatory postsynaptic potentials by the activation of α1-adrenergic ... ISBN 978-0-87893-725-7. Chou EC, Capello SA, Levin RM, Longhurst PA (December 2003). "Excitatory alpha1-adrenergic receptors ...
This causes a depolarization, and results in an excitatory post-synaptic potential. Thus, ACh is excitatory on skeletal muscle ... When a motor neuron generates an action potential, it travels rapidly along the nerve until it reaches the neuromuscular ... Their effect on target cells is usually excitatory. The M2 and M4 subtypes are Gi/Go-coupled; they decrease intracellular ...
An excitatory postsynaptic potential (EPSP) opens the channels, thus generating a LTS. The LTS triggers Na+-dependent action ... such as excitatory postsynaptic potentials (EPSP). LTS were discovered by Rodolfo Llinás and coworkers in the 1980s. ... LTS are often triggered after an inhibitory postsynaptic potential (IPSP) due to the fast recovery of T-type calcium channels ... As with the action potentials that follow them, LTS vary little in amplitude or shape at different holding potentials. This ...
Transduction (biophysics) EPSP(excitatory post-synaptic potential) IPSP (inhibitory post-synaptic potential). Hikosaka, R; ... For the interneurons exhibiting one-way signaling, they would receive an excitatory stimulus, experimentally, and the post- ... The change from a cell that can generate action potentials to solely functioning off of a graded potential is drastic, and may ... These neurons use a graded potential to transmit data as they lack the membrane potential that spiking neurons possess. This ...
Stimulation of aberrant mossy fibre areas increases the excitatory postsynaptic potential response. However, aberrant mossy ... It has been found that GABA reversal potential is depolarising in the subpopulation of the pyramidal cells due to the lack of ... They project into the hilus of the dentate gyrus and stratum lucidum in the CA3 region giving inputs to both excitatory and ... Loss of mossy cells lowers the threshold of action potentials of the granule cells. In certain patients with temporal lobe ...
Kainate receptors likely control a sodium channel that produces excitatory postsynaptic potentials (EPSPs) when glutamate binds ... ISBN 978-0-205-23939-9. Moloney, Mark G. (1998). "Excitatory amino acids". Natural Product Reports. 15 (2): 205-219. doi: ... the principal excitatory neurotransmitter in the central nervous system. Glutamate is produced by the cell's metabolic ... slice preparation to study the physiological effect of excitotoxicity and assess the neuroprotective capabilities of potential ...
Kanda K, Takano K (February 1983). "Effect of tetanus toxin on the excitatory and the inhibitory post-synaptic potentials in ... The action of the A-chain also stops the affected neurons from releasing excitatory transmitters, by degrading the protein ...
Increased NT-3/trkC binding results in larger monosynaptic excitatory postsynaptic potentials (EPSPs) and reduced polysynaptic ... reducing the size of monosynaptic excitatory postsynaptic potentials (EPSPs) and increasing polysynaptic signaling. In the ... In other cases, such as neuroblastoma Trk A acts as a promising prognostic indicator as it has the potential to induce terminal ... Aloe L, Rocco ML, Bianchi P, Manni L (November 2012). "Nerve growth factor: from the early discoveries to the potential ...
"The involvement of adenosine neuromodulation in pentobarbital-induced field excitatory postsynaptic potentials depression in ... Boissard CG, Gribkoff VK (1993). "The effects of the adenosine reuptake inhibitor soluflazine on synaptic potentials and ... on extracellular purines and excitatory amino acids in CA1 of rat hippocampus during transient ischaemia". Br J Pharmacol. 100 ... barbiturates and propofol of excitatory synaptic transmissions mediated by adenosine neuromodulation]". Masui. 55 (6): 684-691 ...
Excitatory and inhibitory synaptic transmission is realized mostly by excitatory postsynaptic potentials (EPSPs), and ... strongly on the relative timing of the onset of the excitatory postsynaptic potential and the postsynaptic action potential. ... potentials at the post-synaptic membrane will summate in the cell body). Later models also provided for excitatory and ... One principle by which neurons work is neural summation - potentials at the postsynaptic membrane will sum up in the cell body ...
Receptors in groups II and III reduce the activity of postsynaptic potentials, both excitatory and inhibitory, in the cortex. ... These receptors are involved in presynaptic inhibition, and do not appear to affect postsynaptic membrane potential by ... but they also increase inhibitory postsynaptic potentials, or IPSPs. They can also inhibit glutamate release and can modulate ... For example, one study found that Group I mGluRs are located mostly on postsynaptic parts of cells, while groups II and III are ...
Electrical stimuli to the auditory nerve evoke a graded excitatory postsynaptic potential in the octopus cells. These EPSPs are ... excitatory and inhibitory input through the outermost molecular layer and the basal dendrites receiving excitatory and ... Excitatory acoustic input comes from auditory nerve fibers and also from stellate cells of the VCN. Acoustic input is also ... They are also called chopper cells, in reference to their ability to fire a regularly spaced train of action potentials for the ...
... is a form of postsynaptic potential inhibition that can be represented mathematically as reducing the excitatory potential by ... The amplitude of subsequent excitatory postsynaptic potential (EPSP) is reduced by this, in accordance with Ohm's Law. This ... at least on subthreshold postsynaptic potentials. In a 2005 article, researchers Abbott and Chance state that "Although the ... simple scenario arises if the inhibitory synaptic reversal potential is identical to the resting potential.[citation needed] ...
The excitatory postsynaptic potential (EPSP) produced by activation of an NMDA receptor also increases the concentration of ... Therefore, NMDA receptors will only open if glutamate is in the synapse and concurrently the postsynaptic membrane is already ...
... they can be classified as a type of field excitatory postsynaptic potentials. In some areas of the brain, such as the ... In neuroscience, a population spike (PS) is the shift in electrical potential as a consequence of the movement of ions involved ... Because these neurons are in the same orientation, the extracellular signals from the generation of action potentials don't ... The first interpretations of hippocampal field potentials were developed by Per Andersen.. ...
... in chromatolytic motor neurons is the significant reduction in size of the monosynaptic excitatory postsynaptic potentials ( ... This functional change to the anterior horn neurons could result in the elimination of certain excitatory synaptic inputs and ... then potential therapies could be developed for halting the chromatolytic response of neurons and ameliorating the detrimental ...
In comparison to Drosophila melanogaster, M. scalaris has decreased excitatory postsynaptic potentials (EPSPs) and facilitation ...
... theory BCM theory Electrical synapse Excitatory postsynaptic potential Homeostatic plasticity Inhibitory postsynaptic potential ... Depressed excitatory postsynaptic potentials (EPSPs) result from this particular stimulation pattern. The magnitude of calcium ... When postsynaptic action potential firing occurs prior to presynaptic afferent firing, both presynaptic endocannabinoid (CB1) ... Spike timing-dependent plasticity (STDP) refers to the timing of presynaptic and postsynaptic action potentials. STDP is a form ...
This Ca2+ influx is increased by excitatory postsynaptic potentials (EPSPs) produced by NMDA receptors, activating Ca2+-based ... resulting in a depolarization from the resting membrane potential of a neuron to lead to a graded potential or action potential ... Initiation or inhibition of action potential in postsynaptic cell depending on whether the neurotransmitters are excitatory or ... As with sodium ions, graded potentials and action potentials are also dependent on potassium channels. While influx of Na+ ions ...
... where activation leads to an excitatory postsynaptic potential (EPSP), mainly by increased Na+ and K+ permeability. ...
... to pre-synaptic action potentials and exhibit both excitatory postsynaptic potentials and inhibitory postsynaptic potentials. ... Its potential functions can be placed into four non-exclusive categories:[citation needed] discriminating among odors enhancing ... In this specific case, mitral cells release the excitatory neurotransmitter glutamate, and granule cells release the inhibitory ... Vomeronasal sensory neurons provide direct excitatory inputs to AOB principle neurons called mitral cells which are transmitted ...
The excitatory postsynaptic potential (EPSP) produced by activation of an NMDA receptor increases the concentration of Ca2+ in ... Removal of D-serine can block NMDA-mediated excitatory neurotransmission in many areas. Recently, it has been shown that D- ... Unlike many other NO donors, alkyl nitrates do not have potential NO associated neurotoxic effects. Alkyl nitrates donate NO in ... Berg LK, Larsson M, Morland C, Gundersen V (January 2013). "Pre- and postsynaptic localization of NMDA receptor subunits at ...
In CS pacemakers, NE increases only the amplitude of the depolarizing drive potential and the number of action potentials ... This is due to the reduction of excitatory synaptic transmission in a nucleus and increased excitability in motor neurons ... P/Q-type calcium channels are mainly responsible for the release of neurotransmitters that excite, or activate, postsynaptic ... which allows neurons to intrinsically fire action potentials at sub-threshold membrane potentials. Studies have shown that the ...
... post-synaptic cells compensate for the loss of adequate neurotransmitter by increasing the expression of post-synaptic ... Substance P is a key first responder to most noxious/extreme stimuli (stressors), i.e., those with a potential to compromise ... Substance P coexists with the excitatory neurotransmitter glutamate in primary afferents that respond to painful stimulation.[ ... Hesketh PJ (Jul 2001). "Potential role of the NK1 receptor antagonists in chemotherapy-induced nausea and vomiting". Supportive ...
S(-) form of barbiturate have shown more depressant activity while the R(+) isomers have an excitatory effect.[28] ... Perrais D, Ropert N (Jan 1999). "Effect of zolpidem on miniature IPSCs and occupancy of postsynaptic GABAA receptors in central ... "Beyond classical benzodiazepines: novel therapeutic potential of GABAA receptor subtypes". Nature Reviews. Drug Discovery. 10 ... Benzodiazepines enhance the receptor affinity for GABA by decreasing the decay of spontaneous miniature inhibitory postsynaptic ...
Glutamate is the brain's major excitatory neurotransmitter and its release can trigger the depolarization of postsynaptic ... action potential frequencies that were mediated by an increase in the amplitude of GABAergic inhibitory postsynaptic currents ( ... BDNF modulates excitatory and inhibitory synaptic transmission by inhibiting GABAA-receptor-mediated post-synaptic currents.[87 ... This suggests BDNF increases excitatory synaptic signaling partly through the post-synaptic suppression of GABAergic signaling ...
excitatory postsynaptic potential. • ion transmembrane transport. Sources:Amigo / QuickGO. Orthologs. Species. Human. Mouse. ... postsynaptic membrane. • cell projection. • membrane. • plasma membrane. • synapse. • integral component of plasma membrane. • ... integral component of postsynaptic specialization membrane. Biological process. • ion transport. • synaptic transmission, ...
"Gamma-Hydroxybutyrate inhibits excitatory postsynaptic potentials in rat hippocampal slices". European Journal of Pharmacology ... Potential treatment modalities into biochemical and neurological correction should aim to reduce one or both while not ... The GABA(B) receptor antagonist, SGS-742, is currently being tested as a potential therapeutic in an NIH phase II clinical ... This disruption has the potential to impair glutamate homeostasis and may lead to uncoupling of the normal balance between ...
Action potential. *Postsynaptic potential *Excitatory. *Inhibitory. Long term. *Axoplasmic transport. *Neuroregeneration/Nerve ... and ICP is calculated directly from the phase difference between the excitatory signal and response detected with a second ... changes in the circumference of the cranium are calculated from the phase difference between a sinusoidal excitatory signal, ...
Mossy fibers make an excitatory connection onto granule cells which cause the granule cell to fire an action potential. ... The nature of the calcium signals that control the presynaptic and postsynaptic function of the olfactory bulb granule cells ... This connection is excitatory as glutamate is released. The parallel fibers and ascending axon synapses from the same granule ... In the cerebellar cortex there are a variety of inhibitory neurons (interneurons). The only excitatory neurons present in the ...
... due to the influx of calcium into the post-synaptic cell, which are the most analyzed forms of plasticity at excitatory ... The distinctive structure of nerve cells allows action potentials to travel directionally (from dendrites to cell body down the ... The postsynaptic cell can be regulated by altering the function and number of its receptors. Changes in postsynaptic signaling ... postsynaptic) cell. Both the presynaptic and postsynaptic sites contain extensive arrays of a molecular machinery that link the ...
Chang RC, Stout S, Miller RR (January 2004). "Comparing excitatory backward and forward conditioning". The Quarterly Journal of ... Presynaptic activation of protein kinase A and postsynaptic activation of NMDA receptors and its signal transduction pathway ... they are a potential coincidence detector that could mediate spike timing dependent plasticity. STDP constrains LTP to ...
alpha-1 adrenergic receptor activation, by norepinephrine, decreases glutamatergic excitatory postsynaptic potentials at AMPA ... The field potentials measured for artificially stimulated CDC were eventually much stronger than that of a normal hearing cat.[ ... An evoked response study of congenitally deaf kittens used local field potentials to measure cortical plasticity in the ... "Preservation of Auditory P300-Like Potentials in Cortical Deafness". PLoS ONE. 7 (1): e29909. Bibcode:2012PLoSO...729909C. doi ...
Connections were checked, e.g., by means of intracellular recording postsynaptic potentials, horseradishperoxidase or cobalt- ... First, the retina is connected to the optic tectum by at least three types of ganglion cells, each with an excitatory receptive ... Arrows: excitatory connections; lines with terminal dots: inhibitory influences. ... excitatory input; lines with dots: inhibitory influences. After Ewert and Schwippert 2006 ...
NMDARs, on the other hand, do not open directly because their pores are occluded at resting membrane potential by Mg2+ ions. ... Calcineurin interacts with an endocytotic complex at the postsynaptic zone, explaining its effects on LTD.[62] The complex, ... and are thus responsible for most of the fast excitatory synaptic transmission in the central nervous system.[17] The AMPAR's ... Both AMPA and NMDA receptors, however, have an equilibrium potential near 0 mV. The prevention of calcium entry into the cell ...
Excitatory postsynaptic potential. *Excited (disambiguation). *Excited state, of an atom, molecule or nucleus ...
Excitatory postsynaptic potential, and Inhibitory postsynaptic potential. In general, action potentials that reach the synaptic ... The combined excitatory and inhibitory postsynaptic potentials of such inputs can begin a new action potential in the post- ... Action potentials are most commonly initiated by excitatory postsynaptic potentials from a presynaptic neuron.[18] Typically, ... The action potential in a normal skeletal muscle cell is similar to the action potential in neurons.[56] Action potentials ...
They can result from postsynaptic potentials from synchronous inputs or from intrinsic properties of neurons. ... Depending on the properties of the connection, such as the coupling strength, time delay and whether coupling is excitatory or ... Evoked potentials and event-related potentials are obtained from an electroencephalogram by stimulus-locked averaging, i.e. ... Neurons generate action potentials resulting from changes in the electric membrane potential. Neurons can generate multiple ...
integral component of postsynaptic membrane. • integral component of presynaptic membrane. Biological process. • detection of ... This is the main excitatory receptor subtype among the GPCRs for serotonin, although 5-HT2A may also have an inhibitory effect[ ... Abbas A, Roth BL (December 2008). "Pimavanserin tartrate: a 5-HT2A inverse agonist with potential for treating various ... Downregulation of post-synaptic 5-HT2A receptor is an adaptive process provoked by chronic administration of selective ...
Hargreaves RJ, Hill RG, Iversen LL (1994). Neuroprotective NMDA antagonists: the controversy over their potential for adverse ... NMDA is an excitatory receptor in the brain, when activated normally the receptor acts as an ion channel and there is an influx ... Findings demonstrate that presynaptic nAChRs and NMDA receptor interactions influence postsynaptic maturation of glutamatergic ... Johnson, K M; Jones, S M (April 1990). "Neuropharmacology of Phencyclidine: Basic Mechanisms and Therapeutic Potential". Annual ...
Those that release excitatory vesicles are referred to as excitatory postsynaptic potential (EPSP). Alternatively, inhibitory ... graded potentials and action potentials. Graded potentials occur when the membrane potential depolarizes and hyperpolarizes in ... which re-polarizes the membrane potential towards the resting membrane potential. Repolarization of the membrane potential ... An action potential on the other hand is an all-or-none electrical impulse. Despite being slower than graded potentials, action ...
Meister, M; Wong, R.O.L; Baylor, D.A; Shatz, C.J (1991). "Synchronous bursts of action potentials in ganglion cells of the ... This is followed by recruitment of postsynaptic proteins to the site of contact. Stephen Smith and colleagues have shown that ... act as the main excitatory neuronal stem cell of the cerebral cortex[21][22] or translocate to the cortical plate and ... Neuroligins are concentrated at the postsynaptic site and act via neurexins concentrated in the presynaptic axons. SynCAM is a ...
... causing an inhibitory postsynaptic potential (IPSP). Strychnine is a strong antagonist at ionotropic glycine receptors, whereas ... glutamatergic receptors which are excitatory.[30] The LD50 of glycine is 7930 mg/kg in rats (oral),[31] and it usually causes ...
Action potential. *Postsynaptic potential *Excitatory. *Inhibitory. Long term. *Axoplasmic transport. *Neuroregeneration/Nerve ... extracellular single-unit recording and recording of local field potentials, as well as some of the methods of calcium imaging ...
He predicted that the current generated by an excitatory postsynaptic potential (EPSPs) would result in a higher voltage change ... Burke later demonstrated that there was a graded decrease of both EPSP and inhibitory post synaptic potential (IPSP) amplitudes ... In medical electrodiagnostic testing for a patient with weakness, careful analysis of the "motor unit action potential" (MUAP) ... This is thought to be due to the interaction of excitatory and inhibitory motoneuronal inputs. ...
Con-G blocks NMDAR-mediated excitatory postsynaptic currents (EPSCs). Con-G reduces the strength of excitotoxic intracellular ... Con-G shows potential as a neuroprotective agent in ischemic and excitotoxic brain injury, neuronal apoptosis, pain, epilepsy, ...
The D2Lh form may function as a classical post-synaptic receptor, i.e., transmit information (in either an excitatory or an ... Schneier FR, Liebowitz MR, Abi-Dargham A, Zea-Ponce Y, Lin SH, Laruelle M (2000). "Low dopamine D(2) receptor binding potential ...
Their effect on target cells is usually excitatory. The M2 and M4 subtypes are Gi/Go-coupled; they decrease intracellular ... When a motor neuron generates an action potential, it travels rapidly along the nerve until it reaches the neuromuscular ... 4) Acetylcholine binds to postsynaptic receptors. (5) This binding causes ion channels to open and allows sodium ions to flow ... Thus, ACh is excitatory on skeletal muscle; the electrical response is fast and short-lived. ...
negative regulation of action potential. • regulation of feeding behavior. • negative regulation of ion transport. • response ... By reducing the concentration of glutamate released below the threshold necessary to depolarize the postsynaptic receptor NMDA, ... Consistent with the variable expression of both excitatory glutamate and inhibitory GABA interneurons in both the basal ... In terms of function, the inhibition of intracellular cAMP expression shortens the duration of pre-synaptic action potentials ...
... which elicit excitatory postsynaptic potentials (EPSP) in the dorsal horn of the spinal cord. That message is then relayed to ... Ebert, U; Koch, M (September 1997). "Acoustic startle-evoked potentials in the rat amygdala: effect of kindling". Physiology & ... The close association between astrocytes and presynaptic and postsynaptic terminals as well as their ability to integrate ... Under normal conditions, pain conduction begins with some noxious signal followed by an action potential carried by nociceptive ...
As a result, further GABA binding becomes inhibited and inhibitory postsynaptic potentials are no longer relevant. ... There have been numerous reports of excitatory GABAA receptors. According to the excitatory GABA theory, this phenomenon is due ... The increased chloride conductance drives the membrane potential towards the reversal potential of the Cl¯ ion which is about - ... However, the excitatory GABA theory has been questioned as potentially being an artefact of experimental conditions, with most ...
In neuroscience, an excitatory postsynaptic potential (EPSP) is a postsynaptic potential that makes the postsynaptic neuron ... generating an excitatory postsynaptic current. This depolarizing current causes an increase in membrane potential, the EPSP. ... The flow of ions that causes an EPSP is an excitatory postsynaptic current (EPSC). EPSPs, like IPSPs, are graded (i.e. they ... These are the opposite of inhibitory postsynaptic potentials (IPSPs), which usually result from the flow of negative ions into ...
Associations of Excitatory Postsynaptic Potentials with chemical compounds. *Gene context of Excitatory Postsynaptic Potentials ... Gene context of Excitatory Postsynaptic Potentials. *Frequency facilitation of field excitatory postsynaptic potentials, a form ... Chemical compound and disease context of Excitatory Postsynaptic Potentials. *Biological context of Excitatory Postsynaptic ... the fast nicotinic excitatory postsynaptic potential while having no effect on the slow excitatory postsynaptic potential or ...
... excitatory postsynaptic potentials include Postsynaptic Recordings at Afferent Dendrites Contacting Cochlear Inner Hair Cells ... Postsynaptic Recordings at Afferent Dendrites Contacting Cochlear Inner Hair Cells: Monitoring Multivesicular Release at a ...
Antibodies for proteins involved in positive regulation of excitatory postsynaptic potential pathways, according to their ... Antibodies for proteins involved in positive regulation of excitatory postsynaptic potential pathways; according to their ...
Calcium transients in dendrites of neocortical neurons evoked by single subthreshold excitatory postsynaptic potentials via low ... Calcium transients in dendrites of neocortical neurons evoked by single subthreshold excitatory postsynaptic potentials via low ... Calcium transients in dendrites of neocortical neurons evoked by single subthreshold excitatory postsynaptic potentials via low ... Calcium transients in dendrites of neocortical neurons evoked by single subthreshold excitatory postsynaptic potentials via low ...
What is Excitatory postsynaptic potentials? Meaning of Excitatory postsynaptic potentials medical term. What does Excitatory ... Looking for online definition of Excitatory postsynaptic potentials in the Medical Dictionary? Excitatory postsynaptic ... excitatory postsynaptic potential. (redirected from Excitatory postsynaptic potentials) ex·cit·a·to·ry post·syn·ap·tic po·ten· ... excitatory postsynaptic potential (EPSP). a reduction in the RESTING POTENTIAL of a postsynaptic cell caused by the arrival of ...
Excitatory post-synaptic potentials (EPSPs) depolarize the membrane and move the potential closer to the threshold for an ... This is the case for both excitatory and inhibitory postsynaptic potentials. Synaptic potentials are not static. The concept of ... decreasing the likelihood of an action potential occurring. The Excitatory Post Synaptic potential is most likely going to be ... Synaptic potential refers to the potential difference across the postsynaptic membrane that results from the action of ...
Simultaneous field excitatory postsynaptic potential (fEPSP) recordings from stratum radiatum and somatic whole-cell recordings ... Field excitatory postsynaptic potential (fEPSP) recordings. The extracellular electrophysiology was performed in both interface ... A potential scenario is as follows: first synapses acquire CP-AMPARs, next these are replaced by more CI-AMPARs. Thereafter LTP ... Two distinct postsynaptic forms of LTP at CA1 synapses. The division of NMDA receptor-dependent LTP into multiple components ...
An excitatory post-synaptic potential (EPSP) occurs when positive ions depolarise the post-synaptic membrane. EPSP is a graded ... Excitatory postsynaptic potential. From The School of Biomedical Sciences Wiki. Revision as of 22:57, 15 November 2018 by ... Retrieved from "" ... potential, it increases the likelihood of a postsynaptic action potential occurring[1].. ...
Dopamine enhances both electrotonic coupling and chemical excitatory postsynaptic potentials at mixed synapses. Proceedings of ... Dopamine enhances both electrotonic coupling and chemical excitatory postsynaptic potentials at mixed synapses. / Pereda, ... title = "Dopamine enhances both electrotonic coupling and chemical excitatory postsynaptic potentials at mixed synapses", ... T1 - Dopamine enhances both electrotonic coupling and chemical excitatory postsynaptic potentials at mixed synapses ...
Presynaptic suppression of excitatory postsynaptic potentials in rat ventral horn neurons by muscarinic agonists. / Jiang, Z. G ... Presynaptic suppression of excitatory postsynaptic potentials in rat ventral horn neurons by muscarinic agonists. Brain ... Jiang, Z. G. ; Dun, N. J. / Presynaptic suppression of excitatory postsynaptic potentials in rat ventral horn neurons by ... Presynaptic suppression of excitatory postsynaptic potentials in rat ventral horn neurons by muscarinic agonists. ...
... an excitatory postsynaptic potential is a temporary depolarization of postsynaptic membrane potential caused by the flow of ... positively charged ions into the postsynaptic cell as a result of opening of ligand-sensitive channels. They are th... Lees ...
The aim of this study is to further measure the effect of 632.8-nm helium-neon laser on fast excitatory postsynaptic potential ... Effect of helium-neon laser on fast excitatory postsynaptic potential of neurons in the isolated rat superior cervical ganglia[ ... Effect of helium-neon laser on fast excitatory postsynaptic potential of neurons in the isolated rat superior cervical ganglia ... and even cause action potential at the end of the first 1-2 minutes, the f-EPSP could descend and last for 3-8 minutes. But the ...
From some sources, Ive read that excitatory postsynaptic potentials (EPSPs) decay over time, which would imply that they ... How many action potentials from presynaptic neurons would be required to make a postsynaptic neuron fire? ... Do action potential thresholds vary in "capacity" significantly, and if so, does input frequency correspond to action potential ... Is the Resting Potential and Action Potential Thresholds the same across all neurons in a network? ...
The excitatory postsynaptic potential. *The excitation (magnetic) provided with an electrical generator or alternator ...
... excitatory postsynaptic potentials in guinea pig hippocampal slices: Binomial approach. ... Quantal parameters of "minimal" excitatory postsynaptic potentials in guinea pig hippocampal slices: Binomial approach. Voronin ... excitatory postsynaptic potentials in guinea pig hippocampal slices: Binomial approach. Experimental Brain Research, 89(2), 248 ...
Abbreviations: AP, action potential; EC, entorhinal cortex; EPSP, excitatory postsynaptic potential; LTD, long-term depression ... 0.1 Hz for measurement of excitatory postsynaptic potentials (EPSPs) before and after conditioning] delivered by a constant- ... The temporal order of repeated pairing of pre- and postsynaptic action potentials (APs) plays a key role in determining the ... Increasing Ca2+ transients by broadening postsynaptic action potentials enhances timing-dependent synaptic depression. Yu-Dong ...
excitatory postsynaptic potential IEA Inferred from Electronic Annotation. more info. ion transmembrane transport IBA Inferred ... Highly calcium permeable postsynaptic nicotinic acetylcholine receptors, organism-specific biosystemPostsynaptic acetylcholine ... Postsynaptic nicotinic acetylcholine receptors, organism-specific biosystem (from REACTOME) Postsynaptic nicotinic ... regulation of membrane potential IBA Inferred from Biological aspect of Ancestor. more info ...
excitatory postsynaptic potential ISS Inferred from Sequence or Structural Similarity. more info ...
excitatory postsynaptic potential V i v X d ʁAEPSP exon-skipping G L \ X L b s O ...
Excitatory Postsynaptic Potential. GALT. Gut associated lymphoid tissue. GEP. Gastroenteropancreatic. GLP-2. Glucagon-like ... Hennig GW, Brookes SJH, Costa M (1997) Excitatory and inhibitory motor reflexes in the isolated guinea-pig stomach. J Physiol ... Daniel EE, Sarna SK (1976) Distribution of excitatory vagal fibers in canine gastric wall to control motility. Gastroenterology ... Tan LL, Bornstein JC, Anderson CR (2008) Distinct chemical classes of medium-sized transient receptor potential channel ...
Excitatory postsynaptic potentials evoked by ventral root stimulation in neonate rat motoneurons in vitro. / Jiang, Z. G.; Shen ... Excitatory postsynaptic potentials evoked by ventral root stimulation in neonate rat motoneurons in vitro. Journal of ... Jiang, Z. G. ; Shen, E. ; Wang, M. Y. ; Dun, N. J. / Excitatory postsynaptic potentials evoked by ventral root stimulation in ... Jiang, Z. G., Shen, E., Wang, M. Y., & Dun, N. J. (1991). Excitatory postsynaptic potentials evoked by ventral root stimulation ...
Rodgers, R. B. ; Staser, J. S. ; Si, K. ; Friedman, R. N. / The effect of tryptamine on excitatory postsynaptic potentials at a ... Rodgers, R. B., Staser, J. S., Si, K., & Friedman, R. N. (1999). The effect of tryptamine on excitatory postsynaptic potentials ... Fingerprint Dive into the research topics of The effect of tryptamine on excitatory postsynaptic potentials at a crayfish ... Rodgers, RB, Staser, JS, Si, K & Friedman, RN 1999, The effect of tryptamine on excitatory postsynaptic potentials at a ...
Excitatory Postsynaptic Potentials * In Vitro Techniques * Kinetics * Neurotransmitter Agents / metabolism* * Patch-Clamp ... i to peak values as low as 25 microM can account for transmitter release during single presynaptic action potentials. The ...
Levy, R. B., Reyes, A. D., & Aoki, C. (2006). Nicotinic and muscarinic reduction of unitary excitatory postsynaptic potentials ... Levy, RB, Reyes, AD & Aoki, C 2006, Nicotinic and muscarinic reduction of unitary excitatory postsynaptic potentials in ... T1 - Nicotinic and muscarinic reduction of unitary excitatory postsynaptic potentials in sensory cortex; dual intracellular ... title = "Nicotinic and muscarinic reduction of unitary excitatory postsynaptic potentials in sensory cortex; dual intracellular ...
Contemporary models assume that multiple synapses must act cooperatively to induce the postsynaptic activity required for ... and postsynaptic activity was proposed by Hebb as a cellular mechanism for learning. ... Excitatory Postsynaptic Potentials / physiology * Long-Term Potentiation* * Pyramidal Cells / cytology* * Pyramidal Cells / ... Rather, locally generated and spatially restricted regenerative potentials (dendritic spikes) contribute to the postsynaptic ...
... opening of ion channels permeable to the following ions can lead to excitatory postsynaptic potentials (EPSPs). ... At chemical synapses, opening of ion channels permeable to the following ions can lead to excitatory postsynaptic potentials ( ...
... mediated excitatory postsynaptic potential is increased in amplitude, although the NMDA(R)-mediated excitatory postsynaptic ... mediated excitatory postsynaptic potential is increased in amplitude, although the NMDA(R)-mediated excitatory postsynaptic ... mediated excitatory postsynaptic potential is increased in amplitude, although the NMDA(R)-mediated excitatory postsynaptic ... mediated excitatory postsynaptic potential is increased in amplitude, although the NMDA(R)-mediated excitatory postsynaptic ...
  • In neuroscience, an excitatory postsynaptic potential (EPSP) is a postsynaptic potential that makes the postsynaptic neuron more likely to fire an action potential. (
  • The flow of ions that causes an EPSP is an excitatory postsynaptic current (EPSC). (
  • This depolarizing current causes an increase in membrane potential, the EPSP. (
  • The Schaffer collaterals make excitatory synapses onto these dendrites, and so when they are activated, there is a current sink in stratum radiatum: the field EPSP. (
  • An excitatory post-synaptic potential (EPSP) occurs when positive ions depolarise the post-synaptic membrane. (
  • EPSP is a graded potential , it increases the likelihood of a postsynaptic action potential occurring [1] . (
  • The aim of this study is to further measure the effect of 632.8-nm helium-neon laser on fast excitatory postsynaptic potential (f-EPSP) of postganglionic neurons in isolated rat superior cervical ganglia by means of intracellular recording techniques. (
  • 0.05, paired t test) and even cause action potential at the end of the first 1-2 minutes, the f-EPSP could descend and last for 3-8 minutes. (
  • This means a single EPSP/IPSP is typically not enough to trigger an action potential. (
  • Does the refractory period of an action potential affect its originating EPSP? (
  • While model neurons like the leaky integrate and fire may use a simplification in which the neuron forgets all previous information when it emits a spike, in a biological neuron, the synapse and the soma are relatively electrically isolated from each other, so the voltage activity of the action potential does not make the synapse "forget" the EPSP. (
  • Ovariectomized animals, chronically implanted with a recording electrode in the cell body layer of CA1 and a stimulating electrode in stratum radiatum, were used to record evoked field potentials (population spike (PS) and summed EPSP) daily for at least 4 days before injection of sesame oil or 100 microg of estradiol benzoate per kg b.w. (
  • Moreover, tonic inhibition elevated the action potentials (AP) threshold and improved the temporal precision of output functions in a SBC model with phase-dependent input conductance.We conclude that activity-dependent, summating inhibition contributes to high temporal precision of SBC spiking by filtering out weak and poorly timed EPSP.Moreover, inhibitory parameters determined in slice recordings provide a good estimate of inhibitory mechanisms apparently active in vivo. (
  • This extracellular signal recorded from a population of neurons is the field potential. (
  • The results suggest that muscarinic agonists inhibit synaptic transmission of ventral horn neurons including motoneurons by a presynaptic mechanism in reducing the output of excitatory transmitters. (
  • Jiang, ZG & Dun, NJ 1986, ' Presynaptic suppression of excitatory postsynaptic potentials in rat ventral horn neurons by muscarinic agonists ', Brain research , vol. 381, no. 1, pp. 182-186. (
  • Some of these mechanisms rely on changes in both the presynaptic and postsynaptic neurons, resulting in a prolonged modification of the synaptic potential. (
  • How many action potentials from presynaptic neurons would be required to make a postsynaptic neuron fire? (
  • Is the Resting Potential and Action Potential Thresholds the same across all neurons in a network? (
  • Graph that records electrical activity through the skull or from the brain and represents graded potentials of many neurons. (
  • The Melzack and Wall circuit was slightly modified by using strictly excitatory nociceptive afferents (in the original arrangement, nociceptive afferents were considered excitatory when they project to central transmission neurons and inhibitory when projecting to substantia gelatinosa). (
  • One controversial detail of the model (see Figure 4 in [ 1 ]) is that afferent nociceptors produce an excitatory stimulus on first central transmission (CT) neurons and, simultaneously, an inhibitory stimulus on neurons in the SG. (
  • This fact seems to contradict the idea that axon terminals of excitatory neurons are all excitatory, and axon terminals of inhibitory neurons are all inhibitory. (
  • During quiescence, TC neurons showed phasic inhibitory postsynaptic potentials (IPSPs) that coincided with paroxysmal depolarizing shifts in the simultaneously recorded cortical neuron. (
  • With this model, RE neurons receiving repeated strong excitatory input produced TC neuron quiescence due to burst-duration-associated augmentation of GABA B current. (
  • After seizure cessation, TC neurons returned to resting membrane potential. (
  • We have found changes in postsynaptic AMPA receptor sensitivity in neurons of the chick cochlear nucleus, the nucleus magnocellularis (nMAG), by photolysis of caged glutamate immediately after activation of a single synaptic input. (
  • These findings confirm that postsynaptic neurons may use desensitization to regulate the strength of transmission on a synapse-specific basis. (
  • Neurons of the avian nucleus magnocellularis transmit phase-locked action potentials of the auditory nerve in a pathway that contributes to sound localization based on interaural timing differences. (
  • This time series, termed multi-unit activ- ity (MUA), is the summation of the action potentials of multiple neurons that are in close proximity to the recording electrode. (
  • Inhibition of the methylation of cytosines in the DNA of cultured cortical neurons enhanced their intrinsic membrane excitability so that the neurons generated more action potentials in response to a stimulus. (
  • Action potentials occur in several types of animal cells , called excitable cells , which include neurons , muscle cells , endocrine cells, and in some plant cells . (
  • Bath-application of either TG003 (1 μM) or IC261 (1 μM) had only marginal effects on spontaneous excitatory postsynaptic currents (sEPSCs) recorded in the substantia gelatinosa neurons of control mice. (
  • When multiple EPSPs occur on a single patch of postsynaptic membrane, their combined effect is the sum of the individual EPSPs. (
  • Larger EPSPs result in greater membrane depolarization and thus increase the likelihood that the postsynaptic cell reaches the threshold for firing an action potential. (
  • The neurotransmitter most often associated with EPSPs is the amino acid glutamate, and is the main excitatory neurotransmitter in the central nervous system of vertebrates. (
  • In addition to depolarizing the ventral horn cells including antidromically identified motoneurons in thin transverse neonatal rat spinal cord slice preparations, exogenously applied acetylcholine (ACh) suppressed the amplitude of excitatory postsynaptic potentials (EPSPs) either occurring spontaneously or elicited by stimulation of dorsal rootlets. (
  • Excitatory post-synaptic potentials (EPSPs) depolarize the membrane and move the potential closer to the threshold for an action potential to be generated. (
  • In order to depolarize a neuron enough to cause an action potential, there must be enough EPSPs to both depolarize the postsynaptic membrane from its resting membrane potential to its threshold and counterbalance the concurrent IPSPs that hyperpolarize the membrane. (
  • EPSPs on the postsynaptic neuron result from the main excitatory neurotransmitter, glutamate, binding to its corresponding receptors on the postsynaptic membrane. (
  • From some sources, I've read that excitatory postsynaptic potentials (EPSPs) decay over time, which would imply that they aren't abolished by action potentials. (
  • Plus, the classical leaky-integrate-and-fire neuron model implies that EPSPs are abolished by action potentials (although this could well be a simplification). (
  • begingroup$ @AliceD My reasoning is that 'basic' neuroscience falls within a cognitive science, much like neural network questions do (i.e., anyone would learn about action potentials and EPSPs during their undergrad and could answer it with a bit of reading, unlike more involved bio/neuro questions). (
  • The depolarizing responses were excitatory postsynaptic potentials (EPSPs), because they could be graded by varying the stimulus intensity and were reversibly abolished in low Ca 2+ solution. (
  • Membrane hyperpolarization increased the amplitude of EPSPs, and the mean extrapolated reversal potential was -4 mV. (
  • Brief bath application of 5-10 μM carbachol, a nonspecific cholinergic agonist, decreased the amplitude of evoked unitary excitatory postsynaptic potentials (EPSPs). (
  • At chemical synapses, opening of ion channels permeable to the following ions can lead to excitatory postsynaptic potentials (EPSPs). (
  • When an active presynaptic cell releases neurotransmitters into the synapse, some of them bind to receptors on the postsynaptic cell. (
  • citation needed] Quantal analysis refers to the methods used to deduce, for a particular synapse, how many quanta of transmitter are released and what the average effect of each quantum is on the target cell, measured in terms of amount of ions flowing (charge) or change in the membrane potential. (
  • Synaptic potential refers to the potential difference across the postsynaptic membrane that results from the action of neurotransmitters at a neuronal synapse. (
  • Synaptic potentials, unlike action potentials, degrade quickly as they move away from the synapse. (
  • Repeated induction of pre- and postsynaptic action potentials (APs) at a fixed time difference leads to long-term potentiation (LTP) or long-term depression (LTD) of the synapse, depending on the temporal order of pre- and postsynaptic activity. (
  • An excitatory synapse on the soma is more effective in evoking action potentials in the postsynaptic neuron than an excitatory synapse on the tip of a dendrite. (
  • Thus, despite correlative data, there is no direct evidence that glutamate released from a synapse reduces the sensitivity of the postsynaptic receptors. (
  • When an action potential travels to the synapse, the rapid depolarization causes calcium ion channels to open. (
  • Since presynaptic inhibition reduces the number of Ca channels opened by an action potential, our data suggest cooperativity between Ca channel microdomains to initiate vesicle fusion at this synapse. (
  • 10 μM) or strychnine (1 μM), suggesting that this response represents an inhibitory postsynaptic potential (IPSP) mediated by glycine or a related substance released from inhibitory interneurons subsequent to their activation by axon collaterals in a manner analogous to the Renshaw cell circuitry described for the cat motoneurons. (
  • Psychostimulants block the IPSP mediated by glutamate, while leaving the excitatory postsynaptic potential in place. (
  • In recent years, there has been an abundance of research on how to prolong the effects of a synaptic potential, and more importantly, how to enhance or reduce its amplitude. (
  • In fascia dentata the non-NMDA(R)-mediated excitatory postsynaptic potential is increased in amplitude, although the NMDA(R)-mediated excitatory postsynaptic potential is reduced for a given presynaptic input. (
  • For example, trains of high-frequency stimulation to the hippocampus induce an activity-dependent increase in the amplitude of excitatory postsynaptic potentials, lasting for at least a period of hours. (
  • We propose a model where presynaptic inhibition causes localized shunting of an actively propagated action potential in the vicinity of release sites, which can recover its amplitude outside the shunted region. (
  • However, there is an inherent time delay to the initiation of contraction due to the need to stimulate enough action potentials to increase EJP amplitude sufficiently ( Atwood, 1976 ). (
  • This local depolarization is known as an excitatory synaptic potential , and its amplitude is determined by the number of vesicles released from the presynaptic cell. (
  • Methods: Field excitatory postsynaptic potentials (fEPSPs), spontaneous excitatory postsynaptic currents (sEPSCs) and miniature spontaneous excitatory postsynaptic currents (mEPSCs) were recorded, by using in vitro field potential electrophysiology and whole-cell patch clamp techniques in acute hippocampal slices from rats. (
  • This hypothesis was tested by applying dopamine locally in the vicinity of the lateral dendrite of the goldfish Mauthner cell (M cell) and monitoring the composite electrotonic and chemical excitatory postsynaptic potentials and currents evoked by ipsilateral eighth nerve stimulation. (
  • Likewise, when the postsynaptic cell was depolarized under voltage clamp to allow NMDA receptor activation in the presence of 1 mM Mg +2 , synaptic currents were reduced by nicotine. (
  • Using the patch-clamp technique, the frequencies and amplitudes of excitatory spontaneous postsynaptic currents (EPSCs) were determined, theirdistributions were analyzed and the basicquantal parameters were calculated. (
  • Slices were bathed in antagonists of NMDA, GABA A , and glycine receptors (100 μ m d,l 2-amino-5-phosphonovalerate, 5 μ m SR-95531, and 2 μ m strychnine, respectively) to isolate AMPA receptor-mediated eEPSCs and miniature excitatory postsynaptic currents (mEPSCs). (
  • 5-HT-induced broadening of the sensory neuron action potential in the presence of tetraethylammonium/nifedipine, which is mediated by modulation of the S-K + currents, was used an assay for the AC-cAMP cascade. (
  • This temporary depolarization of postsynaptic membrane potential, caused by the flow of positively charged ions into the postsynaptic cell, is a result of opening ligand-gated ion channels. (
  • The reduction takes the membrane potential close to the THRESHOLD and, therefore, nearer to itself forming an ACTION POTENTIAL . (
  • As an example, consider a neuron with a resting membrane potential of -70 mV (millivolts) and a threshold of -50 mV. (
  • Is the Subject Area "Membrane potential" applicable to this article? (
  • Because the receptor channels remain open only as long as neurotransmitter is bound, and because binding is only transient, the synaptic potential is also brief and the membrane potential returns rapidly to its resting level. (
  • [b] These channels are shut when the membrane potential is near the (negative) resting potential of the cell, but they rapidly begin to open if the membrane potential increases to a precisely defined threshold voltage, depolarising the transmembrane potential. (
  • [b] When the channels open, they allow an inward flow of sodium ions, which changes the electrochemical gradient, which in turn produces a further rise in the membrane potential. (
  • The process proceeds explosively until all of the available ion channels are open, resulting in a large upswing in the membrane potential. (
  • The membrane potential remains near a baseline level until at some point in time, it abruptly spikes upward and then rapidly falls. (
  • Nearly all cell membranes in animals, plants and fungi maintain a voltage difference between the exterior and interior of the cell, called the membrane potential . (
  • As an action potential travels through the presynaptic neuron, the membrane depolarization causes voltage-gated calcium channels to open. (
  • Brief depolarization of a neuron membrane in response to stimulation, making the neuron more likely to produce an action potential. (
  • Unlike vertebrate skeletal neuromuscular junctions, EJPs produced in response to single presynaptic action potentials are small (50μ V to 2 mV), so temporal summation by itself cannot readily generate sufficient depolarization to cause contraction. (
  • Na + channels open at the beginning of the action potential, and Na + moves into the axon, causing depolarization . (
  • At excitatory synapses, the ion channel typically allows sodium into the cell, generating an excitatory postsynaptic current. (
  • Its ubiquity at excitatory synapses has led to it being called the excitatory neurotransmitter. (
  • Since in other systems single afferents establish mixed electrotonic and chemical excitatory synapses with their targets, dopamine might be expected there to depress one component of excitation while enhancing the other. (
  • Spatial summation refers to several excitatory stimuli from different synapses converging on the same postsynaptic neuron at the same time to reach the threshold needed to reach an action potential. (
  • The strength of changes in synaptic potentials across multiple synapses must be properly regulated. (
  • Synaptic physiology was investigated via patch-clamp recordings from bushy cells in brainstem slices during stimulation of auditory nerve fibers at 35°C. Compared with embryonic synapses (embryonic day 18), post-hatch chicks (post-hatch days 1-11) exhibited high probability of firing a well timed postsynaptic action potential during high-frequency stimulation of the auditory nerve. (
  • Animal models of SE have been employed to demonstrate that ongoing epileptic activity in the brain can affect both excitatory and inhibitory synapses and thus neuronal plasticity [ 12 - 15 ]. (
  • At electrical synapses , which are relatively rare in vertebrates, the membranes of the two cells are in tight contact, producing electrical coupling, which enables a nerve impulse (or action potential ) arriving at the presynaptic nerve ending to pass swiftly and reliably to the next cell. (
  • Chemical synapses are more complex, because the presynaptic and postsynaptic cells are physically separated by a minute gap (the synaptic cleft ), which prevents simple electrical transmission of the action potential to the postsynaptic cell. (
  • Acetylcholine is the excitatory transmitter at nerve-muscle synapses, and glutamate is the main excitatory transmitter in the central nervous system . (
  • Therefore, in the present study we tested whether TDE can modulate dendritic field excitatory postsynaptic potentials (fEPSPs), which indicate the neuronal synaptic function, in Cornu Ammonis 1 (CA1) hippocampal slices of normal rats as found in current AChE-I drugs used for AD therapy. (
  • Halogenated aromatic hydrocarbons suppress CA1 field excitatory postsynaptic potentials in rat hippocampal slices. (
  • Quantal parameters of "minimal" excitatory postsynaptic potentials in guinea pig hippocampal slices: Binomial approach. (
  • As a first step, we examined the effects of sevoflurane on excitatory synaptic transmission mediated by glutamate receptors in the CA1 area of rat hippocampal slices. (
  • Is the energy of an action potential divided among multiple axon terminals? (
  • Materials and Methods: The excitatory axon in the meropodite of the first and second walking limbs and the dactyl opener muscle of the crayfish were exposed. (
  • A 30 Hz stimulus was applied to the excitatory axon for 10 sec prior to data collection, and EJPs were recorded intracellularly for 10 sec from a superficial opener muscle fiber via a 3.0 M KCl glass micro-electrode. (
  • Propagation of an action potential on the membrane of an axon. (
  • Refers to the state of an axon in the repolarizing period during which a new action potential cannot be elicited (with some exceptions), because gate 2 of sodium channels, which is not voltage sensitive, is closed. (
  • b) Current proposal: all nociceptive and mechanoreceptor axon terminals are excitatory. (
  • This neuron's specialization is due to the absence of any mechanism in axons for guiding excitatory neurotransmitters from their origin at the neuron's soma to some specific axon terminals, while diverting inhibitory neurotransmitters to other terminals. (
  • The crayfish claw opener (abductor) muscle is innervated by a glutamate-releasing, excitatory axon and a GABA (γ-aminobutyric acid)-releasing, inhibitory axon ( Van Harreveld, 1939 ) ( Fig. 1 ). (
  • As an action potential (nerve impulse) travels down an axon there is a change in polarity across the membrane of the axon. (
  • A key prediction of the peak-detector model is that broader dendritic APs should enhance timing-dependent LTP by increasing the Ca 2+ flux through NMDA receptors and postsynaptic voltage-gated Ca 2+ channels. (
  • In the present experiment, presynaptic fiber potentials and non-N-methyl-D-aspartate (NMDA(R)) and NMDA(R)-mediated synaptic responses in CA1 were compared in three ages of behaviorally characterized male F-344 rats. (
  • In the CA1 region, old rats showed approximately equivalent reductions in non-NMDA(R) and NMDA(R)-excitatory postsynaptic potential amplitudes for a given size of presynaptic fiber potential. (
  • LPS offspring mice displayed persistent microglial activation and increased CA3-CA1 excitatory synaptic strength, which can be explained in part by an increase in the probability of glutamate release, and reduced long-term synaptic potentiation compared to control mice. (
  • In the neuromuscular junction of vertebrates, EPP (end-plate potentials) are mediated by the neurotransmitter acetylcholine, which (along with glutamate) is one of the primary transmitters in the central nervous system of invertebrates. (
  • The Excitatory Post Synaptic potential is most likely going to be carried out by the neurotransmitters glutamate and acetylcholine, while the Inhibitory post synaptic potential will most likely be carried out by the neurotransmitters gamma-aminobutyric acid (GABA) and glycine. (
  • These are the opposite of inhibitory postsynaptic potentials (IPSPs), which usually result from the flow of negative ions into the cell or positive ions out of the cell. (
  • Inhibitory postsynaptic potentials (IPSPs) hyperpolarize the membrane and move the potential farther away from the threshold, decreasing the likelihood of an action potential occurring. (
  • These hyperpolarizations were associated with repetitive inhibitory postsynaptic potentials (IPSPs) coincident with paroxysmal depolarizations and spike bursts in cortical cells, and with long (200-300 ms) spike bursts in thalamic reticular (RE) cells ( Steriade and Contreras 1995 ). (
  • Although glutamate is best known as an excitatory transmitter, it also causes slow inhibitory postsynaptic potentials (IPSPs) in dopamine cells through activation of a metabotropic glutamate receptor. (
  • These observations are important for selecting preparations for and interpreting results of future studies using invertebrate models to examine excitatory neurotransmission mechanisms. (
  • Nociceptin/orphanin FQ selectively suppresses excitatory glutamatergic neurotransmission, while nocistatin selectively interferes with glycinergic and gamma-aminobutyric acid (GABA)-ergic transmission. (
  • The partial ORL1 receptor antagonist [phe1psi(CH(2)-NH)Gly(2)]nociceptin-(1-13)NH(2) competitively reversed the effects of nociceptin/orphanin FQ on excitatory neurotransmission (estimated pA(2) 6.43), but left the suppression of inhibitory synaptic transmission by nocistatin unaffected. (
  • For the field excitatory postsynaptic potentials (fEPSPs) recording, three-month old male Sprague-Dawley rats (200-250 g) were obtained from the Sun Yat-sen University, China. (
  • Simultaneous field excitatory postsynaptic potential (fEPSP) recordings from stratum radiatum and somatic whole-cell recordings were obtained in response to baseline stimulation of two independent SCCP inputs (Fig. 1a ). (
  • In particular, we focused on the influence of amnestic concentrations of sevoflurane, which produced amnestic actions but no hypnotic actions, on population spikes (PSs) and field excitatory postsynaptic potentials (fEPSPs). (
  • Subthreshold excitatory postsynaptic potentials (EP-SPs), mediated by the activation of glutamate receptor channels, caused a brief increase in dendritic [Ca2+]i. (
  • The type of potential produced depends on both the postsynaptic receptor, more specifically the changes in conductance of ion channels in the post synaptic membrane, and the nature of the released neurotransmitter. (
  • The released neurotransmitter then binds to its receptor on the postsynaptic neuron causing an excitatory or inhibitory response. (
  • In general, Gi-coupled mGlu receptor subtypes appear to negatively modulate excitatory (and possibly also inhibitory) neurotransmitter output when activated. (
  • α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor antagonists are of potential interest for the treatment of certain acute and chronic neurodegenerative diseases, including amyotrophic lateral sclerosis. (
  • Taken together, it has been suggested that 5-HT 2A receptor-mediated glutamate release is the final common pathway for the acute actions of psychedelics, and a potential underlying mechanism of therapeutic effects [ 16 ]. (
  • Loss of function in dVAP disrupts microtubule cytoskeleton and causes an increase in miniature excitatory post-synaptic potentials that correlates with an increase in post-synaptic glutamate receptor clustering. (
  • Although halothane and isoflurane seemed to depress glutamate receptor-mediated excitatory synaptic transmission in a dose-dependent manner, 13-15 details of sevoflurane actions on excitatory synaptic transmission remain lacking. (
  • The neurotransmitter molecules that are liberated diffuse across the cleft and interact with specialized protein receptor molecules in the postsynaptic cell membrane . (
  • summation of these potentials can lead to discharge of an impulse by the neuron. (
  • The two ways that synaptic potentials can add up to potentially form an action potential are spatial summation and temporal summation. (
  • Temporal summation refers to successive excitatory stimuli on the same location of the postsynaptic neuron. (
  • Summation has been referred to as a "neurotransmitter induced tug-of-war" between excitatory and inhibitory stimuli. (
  • In particular, certain members of the group II and group III mGlu receptors have been implicated in presynaptic negative modulation of excitatory glutamate and/or inhibitory GABA neuronal transmission, and that subject and its therapeutic implications are the focus of this article. (
  • Prolonged DNMT inhibition blunted the medium component of the after-hyperpolarization potential, an effect that would increase neuronal excitability, and was associated with reduced expression of the genes encoding small-conductance Ca 2+ -activated K + (SK) channels. (
  • However, classifying neurotransmitters as such is technically incorrect, as there are several other synaptic factors that help determine a neurotransmitter's excitatory or inhibitory effects. (
  • The quantity of neurotransmitters released can play a large role in the future strength of that synapse's potential. (
  • A type of postsynaptic potential where the binding of neurotransmitters with the postsynaptic receptors causes the opening of ion channels which results in hyperpolarization (or the net gain of negative charge across the membrane ) thus the firing of an action potential from the postsynaptic cell is less likely. (
  • In the case of neurotransmitters that excite the postsynaptic membrane, the pore permits positively-charged sodium ions to move into the cell, making the potential across its membrane less negative. (
  • As an indication of inhibition we used a paired-pulse stimulus protocol and calculated a ratio of the amplitudes of the second versus the first excitatory postsynaptic potential. (
  • Improvements in reliability and timing of postsynaptic spikes were accompanied by a developmental increase in steady-state EPSCs during stimulus trains and a decline in the extent of synaptic depression. (
  • These show that transient (around 0.5 ms) local elevations of [Ca2+]i to peak values as low as 25 microM can account for transmitter release during single presynaptic action potentials. (
  • It will need to be raised 20 mV in order to pass the threshold and fire an action potential. (
  • Synaptic potentials are small and many are needed to add up to reach the threshold. (
  • Since mechanoreceptors are low-threshold and their axons are myelinated, they produce high-rate action potentials. (
  • In general, the resting potential of a neuron is about -70mV and the firing threshold of an action potential is about -50mV. (
  • When there is a net gain of negative charge across the membrane of a postsynaptic neuron , the potential moves further to zero or away from the firing threshold. (
  • Inhibition reduced postsynaptic excitatory junction potentials (EJPs) below the threshold to initiate contraction. (
  • Memory-related plasticity also includes alterations in intrinsic membrane excitability mediated by changes in the abundance or activity of ion channels in the plasma membrane, which sets the threshold for action potential generation. (
  • Moreover, tonic inhibition elevated the action potentials (AP) threshold and improved the temporal precision of output functions in a SBC model with phase-dependent input conductance. (
  • 7 The results suggest that the decrease of the voltage-gated K + channel density from the soma along the apical dendrite of L5 pyramidal neurones helps to define a distal, low threshold region for the initiation of dendritic regenerative potentials. (
  • In response to a signal from another neuron , sodium- (Na + ) and potassium- (K + ) gated ion channels open and close as the membrane reaches its threshold potential . (
  • Both psychostimulants and opioids cause a presynaptic inhibition of GABA inhibitory postsynaptic potentials in dopamine cells, thus increasing their excitability and causing the release of dopamine. (
  • Action potential-mediated calcium (Ca) entry into excitor nerve terminal boutons during presynaptic inhibition and the effects of co-activation of the inhibitor on the kinetics of muscle contraction were studied at crayfish claw opener muscle. (
  • Dudel ( 1963 ) proposed a mechanism of presynaptic inhibition due to blocking of action potentials before they reached the terminals. (
  • While the postsynaptic neuron is at rest, Na+ / K+ pump proteins actively concentrated Na+ ions outside the cell and K+ ions inside the cell. (
  • They often act on receptors that act as channels for chloride ions, and generally make the interior of the postsynaptic cell even more negative ( hyperpolarization ). (
  • 15 16 17 In agreement with this, Hossmann et al 18 found an increase of somatosensory evoked potential amplitudes in rat brain in the first 24 hours after middle cerebral artery occlusion. (
  • Is pacemaker action potential considered a calcium dependent or sodium/calcium dependent? (
  • This phenomenon of spike-timing-dependent plasticity (STDP) is believed to arise by nonlinear processes that lead to larger calcium transients (and thus LTP) when presynaptic APs precede postsynaptic APs and smaller calcium transients (and thus LTD) when postsynaptic APs precede presynaptic APs. (
  • We confirmed that EC cells exhibit STDP and found that constitutively or artificially broadened postsynaptic APs lead to an increase in the dendritic calcium transient but shift the balance of STDP toward LTD, in contrast to what one would predict from the peak-detector model. (
  • When an action potential arrives in the terminal it stimulates the opening of calcium channels in the terminal membrane. (
  • Sodium-based action potentials usually last for under one millisecond, but calcium-based action potentials may last for 100 milliseconds or longer. (
  • We have recently discovered a phenomenon that may be related to intestinal hypersensitivity and hyper-reflexia, sustained slow postsynaptic excitation (SSPE), which occurs in intrinsic sensory neurones of the small intestine. (
  • The neuron will account for all the many incoming excitatory and inhibitory signals via summative neural integration, and if the result is an increase of 20 mV or more, an action potential will occur. (
  • Does an action potential abolish an excitatory postsynaptic potential? (
  • Can dendrite spines fire action potential toward the soma? (
  • In more global estimations, most of the energy consumption has been attributed to action potential generation ("spiking") and excitatory synaptic transmission ( Attwell and Laughlin, 2001 ). (
  • This plasticity is expressed when presynaptic activation is associated with a characteristically broad, postsynaptic action potential, lasting 7-15 ms, occurring within a window of up to 60-80 ms following synaptic activation. (
  • Hence, the postsynaptic potential is inhibitory since the probability to fire an action potential is reduced. (
  • We measured the effect of Ca 2+ chelation with fast 1,2-bis(2-aminophenoxy) ethane-tetraacetic acid (BAPTA) and slow ethyleneglycol-tetraacetic acid (EGTA) buffers on exocytosis, synaptic depression, and recovery of the readily releasable vesicle pool (RRP), after both single action potential (AP) and repetitive APs. (
  • 2000). The extracellu- lar spike reflects the intracellular action potential but its shape is dependent on multiple properties of the neuron (such as chan- nel concentration, dendritic tree structure) and the location of the electrode relative to the neuron (Henze et al. (
  • action potential or spike generated. (
  • If it is sufficiently large, the synaptic potential initiates an action potential in the cell. (
  • If the target cell is a neuron, the action potential sweeps along its fibre. (
  • Inhibitory transmitters also exist which render the post-synaptic cell less excitable and thus less likely to generate an action potential. (
  • The latter have sufficient potency to block action potential firing in vivo and in slice recordings. (
  • In muscle cells, for example, an action potential is the first step in the chain of events leading to contraction. (
  • After an action potential has occurred, there is a transient negative shift, called the afterhyperpolarization . (
  • In the Hodgkin-Huxley membrane capacitance model , the speed of transmission of an action potential was undefined and it was assumed that adjacent areas became depolarised due to released ion interference with neighbouring channels. (
  • Shape of a typical action potential. (
  • Electrical stimulation of ventral rootlets evoked, with or without an antidromic spike or initial segment potential, a depolarizing response (latency, 1-4.2 ms), a hyperpolarizing response (latency, 1.5-3.5 ms), or a combination of two preceding responses in 38, 6, and 8% of motoneurons investigated. (
  • Spherical bushy cells (SBCs) of the anteroventral cochlear nucleus (AVCN) receive input from large excitatory auditory nerve (AN) terminals, the endbulbs of Held, and mixed glycinergic/GABAergic inhibitory inputs. (
  • Broad action potentials can be evoked in vivo by either corollary discharge input or electrosensory input, and in vitro by parallel fiber stimulation. (
  • Bernard Katz pioneered the study of these mEPSPs at the neuromuscular junction (often called miniature end-plate potentials) in 1951, revealing the quantal nature of synaptic transmission. (
  • Action potentials are generated by special types of voltage-gated ion channels embedded in a cell's plasma membrane . (
  • Metabotropic glutamate (mGlu) receptors, which include mGlu1-8 receptors, are a heterogeneous family of G-protein-coupled receptors which function to modulate brain excitability via presynaptic, postsynaptic and glial mechanisms. (
  • Xiong, H & Marshall, KC 1994, ' Angiotensin II depresses glutamate depolarizations and excitatory postsynaptic potentials in locus coeruleus through angiotensin II subtype 2 receptors ', Neuroscience , vol. 62, no. 1, pp. 163-175. (
  • These signals include dipoles gen- erated among others by spiking activity (Rall, 1962), postsynaptic potentials (Mitzdorf, 1985) and fluctuations in the membrane volt- age (Pedemonte et al. (
  • a store of potential energy produced by a greater negative charge on the intracellular side relative to the extracellular side. (
  • Intracellular records from MG somata showed these stimuli evoked broad action potentials whose timing corresponds to this sink. (
  • Castillo J., Katz B. Quantal components of the end-plate potential. (
  • Purpose: Several substances have been shown to potentiate the short-term-facilitated excitatory junctional potentials (EJPs) at neuromuscular junctions (NMJs) of walking limb dactyl opener muscles of the crayfish, Procambarus clarkii and simulans. (
  • In some invertebrates, glutamate is the main excitatory transmitter at the neuromuscular junction. (
  • Moreover, the association of the postsynaptic density protein PSD-95 with TrkB is critical for intact BDNF signaling, and elevated levels of Arc were found to impede PSD-95/TrkB association. (
  • We find that the association of the postsynaptic density protein PSD-95 with TrkB is critical for intact BDNF signaling, and that the high levels of Arc in AS interfere with BDNF-induced recruitment of postsynaptic density protein-95 (PSD-95) and other effectors to TrkB. (