Bulbous enlargement of the growing tip of nerve axons and dendrites. They are crucial to neuronal development because of their pathfinding ability and their role in synaptogenesis.
Renewal or physiological repair of damaged nerve tissue.
A superorder of CEPHALOPODS comprised of squid, cuttlefish, and their relatives. Their distinguishing feature is the modification of their fourth pair of arms into tentacles, resulting in 10 limbs.
The directed transport of ORGANELLES and molecules along nerve cell AXONS. Transport can be anterograde (from the cell body) or retrograde (toward the cell body). (Alberts et al., Molecular Biology of the Cell, 3d ed, pG3)
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.
Neurons which activate MUSCLE CELLS.
The lipid-rich sheath surrounding AXONS in both the CENTRAL NERVOUS SYSTEMS and PERIPHERAL NERVOUS SYSTEM. The myelin sheath is an electrical insulator and allows faster and more energetically efficient conduction of impulses. The sheath is formed by the cell membranes of glial cells (SCHWANN CELLS in the peripheral and OLIGODENDROGLIA in the central nervous system). Deterioration of the sheath in DEMYELINATING DISEASES is a serious clinical problem.
The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.
A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.
Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.
Extensions of the nerve cell body. They are short and branched and receive stimuli from other NEURONS.
Neuroglial cells of the peripheral nervous system which form the insulating myelin sheaths of peripheral axons.
The X-shaped structure formed by the meeting of the two optic nerves. At the optic chiasm the fibers from the medial part of each retina cross to project to the other side of the brain while the lateral retinal fibers continue on the same side. As a result each half of the brain receives information about the contralateral visual field from both eyes.
The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.
A family of proteins that mediate axonal guidance. Semaphorins act as repulsive cues for neuronal GROWTH CONES and bind to receptors on their filopodia. At least 20 different molecules have been described and divided into eight classes based on domain organization and species of origin. Classes 1 and 2 are invertebrate, classes 3-7 are vertebrate, and class V are viral. Semaphorins may be secreted (classes 2, 3, and V), transmembrane (classes 1, 4, 5, and 6), or membrane-anchored (class 7). All semaphorins possess a common 500-amino acid extracellular domain which is critical for receptor binding and specificity, and is also found in plexins and scatter factor receptors. Their C termini are class-specific and may contain additional sequence motifs.
Degeneration of distal aspects of a nerve axon following injury to the cell body or proximal portion of the axon. The process is characterized by fragmentation of the axon and its MYELIN SHEATH.
The prototypical and most well-studied member of the semaphorin family. Semaphorin-3A is an axon-repulsive guidance cue for migrating neurons in the developing nervous system. It has so far been found only in vertebrates, and binds to NEUROPILIN-1/plexin complex receptors on growth cones. Like other class 3 semaphorins, it is a secreted protein.
In tissue culture, hairlike projections of neurons stimulated by growth factors and other molecules. These projections may go on to form a branched tree of dendrites or a single axon or they may be reabsorbed at a later stage of development. "Neurite" may refer to any filamentous or pointed outgrowth of an embryonal or tissue-culture neural cell.
Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.
The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.
Sensory ganglia located on the dorsal spinal roots within the vertebral column. The spinal ganglion cells are pseudounipolar. The single primary branch bifurcates sending a peripheral process to carry sensory information from the periphery and a central branch which relays that information to the spinal cord or brain.
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.
The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium.
The anterior pair of the quadrigeminal bodies which coordinate the general behavioral orienting responses to visual stimuli, such as whole-body turning, and reaching.
Factors which enhance the growth potentialities of sensory and sympathetic nerve cells.
The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.
A nervous tissue specific protein which is highly expressed in NEURONS during development and NERVE REGENERATION. It has been implicated in neurite outgrowth, long-term potentiation, SIGNAL TRANSDUCTION, and NEUROTRANSMITTER release. (From Neurotoxicology 1994;15(1):41-7) It is also a substrate of PROTEIN KINASE C.
Specialized afferent neurons capable of transducing sensory stimuli into NERVE IMPULSES to be transmitted to the CENTRAL NERVOUS SYSTEM. Sometimes sensory receptors for external stimuli are called exteroceptors; for internal stimuli are called interoceptors and proprioceptors.
Transection or severing of an axon. This type of denervation is used often in experimental studies on neuronal physiology and neuronal death or survival, toward an understanding of nervous system disease.
The non-neuronal cells of the nervous system. They not only provide physical support, but also respond to injury, regulate the ionic and chemical composition of the extracellular milieu, participate in the BLOOD-BRAIN BARRIER and BLOOD-RETINAL BARRIER, form the myelin insulation of nervous pathways, guide neuronal migration during development, and exchange metabolites with neurons. Neuroglia have high-affinity transmitter uptake systems, voltage-dependent and transmitter-gated ion channels, and can release transmitters, but their role in signaling (as in many other functions) is unclear.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.
Regularly spaced gaps in the myelin sheaths of peripheral axons. Ranvier's nodes allow saltatory conduction, that is, jumping of impulses from node to node, which is faster and more energetically favorable than continuous conduction.
Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
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 enzyme isolated from horseradish which is able to act as an antigen. It is frequently used as a histochemical tracer for light and electron microscopy. Its antigenicity has permitted its use as a combined antigen and marker in experimental immunology.
Treatment of muscles and nerves under pressure as a result of crush injuries.
The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.
ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.
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.
The entire nerve apparatus, composed of a central part, the brain and spinal cord, and a peripheral part, the cranial and spinal nerves, autonomic ganglia, and plexuses. (Stedman, 26th ed)
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
Loss of functional activity and trophic degeneration of nerve axons and their terminal arborizations following the destruction of their cells of origin or interruption of their continuity with these cells. The pathology is characteristic of neurodegenerative diseases. Often the process of nerve degeneration is studied in research on neuroanatomical localization and correlation of the neurophysiology of neural pathways.
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.
Dimeric cell surface receptor involved in angiogenesis (NEOVASCULARIZATION, PHYSIOLOGICAL) and axonal guidance. Neuropilin-1 is a 140-kDa transmembrane protein that binds CLASS 3 SEMAPHORINS, and several other growth factors. Neuropilin-1 forms complexes with plexins or VEGF RECEPTORS, and binding affinity and specificity are determined by the composition of the neuropilin dimer and the identity of other receptors complexed with it. Neuropilin-1 is expressed in distinct patterns during neural development, complementary to those described for NEUROPILIN-2.
A contactin subtype that plays a role in axon outgrowth, axon fasciculation, and neuronal migration.
The paired caudal parts of the PROSENCEPHALON from which the THALAMUS; HYPOTHALAMUS; EPITHALAMUS; and SUBTHALAMUS are derived.
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)
Refers to animals in the period of time just after birth.
The 1st cranial nerve. The olfactory nerve conveys the sense of smell. It is formed by the axons of OLFACTORY RECEPTOR NEURONS which project from the olfactory epithelium (in the nasal epithelium) to the OLFACTORY BULB.
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.
Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.
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.
An exotic species of the family CYPRINIDAE, originally from Asia, that has been introduced in North America. They are used in embryological studies and to study the effects of certain chemicals on development.
Use of electric potential or currents to elicit biological responses.
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.
The nervous system outside of the brain and spinal cord. The peripheral nervous system has autonomic and somatic divisions. The autonomic nervous system includes the enteric, parasympathetic, and sympathetic subdivisions. The somatic nervous system includes the cranial and spinal nerves and their ganglia and the peripheral sensory receptors.
A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.
A phylum of the kingdom Metazoa. Mollusca have soft, unsegmented bodies with an anterior head, a dorsal visceral mass, and a ventral foot. Most are encased in a protective calcareous shell. It includes the classes GASTROPODA; BIVALVIA; CEPHALOPODA; Aplacophora; Scaphopoda; Polyplacophora; and Monoplacophora.
Branch-like terminations of NERVE FIBERS, sensory or motor NEURONS. Endings of sensory neurons are the beginnings of afferent pathway to the CENTRAL NERVOUS SYSTEM. Endings of motor neurons are the terminals of axons at the muscle cells. Nerve endings which release neurotransmitters are called PRESYNAPTIC TERMINALS.
Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.
A GLYCOINOSITOL PHOSPHOLIPID MEMBRANE ANCHOR-containing ephrin with a high affinity for the EPHA3 RECEPTOR. Early in embryogenesis it is expressed at high levels in the MESENCEPHALON; SOMITES; branchial arches, and LIMB BUDS.
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.
A large family of receptor protein-tyrosine kinases that are structurally-related. The name of this family of proteins derives from original protein Eph (now called the EPHA1 RECEPTOR), which was named after the cell line it was first discovered in: Erythropoietin-Producing human Hepatocellular carcinoma cell line. Members of this family have been implicated in regulation of cell-cell interactions involved in nervous system patterning and development.
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.
MYELIN-specific proteins that play a structural or regulatory role in the genesis and maintenance of the lamellar MYELIN SHEATH structure.
Involuntary contraction of the muscle fibers innervated by a motor unit. Fasciculations can often by visualized and take the form of a muscle twitch or dimpling under the skin, but usually do not generate sufficient force to move a limb. They may represent a benign condition or occur as a manifestation of MOTOR NEURON DISEASE or PERIPHERAL NERVOUS SYSTEM DISEASES. (Adams et al., Principles of Neurology, 6th ed, p1294)
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.
A GLYCOINOSITOL PHOSPHOLIPID MEMBRANE ANCHOR containing ephrin found in developing tectum. It has been shown to mediate the bundling of cortical axons and repel the axonal growth of retinal ganglia axons. It is found in a variety of adult tissues of BRAIN; HEART; and KIDNEY.
A class of large neuroglial (macroglial) cells in the central nervous system. Oligodendroglia may be called interfascicular, perivascular, or perineuronal (not the same as SATELLITE CELLS, PERINEURONAL of GANGLIA) according to their location. They form the insulating MYELIN SHEATH of axons in the central nervous system.
Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.
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.
The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.
Penetrating and non-penetrating injuries to the spinal cord resulting from traumatic external forces (e.g., WOUNDS, GUNSHOT; WHIPLASH INJURIES; etc.).
The 4th cranial nerve. The trochlear nerve carries the motor innervation of the superior oblique muscles of the eye.
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.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
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.
Formation of NEURONS which involves the differentiation and division of STEM CELLS in which one or both of the daughter cells become neurons.
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.
Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.
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.
Elements of limited time intervals, contributing to particular results or situations.
Transmembrane receptor for CLASS 3 SEMAPHORINS and several vascular endothelial growth factor isoforms. Neuropilin-2 functions either as a homodimer or as a heterodimer with NEUROPILIN-1. The binding affinity of neuropilin-2 varies for different class 3 semaphorin isoforms and is dependent on the composition of the dimer. The protein also forms receptor complexes with plexins and with VEGF RECEPTORS, which alters the binding characteristics of the receptor.
Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.
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.
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).
A class of marine annelids including sandworms, tube worms, clamworms, and fire worms. It includes also the genus Myxicola infundibulum.
The dorsal portion or roof of the midbrain which is composed of two pairs of bumps, the INFERIOR COLLICULI and the SUPERIOR COLLICULI. These four colliculi are also called the quadrigeminal bodies (TECTUM MESENCEPHALI). They are centers for visual sensorimotor integration.
Clusters of multipolar neurons surrounded by a capsule of loosely organized CONNECTIVE TISSUE located outside the CENTRAL NERVOUS SYSTEM.
Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.
Neurons in the OLFACTORY EPITHELIUM with proteins (RECEPTORS, ODORANT) that bind, and thus detect, odorants. These neurons send their DENDRITES to the surface of the epithelium with the odorant receptors residing in the apical non-motile cilia. Their unmyelinated AXONS synapse in the OLFACTORY BULB of the BRAIN.
The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.
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.
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.
Proteins from the nematode species CAENORHABDITIS ELEGANS. The proteins from this species are the subject of scientific interest in the area of multicellular organism MORPHOGENESIS.
Cell adhesion molecule involved in a diverse range of contact-mediated interactions among neurons, astrocytes, oligodendrocytes, and myotubes. It is widely but transiently expressed in many tissues early in embryogenesis. Four main isoforms exist, including CD56; (ANTIGENS, CD56); but there are many other variants resulting from alternative splicing and post-translational modifications. (From Pigott & Power, The Adhesion Molecule FactsBook, 1993, pp115-119)
A species of nematode that is widely used in biological, biochemical, and genetic studies.
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
The synapse between a neuron and a muscle.
STILBENES with AMIDINES attached.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A technique in which electric pulses of intensity in kilovolts per centimeter and of microsecond-to-millisecond duration cause a temporary loss of the semipermeability of CELL MEMBRANES, thus leading to ion leakage, escape of metabolites, and increased uptake by cells of drugs, molecular probes, and DNA.
A microtubule subunit protein found in large quantities in mammalian brain. It has also been isolated from SPERM FLAGELLUM; CILIA; and other sources. Structurally, the protein is a dimer with a molecular weight of approximately 120,000 and a sedimentation coefficient of 5.8S. It binds to COLCHICINE; VINCRISTINE; and VINBLASTINE.
Compounds that contain three methine groups. They are frequently used as cationic dyes used for differential staining of biological materials.
In invertebrate zoology, a lateral lobe of the FOREBRAIN in certain ARTHROPODS. In vertebrate zoology, either of the corpora bigemina of non-mammalian VERTEBRATES. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1329)
An enzyme that catalyzes reversibly the transfer of the adenylyl moiety of ATP to the phosphoryl group of NMN to form NAD+ and pyrophosphate. The enzyme is found predominantly in the nuclei and catalyzes the final reaction in the major pathway for the biosynthesis of NAD in mammals. EC 2.7.7.1.
The largest and uppermost of the paravertebral sympathetic ganglia.
Diseases characterized by loss or dysfunction of myelin in the central or peripheral nervous system.
Proteins obtained from the ZEBRAFISH. Many of the proteins in this species have been the subject of studies involving basic embryological development (EMBRYOLOGY).
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.
An enzyme that catalyzes the eliminative degradation of polysaccharides containing 1,4-beta-D-hexosaminyl and 1,3-beta-D-glucuronosyl or 1,3-alpha-L-iduronosyl linkages to disaccharides containing 4-deoxy-beta-D-gluc-4-enuronosyl groups. (Enzyme Nomenclature, 1992)
Injuries to the optic nerve induced by a trauma to the face or head. These may occur with closed or penetrating injuries. Relatively minor compression of the superior aspect of orbit may also result in trauma to the optic nerve. Clinical manifestations may include visual loss, PAPILLEDEMA, and an afferent pupillary defect.
A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.
Mice which carry mutant genes for neurologic defects or abnormalities.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.
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.
Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.
The posterior of the three primitive cerebral vesicles of an embryonic brain. It consists of myelencephalon, metencephalon, and isthmus rhombencephali from which develop the major BRAIN STEM components, such as MEDULLA OBLONGATA from the myelencephalon, CEREBELLUM and PONS from the metencephalon, with the expanded cavity forming the FOURTH VENTRICLE.
Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.
Differentiated tissue of the central nervous system composed of NERVE CELLS, fibers, DENDRITES, and specialized supporting cells.
Common name for Carassius auratus, a type of carp (CARPS).
The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.
The anterior of the three primitive cerebral vesicles of the embryonic brain arising from the NEURAL TUBE. It subdivides to form DIENCEPHALON and TELENCEPHALON. (Stedmans Medical Dictionary, 27th ed)
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.
The anterior subdivision of the embryonic PROSENCEPHALON or the corresponding part of the adult prosencephalon that includes the cerebrum and associated structures.
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)
Pathologic changes that occur in the axon and cell body of a neuron proximal to an axonal lesion. The process is characterized by central chromatolysis which features flattening and displacement of the nucleus, loss of Nissl bodies, and cellular edema. Central chromatolysis primarily occurs in lower motor neurons.
The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.
Specialized cells in the invertebrates that detect and transduce light. They are predominantly rhabdomeric with an array of photosensitive microvilli. Illumination depolarizes invertebrate photoreceptors by stimulating Na+ influx across the plasma membrane.
A dense intricate feltwork of interwoven fine glial processes, fibrils, synaptic terminals, axons, and dendrites interspersed among the nerve cells in the gray matter of the central nervous system.
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.
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.
A large subphylum of mostly marine ARTHROPODS containing over 42,000 species. They include familiar arthropods such as lobsters (NEPHROPIDAE), crabs (BRACHYURA), shrimp (PENAEIDAE), and barnacles (THORACICA).
Injuries to the PERIPHERAL NERVES.
An eph family receptor found primarily in differentiated neuronal tissues. Several isoforms of EphA5 receptor occur due to multiple alternative RNA splicing. The protein is prominently expressed in the NEURONS of the LIMBIC SYSTEM during development and throughout adult life, suggesting its role in the plasticity of limbic structure and function.
An eph family receptor found in variety of tissues including BRAIN. During embryogenesis, EphA4 receptor exhibits a diverse spatial and temporal patterns of expression suggesting its role in multiple developmental processes.
Disease or damage involving the SCIATIC NERVE, which divides into the PERONEAL NERVE and TIBIAL NERVE (see also PERONEAL NEUROPATHIES and TIBIAL NEUROPATHY). Clinical manifestations may include SCIATICA or pain localized to the hip, PARESIS or PARALYSIS of posterior thigh muscles and muscles innervated by the peroneal and tibial nerves, and sensory loss involving the lateral and posterior thigh, posterior and lateral leg, and sole of the foot. The sciatic nerve may be affected by trauma; ISCHEMIA; COLLAGEN DISEASES; and other conditions. (From Adams et al., Principles of Neurology, 6th ed, p1363)
The resection or removal of the nerve to an organ or part. (Dorland, 28th ed)
Any of several ways in which living cells of an organism communicate with one another, whether by direct contact between cells or by means of chemical signals carried by neurotransmitter substances, hormones, and cyclic AMP.
Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.
Annelids of the class Hirudinea. Some species, the bloodsuckers, may become temporarily parasitic upon animals, including man. Medicinal leeches (HIRUDO MEDICINALIS) have been used therapeutically for drawing blood since ancient times.
The number of CELLS of a specific kind, usually measured per unit volume or area of sample.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
Motor neurons which activate the contractile regions of intrafusal SKELETAL MUSCLE FIBERS, thus adjusting the sensitivity of the MUSCLE SPINDLES to stretch. Gamma motor neurons may be "static" or "dynamic" according to which aspect of responsiveness (or which fiber types) they regulate. The alpha and gamma motor neurons are often activated together (alpha gamma coactivation) which allows the spindles to contribute to the control of movement trajectories despite changes in muscle length.
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.
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.
Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
The founding member of the EPH FAMILY RECEPTORS. It was first cloned from an erythropoietin-producing human hepatocellular carcinoma cell line and is highly conserved among many mammalian species. Overproduction of the EphA1 receptor is associated with tumors and tumor cells of epithelial origin. It is also expressed at high levels in LIVER; LUNG; and KIDNEY; which is in contrast to many other members of the Eph receptor that are found primarily in tissues of the nervous system.
A family of membrane-associated proteins responsible for the attachment of the cytoskeleton. Erythrocyte-related isoforms of ankyrin attach the SPECTRIN cytoskeleton to a transmembrane protein (ANION EXCHANGE PROTEIN 1, ERYTHROCYTE) in the erythrocyte plasma membrane. Brain-related isoforms of ankyrin also exist.
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 myelin protein found in the periaxonal membrane of both the central and peripheral nervous systems myelin sheaths. It binds to cells surface receptors found on AXONS and may regulate cellular interactions between MYELIN and AXONS.
The function of opposing or restraining the excitation of neurons or their target excitable cells.
Plant-eating orthopterans having hindlegs adapted for jumping. There are two main families: Acrididae and Romaleidae. Some of the more common genera are: Melanoplus, the most common grasshopper; Conocephalus, the eastern meadow grasshopper; and Pterophylla, the true katydid.
Cell adhesion molecules that mediate neuron-neuron adhesion and neuron-astrocyte adhesion. They are expressed on neurons and Schwann cells, but not astrocytes and are involved in neuronal migration, neurite fasciculation, and outgrowth. Ng-CAM is immunologically and structurally distinct from NCAM.
High molecular weight proteins found in the MICROTUBULES of the cytoskeletal system. Under certain conditions they are required for TUBULIN assembly into the microtubules and stabilize the assembled microtubules.
The most common inhibitory neurotransmitter in the central nervous system.
Cell surface molecules on cells of the immune system that specifically bind surface molecules or messenger molecules and trigger changes in the behavior of cells. Although these receptors were first identified in the immune system, many have important functions elsewhere.
The superficial GRAY MATTER of the CEREBELLUM. It consists of two main layers, the stratum moleculare and the stratum granulosum.
Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.
Methods used to label and follow the course of NEURAL PATHWAYS by AXONAL TRANSPORT of injected NEURONAL TRACT-TRACERS.
A transmembrane domain containing ephrin. Although originally found to be specific for the EPHB3 RECEPTOR it has since been shown to bind a variety of EPH FAMILY RECEPTORS. During embryogenesis ephrin-B3 is expressed at high levels in the ventral neural tube. In adult tissues, it is found primarily in the BRAIN and HEART.
Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.
Neurons which send impulses peripherally to activate muscles or secretory cells.
Contractile tissue that produces movement in animals.
Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.
Family of large marine CRUSTACEA, in the order DECAPODA. These are called clawed lobsters because they bear pincers on the first three pairs of legs. The American lobster and Cape lobster in the genus Homarus are commonly used for food.
Surface ligands, usually glycoproteins, that mediate cell-to-cell adhesion. Their functions include the assembly and interconnection of various vertebrate systems, as well as maintenance of tissue integration, wound healing, morphogenic movements, cellular migrations, and metastasis.
An eph family receptor that is found primarily in adult BRAIN and variety of tissues in the developing embryo tissues. During embryonic development high levels of EphA3 receptor expression is seen in the nervous system and coincides with neuronal cell migration, suggesting a role for this protein in axonal pathfinding.
A member of the immunoglobulin superfamily of neuronal cell adhesion molecules that is required for proper nervous system development. Neural cell adhesion molecule L1 consists of six Ig domains, five fibronectin domains, a transmembrane region and an intracellular domain. Two splicing variants are known: a neuronal form that contains a four-amino acid RSLE sequence in the cytoplasmic domain, and a non-neuronal form that lacks the RSLE sequence. Mutations in the L1 gene result in L1 disease. Neural cell adhesion molecule L1 is predominantly expressed during development in neurons and Schwann cells; involved in cell adhesion, neuronal migration, axonal growth and pathfinding, and myelination.
Twelve pairs of nerves that carry general afferent, visceral afferent, special afferent, somatic efferent, and autonomic efferent fibers.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
Either of two extremities of four-footed non-primate land animals. It usually consists of a FEMUR; TIBIA; and FIBULA; tarsals; METATARSALS; and TOES. (From Storer et al., General Zoology, 6th ed, p73)
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
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.
A member of the nerve growth factor family of trophic factors. In the brain BDNF has a trophic action on retinal, cholinergic, and dopaminergic neurons, and in the peripheral nervous system it acts on both motor and sensory neurons. (From Kendrew, The Encyclopedia of Molecular Biology, 1994)
Study of intracellular distribution of chemicals, reaction sites, enzymes, etc., by means of staining reactions, radioactive isotope uptake, selective metal distribution in electron microscopy, or other methods.
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.
Structural abnormalities of the central or peripheral nervous system resulting primarily from defects of embryogenesis.
A class of nerve fibers as defined by their nerve sheath arrangement. The AXONS of the unmyelinated nerve fibers are small in diameter and usually several are surrounded by a single MYELIN SHEATH. They conduct low-velocity impulses, and represent the majority of peripheral sensory and autonomic fibers, but are also found in the BRAIN and SPINAL CORD.
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.
Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.
The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.
Recording serial images of a process at regular intervals spaced out over a longer period of time than the time in which the recordings will be played back.
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.
The output neurons of the cerebellar cortex.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
Substances used to identify the location and to characterize the types of NEURAL PATHWAYS.
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 5th and largest cranial nerve. The trigeminal nerve is a mixed motor and sensory nerve. The larger sensory part forms the ophthalmic, mandibular, and maxillary nerves which carry afferents sensitive to external or internal stimuli from the skin, muscles, and joints of the face and mouth and from the teeth. Most of these fibers originate from cells of the TRIGEMINAL GANGLION and project to the TRIGEMINAL NUCLEUS of the brain stem. The smaller motor part arises from the brain stem trigeminal motor nucleus and innervates the muscles of mastication.
The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot.
The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.
NERVE GROWTH FACTOR is the first of a series of neurotrophic factors that were found to influence the growth and differentiation of sympathetic and sensory neurons. It is comprised of alpha, beta, and gamma subunits. The beta subunit is responsible for its growth stimulating activity.
A neurotrophic factor involved in regulating the survival of visceral and proprioceptive sensory neurons. It is closely homologous to nerve growth factor beta and BRAIN-DERIVED NEUROTROPHIC FACTOR.

Morphogenesis of callosal arbors in the parietal cortex of hamsters. (1/10970)

The morphogenesis of callosal axons originating in the parietal cortex was studied by anterograde labeling with Phaseolus lectin or biocytin injected in postnatal (P) hamsters aged 7-25 days. Some labeled fibers were serially reconstructed. At P7, some callosal fibers extended as far as the contralateral rhinal fissure, with simple arbors located in the homotopic region of the opposite cortical gray matter, and two or three unbranched sprouts along their trajectory. From P7 to P13, the homotopic arbors became more complex, with branches focused predominantly, but not exclusively, in the supra- and infragranular layers of the homotopic region. Simultaneously, the lateral extension of the trunk axon in the white matter became shorter, finally disappearing by P25. Arbors in the gray matter were either bilaminar (layers 2/3 and 5) or supragranular. A heterotopic projection to the lateral cortex was consistently seen at all ages; the heterotopic arbors follow a similar sequence of events to that seen in homotopic regions. These observations document that callosal axons undergo regressive tangential remodeling during the first postnatal month, as the lateral extension of the trunk fiber gets eliminated. Radially, however, significant arborization occurs in layer-specific locations. The protracted period of morphogenesis suggests a correspondingly long plastic period for this system of cortical fibers.  (+info)

Trans-synaptically induced bursts in regular spiking non-pyramidal cells in deep layers of the cat motor cortex. (2/10970)

In deep layers of the cat motor cortex, we have investigated the properties of neurons displaying trans-synaptically induced bursts. In in vivo experiments, extracellularly recorded burst neurons were separated into two subtypes based on their dependence on stimulation sites, the medullary pyramid or the ventrolateral (VL) thalamic nucleus, from which bursts of 10-20 spikes were triggered. The spike amplitude attenuation and frequency adaptation during a burst were more prominent in pyramid-dependent burst neurons than in VL-dependent burst neurons. Intracellular recordings in in vivo experiments revealed that pyramid-dependent bursts emerged from a long-lasting depolarization, while each spike during a VL-dependent burst was narrow in half-width and was followed by a fast AHP, similar to fast spiking neurons. In in vitro slice experiments, intracellular recordings were obtained from neurons that displayed a burst of attenuated spikes emerging from a long-lasting depolarization, and were also obtained from fast spiking neurons. They were morphologically recovered to be multipolar cells with sparsely spiny dendrites and local axonal networks, suggesting that they are inhibitory interneurons. The multipolar neurons displaying bursts of attenuated spikes may mediate the recurrent inhibition of pyramidal tract cells.  (+info)

Central peptidergic neurons are hyperactive during collateral sprouting and inhibition of activity suppresses sprouting. (3/10970)

Little is known regarding the effect of chronic changes in neuronal activity on the extent of collateral sprouting by identified CNS neurons. We have investigated the relationship between activity and sprouting in oxytocin (OT) and vasopressin (VP) neurons of the hypothalamic magnocellular neurosecretory system (MNS). Uninjured MNS neurons undergo a robust collateral-sprouting response that restores the axon population of the neural lobe (NL) after a lesion of the contralateral MNS (). Simultaneously, lesioned rats develop chronic urinary hyperosmolality indicative of heightened neurosecretory activity. We therefore tested the hypothesis that sprouting MNS neurons are hyperactive by measuring changes in cell and nuclear diameters, OT and VP mRNA pools, and axonal cytochrome oxidase activity (COX). Each of these measures was significantly elevated during the period of most rapid axonal growth between 1 and 4 weeks after the lesion, confirming that both OT and VP neurons are hyperactive while undergoing collateral sprouting. In a second study the hypothesis that chronic inhibition of neuronal activity would interfere with the sprouting response was tested. Chronic hyponatremia (CH) was induced 3 d before the hypothalamic lesion and sustained for 4 weeks to suppress neurosecretory activity. CH abolished the lesion-induced increases in OT and VP mRNA pools and virtually eliminated measurable COX activity in MNS terminals. Counts of the total number of axon profiles in the NL revealed that CH also prevented axonal sprouting from occurring. These results are consistent with the hypothesis that increased neuronal activity is required for denervation-induced collateral sprouting to occur in the MNS.  (+info)

Somatic recording of GABAergic autoreceptor current in cerebellar stellate and basket cells. (4/10970)

Patch-clamp recordings were performed from stellate and basket cells in rat cerebellar slices. Under somatic voltage clamp, short depolarizing pulses were applied to elicit action potentials in the axon. After the action potential, a bicuculline- and Cd2+-sensitive current transient was observed. A similar response was obtained when eliciting axonal firing by extracellular stimulation. With an isotonic internal Cl- solution, the peak amplitude of this current varied linearly with the holding potential, yielding an extrapolated reversal potential of -20 to 0 mV. Unlike synaptic or autaptic GABAergic currents obtained in the same preparation, the current transient had a slow rise-time and a low variability between trials. This current was blocked when 10 mM BAPTA was included in the recording solution. In some experiments, the current transient elicited axonal action potentials. The current transient was reliably observed in animals aged 12-15 d, with a mean amplitude of 82 pA at -70 mV, but was small and rare in the age group 29-49 d. Numerical simulations could account for all properties of the current transient by assuming that an action potential activates a distributed GABAergic conductance in the axon. The actual conductance is probably restricted to release sites, with an estimated mean presynaptic current response of 10 pA per site (-70 mV, age 12-15 d). We conclude that in developing rats, stellate and basket cell axons have a high density of GABAergic autoreceptors and that a sizable fraction of the corresponding current can be measured from the soma.  (+info)

The amyloid precursor protein interacts with Go heterotrimeric protein within a cell compartment specialized in signal transduction. (5/10970)

The function of the beta-amyloid protein precursor (betaAPP), a transmembrane molecule involved in Alzheimer pathologies, is poorly understood. We recently reported the presence of a fraction of betaAPP in cholesterol and sphingoglycolipid-enriched microdomains (CSEM), a caveolae-like compartment specialized in signal transduction. To investigate whether betaAPP actually interferes with cell signaling, we reexamined the interaction between betaAPP and Go GTPase. In strong contrast with results obtained with reconstituted phospholipid vesicles (Okamoto et al., 1995), we find that incubating total neuronal membranes with 22C11, an antibody that recognizes an N-terminal betaAPP epitope, reduces high-affinity Go GTPase activity. This inhibition is specific of Galphao and is reproduced, in the absence of 22C11, by the addition of the betaAPP C-terminal domain but not by two distinct mutated betaAPP C-terminal domains that do not bind Galphao. This inhibition of Galphao GTPase activity by either 22C11 or wild-type betaAPP cytoplasmic domain suggests that intracellular interactions between betaAPP and Galphao could be regulated by extracellular signals. To verify whether this interaction is preserved in CSEM, we first used biochemical, immunocytochemical, and ultrastructural techniques to unambiguously confirm the colocalization of Galphao and betaAPP in CSEM. We show that inhibition of basal Galphao GTPase activity also occurs within CSEM and correlates with the coimmunoprecipitation of Galphao and betaAPP. The regulation of Galphao GTPase activity by betaAPP in a compartment specialized in signaling may have important consequences for our understanding of the physiopathological functions of betaAPP.  (+info)

Cellular sites for dynorphin activation of kappa-opioid receptors in the rat nucleus accumbens shell. (6/10970)

The nucleus accumbens (Acb) is prominently involved in the aversive behavioral aspects of kappa-opioid receptor (KOR) agonists, including its endogenous ligand dynorphin (Dyn). We examined the ultrastructural immunoperoxidase localization of KOR and immunogold labeling of Dyn to determine the major cellular sites for KOR activation in this region. Of 851 KOR-labeled structures sampled from a total area of 10,457 microm2, 63% were small axons and morphologically heterogenous axon terminals, 31% of which apposed Dyn-labeled terminals or also contained Dyn. Sixty-eight percent of the KOR-containing axon terminals formed punctate-symmetric or appositional contacts with unlabeled dendrites and spines, many of which received convergent input from terminals that formed asymmetric synapses. Excitatory-type terminals that formed asymmetric synapses with dendritic spines comprised 21% of the KOR-immunoreactive profiles. Dendritic spines within the neuropil were the major nonaxonal structures that contained KOR immunoreactivity. These spines also received excitatory-type synapses from unlabeled terminals and were apposed by Dyn-containing terminals. These results provide ultrastructural evidence that in the Acb shell (AcbSh), KOR agonists play a primary role in regulating the presynaptic release of Dyn and other neuromodulators that influence the output of spiny neurons via changes in the presynaptic release of or the postsynaptic responses to excitatory amino acids. The cellular distribution of KOR complements those described previously for the reward-associated mu- and delta-opioid receptors in the Acb shell.  (+info)

even-skipped determines the dorsal growth of motor axons in Drosophila. (7/10970)

Axon pathfinding and target choice are governed by cell type-specific responses to external cues. Here, we show that in the Drosophila embryo, motorneurons with targets in the dorsal muscle field express the homeobox gene even-skipped and that this expression is necessary and sufficient to direct motor axons into the dorsal muscle field. Previously, it was shown that motorneurons projecting to ventral targets express the LIM homeobox gene islet, which is sufficient to direct axons to the ventral muscle field. Thus, even-skipped complements the function of islet, and together these two genes constitute a bimodal switch regulating axonal growth and directing motor axons to ventral or to dorsal regions of the muscle field.  (+info)

Prior exposure to neurotrophins blocks inhibition of axonal regeneration by MAG and myelin via a cAMP-dependent mechanism. (8/10970)

MAG is a potent inhibitor of axonal regeneration. Here, inhibition by MAG, and myelin in general, is blocked if neurons are exposed to neurotrophins before encountering the inhibitor; priming cerebellar neurons with BDNF or GDNF, but not NGF, or priming DRG neurons with any of these neurotrophins blocks inhibition by MAG/myelin. Dibutyryl cAMP also overcomes inhibition by MAG/myelin, and cAMP is elevated by neurotrophins. A PKA inhibitor present during priming abrogates the block of inhibition. Finally, if neurons are exposed to MAG/myelin and neurotrophins simultaneously, but with the Gi protein inhibitor, inhibition is blocked. We suggest that priming neurons with particular neurotrophins elevates cAMP and activates PKA, which blocks subsequent inhibition of regeneration and that priming is required because MAG/myelin activates a Gi protein, which blocks increases in cAMP. This is important for encouraging axons to regrow in vivo.  (+info)

The transcript encoding translationally controlled tumor protein (Tctp), a molecule correlated with aggressive breast cancers, was identified among the most abundant in genome-wide screens of axons, suggesting that Tctp is important in neurons. Here, we tested the role of Tctp in retinal axon development in Xenopus laevis. We report that Tctp deficiency results in stunted and splayed retinotectal projections that fail to innervate the optic tectum at the normal developmental time due to impaired axon extension. Tctp-deficient axons exhibit defects associated with mitochondrial dysfunction and we show that Tctp interacts in the axonal compartment with myeloid cell leukemia 1 (Mcl1), a pro-survival member of the Bcl-2 family. Mcl1 knockdown gives rise to similar axon misprojection phenotypes, and we provide evidence that Tctps anti-apoptotic activity is necessary for the normal development of the retinotectal projection. The findings suggest that Tctp supports the development of the retinotectal ...
Pathogenesis of the autoimmune disease multiple sclerosis (MS) is associated with progressive deterioration of the myelin sheath surrounding neuronal axons; however, axon damage may also contribute to MS-associated neurodegeneration. Nikić et al. used in vivo imaging and electron microscopy to examine axon damage in a mouse model of MS (EAE, experimental autoimmune encephalitis). In EAE mice, swelling in discrete sites on axons was observed, which was then followed by axon fragmentation. In many cases, damaged axons retained myelin; in some cases, axon damage was reversible. Axon damage was preceded by mitochondrial pathology, which was associated with the presence of microglia and the production of reactive oxygen and nitrogen species. Induction of oxidative or nitrosative stress was sufficient to induce mitochondrial pathology and axon damage in normal mice, and their blockade in EAE mice alleviated axon damage. Lesion biopsies from MS patients also showed similar axon (above, right) and ...
TY - JOUR. T1 - Dystroglycan is a scaffold for extracellular axon guidance decisions. AU - Lindenmaier, L. Bailey. AU - Parmentier, Nicolas. AU - Guo, Caiying. AU - Tissir, Fadel. AU - Wright, Kevin. PY - 2019/2/13. Y1 - 2019/2/13. N2 - Axon guidance requires interactions between extracellular signaling molecules and transmembrane receptors, but how appropriate context-dependent decisions are coordinated outside the cell remains unclear. Here we show that the transmembrane glycoprotein Dystroglycan interacts with a changing set of environmental cues that regulate the trajectories of extending axons throughout the mammalian brain and spinal cord. Dystroglycan operates primarily as an extracellular scaffold during axon guidance, as it functions non-cell autonomously and does not require signaling through its intracellular domain. We identify the transmembrane receptor Celsr3/Adgrc3 as a binding partner for Dystroglycan, and show that this interaction is critical for specific axon guidance events ...
Axonal localization of viral membrane proteins promoted by Us9 missense mutants correlates with degree of anterograde spread in the rodent nervous system. Neuro
The eye is a peripheral outpost of the central nervous system (CNS) where the retinal ganglion cells (RGCs) reside. RGC axons navigate to their targets in a remarkably stereotyped and error-free manner and it is this process of directed growth that underlies the complex organization of the adult brain. The RGCs are the only retinal neurons to project into the brain and their peripheral location makes them an unusually accessible population of projection neurons for experiments involving in vivo gene transfer, anatomical tracing, transplantation and in vitro culture. In this paper, we review recent findings that have contributed to our understanding of some of the guidance decisions that axons make in the developing visual system. We look at two choice points in the pathway, the optic nerve head (onh) and the midline chiasm, and discuss evidence that supports the idea that key molecules in guiding axon growth at these junctures are netrin-1 (onh) and ephrin-B (chiasm). In the optic tectum where RGC axon
Proteins characteristic of growing axons often fail to be induced or transported along axons that have been interrupted far from their cell bodies in the adult mammalian CNS. Here, we inquire whether long axons in the mammalian CNS can support efficient axonal transport and deposition of one such protein, GAP-43, when the protein is induced in neuron cell bodies. We have used immunocytochemistry to follow the fate of GAP-43 in dorsal column axons ascending the rat spinal cord from dorsal column axons ascending the rat spinal cord from dorsal root ganglion (DRG) neurons, after synthesis of the protein is induced in these cells by peripheral nerve injury. Sciatic nerve lesions do lead to an accumulation of GAP-43 in dorsal column axons derived from the lumbar DRG. However, in distal segments of these CNS axons, accumulation of GAP-43 is apparent only after a delay of 1-2 weeks, in contrast to its rapid accumulation in axon segments within the PNS environment, suggesting that deposition and ...
zag-1 activity establishes several neuronal characteristics, such as cell position, axonal structure and gene-expression profile. Although zag-1 mutations confer various defects on sensory, motor and interneurons, common or related phenotypes are evident. These include the absence of stereotypic axon branches and upregulation of neurotransmitter biosynthetic and reuptake genes. zag-1 functions less to define neuron identity per se and more to generate features characteristic of a particular type of neuron. The specificity and selectivity of zag-1 phenotypes for each neuron type suggests that zag-1 acts in combination with other cell-type-specific factors to control differentiation.. SRA-6 is a candidate chemosensory receptor, based on its predicted seven transmembrane domain topology and expression in amphid sensory neurons ASH and ASI (Troemel et al., 1995). sra-6::gfp provides an ideal indicator of PVQ development and differentiation, although sra-6 function in interneuron PVQ is unclear. ...
This is a message to people interested (or potentially interested) in the development of the Drosophila motor axon system and CNS: I recently constructed a World Wide Web site (linked to our homepage, which is http://www.caltech.edu/~zinn/ ) on motor axon development in flies. This consists at present of a gallery of high-resolution Photoshop images (,35 images of antibody-stained embryos photographed with DIC optics, and several diagrams) of the neuromuscular system in embryos, with accompanying text. Most of the images in the current version are of wild-type embryos stained with the 1D4 antibody against Fasciclin II, which specifically labels motor axons (Van Vactor et al., Cell 73, 1137-1153 (1993)). The same segments are shown in several focal planes, so that the viewer can see the details of the pathways as if they were examining an actual embryo under the microscope. There are also embryos double-stained for PNS, muscle, and tracheal markers, so that motor axon development can be keyed to ...
In contrast to peripheral nerves, damaged axons of the mammalian brain and spinal cord rarely regenerate. Although the nature of the neuronal environment, particularly inhibitory molecules on myelin and in glial scar tissue, can partially explain the lack of regeneration in the CNS, intrinsic neuronal factors also have an influence. Intrinsic influences on axon growth are neuronal age (Lagunowich et al., 1992; Li et al., 1995), neuronal cell type (Benfey et al., 1985; Rossi et al., 2001), distance of axotomy from the cell body (Fernandes et al., 1999), and conditioning (McQuarrie, 1978; Neumann and Woolf, 1999). Thus, embryonic axons grow through environments that ordinarily block regeneration, some axons mount a vigorous regenerative response whereas some never regenerate, axons cut close to the cell body show a greater regenerative response than those cut more distally, and axons may regenerate with greater vigor if they have been damaged some days previously.. For successful regeneration, the ...
One of the most challenging problems in biology is to understand how the billions of neurons in the mammalian nervous system wire up to form functional neural circuits that underlie all behaviour. This has been one of the most intensely studied areas of developmental neurobiology in the past, and a number of important proteins have been identified that instruct axons to project to their specific target regions (so called axon guidance proteins).. Our current work focuses on how axon guidance proteins are detected by receptor proteins on growing axons, how these receptors signal and how they are regulated by for example endocytosis or proteolytic cleavage. Remarkably, our nervous system contains billions of connections but no more than a hundred axon guidance proteins. How can this relatively small number of proteins set up the wiring of a disproportionally large number of connections with many different characteristics such as trajectories or synaptic partners? Evidence is emerging that the ...
Nakamura, T., et al. (2017). Novel role of Rac-Mid1 signaling in medial cerebellar development. Development 144(10): 1863-1875. PubMed ID: 28512198 Nakaya, Y., Kuroda, S., Katagiri, Y. T., Kaibuchi, K. and Takahashi Y. (2004). Mesenchymal-epithelial transition during somitic segmentation is regulated by differential roles of Cdc42 and Rac1. Dev Cell. 7(3): 425-38. 15363416 Newsome, T. P., Schmidt, S., Dietzl, G., Keleman, K., Asling, B., Debant, A., and Dickson, B. J. (2000). Trio combines with Dock to regulate Pak activity during photoreceptor axon pathfinding in Drosophila. Cell 101: 283-94. PubMed Citation: 10847683 Ng, J., et al. (2002). Rac GTPases control axon growth, guidance and branching. Nature 416: 442-447. 11919635 Ng, J. and Luo, L. (2004). Rho GTPases regulate axon growth through convergent and divergent signaling pathways. Neuron 44: 779-793. 15572110 Ng, J. (2008). TGF-β signals regulate axonal development through distinct Smad-independent mechanisms. Development 135(24): ...
While commissural axons pathways are absent in comm mutants, other aspects of CNS development appear normal, including formation of longitudinal axon pathways, nerve roots, peripheral axon pathways, and peripheral sensory neurons. The mutant phenotype appears to be quite specific to the midline of the CNS, since the pattern for cuticle, segmentation, and muscles are normal. The normal axon projection of the ventral unpaired medial neurons (VUMs) is particularly interesting because the VUM cell bodies are located at the midline and extend growth cones that bifurcate and project away from the midline and toward the intersegmental nerve root. The fact that this happens in a relatively normal fashion in comm mutants suggests that there is no physical barrier preventing growth cones from extending near the midline. Later in embryogenesis, in the absence of commissural axon pathways and their surrounding nonneuronal cells holding the two sides of the CNS together, the CNS starts to unzip as it splits ...
Developing motoneurons in zebrafish embryos follow a stereotyped sequence of axonal outgrowth and accurately project their axons to cell-specific target muscles. During axonal pathfinding, an identified motoneuron pioneers the peripheral motor pathway. Growth cones of later motoneurons interact with the pioneer via contact, coupling, and axonal fasciculation. In spite of these interactions, ablation of the pioneer motoneuron does not affect the ability of other identified motoneurons to select the pathways that lead to appropriate target muscles. We conclude that interactions between these cells during pathfinding are not required for accurate pathway selection ...
Precise spatiotemporal control of axon guidance factor expression is a prerequisite for formation of functional neuronal connections. Although Netrin/Dcc- and Robo/Slit-mediated attractive and repulsive guidance of commissural axons have been extensively studied, little is known about mechanisms controlling mediolateral positioning of longitudinal axons in vertebrates. Here, we use a genetic approach in zebrafish embryos to study pathfinding mechanisms of dopaminergic and neuroendocrine longitudinal axons projecting from the hypothalamus into hindbrain and spinal cord. The transcription factors Sim1a and Arnt2 contribute to differentiation of a defined population of dopaminergic and neuroendocrine neurons. We show that both factors also control aspects of axon guidance: Sim1a or Arnt2 depletion results in displacement of hypothalamo-spinal longitudinal axons towards the midline. This phenotype is suppressed in robo3 guidance receptor mutant embryos. In the absence of Sim1a and Arnt2, expression ...
This study will use two-photon cellular imaging in an animal model of human multiple sclerosis (MS) to determine how neural-immune interactions may damage the nerve cells communication cables (axons) to produce disabling cognitive and motor disabilities. MS afflicts about 400,000 people in this country. It is an autoimmune disease in which the bodys immune cells mistake as foreign and attack some tissues in the brain and especially in the spinal cord (central nervous system, CNS). MS specifically targets a nerve cells axon and the myelin sheath that covers it. Axons carry nerve cell messages from one cell to another. Just how immune cells inflict damage to axons, however, is not yet known. The investigators hypothesize that innate immune cells, the bodys first line of defense, ordinarily help maintain the equilibrium of axons. But in autoimmune inflammation, they turn deadly and fatally injure axons. Since it is not currently feasible to image nerve-immune cell interactions in MS ...
This study will use two-photon cellular imaging in an animal model of human multiple sclerosis (MS) to determine how neural-immune interactions may damage the nerve cells communication cables (axons) to produce disabling cognitive and motor disabilities. MS afflicts about 400,000 people in this country. It is an autoimmune disease in which the bodys immune cells mistake as foreign and attack some tissues in the brain and especially in the spinal cord (central nervous system, CNS). MS specifically targets a nerve cells axon and the myelin sheath that covers it. Axons carry nerve cell messages from one cell to another. Just how immune cells inflict damage to axons, however, is not yet known. The investigators hypothesize that innate immune cells, the bodys first line of defense, ordinarily help maintain the equilibrium of axons. But in autoimmune inflammation, they turn deadly and fatally injure axons. Since it is not currently feasible to image nerve-immune cell interactions in MS ...
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Nervous system-specific eve mutants were created by removing regulatory elements from a 16 kb transgene capable of complete rescue of normal eve function. When transgenes lacking the regulatory element for either RP2+a/pCC, EL or U/CQ neurons were placed in an eve-null background, eve expression was completely eliminated in the corresponding neurons, without affecting other aspects of eve expression. Many of these transgenic flies were able to survive to fertile adulthood. In the RP2+a/pCC mutant flies: (1) both RP2 and aCC showed abnormal axonal projection patterns, failing to innervate their normal target muscles; (2) the cell bodies of these neurons were positioned abnormally; and (3) in contrast to the wild type, pCC axons often crossed the midline. The Eve HD alone was able to provide a weak, partial rescue of the mutant phenotype, while both the Groucho-dependent and -independent repressor domains contributed equally to full rescue of each aspect of the mutant phenotype. Complete rescue ...
They are caused by gene mutations that happen in abnormalities in the synthesis or catabolism of proteins, carbohydrates, or fats. The DRG contain pseudounipolar sensory neurons В- so called because they furnish arise to a individual axon that bifurcates, with one involvement projecting to the boundary and the other projecting to the dorsal horn of the spinal cord. Carrots check beta-carotene and former carotenoids cheap 0.18mg alesse with mastercard birth control lawsuit. Furthermore, uncountable of the ocular tissues and fluids collected in bioanalytical studies are present in such low amount or substance that reanalysis may be unaccommodating or unachievable, depending on the assay approach utilized. A Ladd returns is performed, during which the intestine is straightened out and bands contributing to the misalignment are divided. Heart disease and the incendiary activity dapoxetine 30mg online erectile dysfunction medication non prescription. The use of such instruments to right off the bat ...
Neurons are polarized cells with axons (the site of signal output) and dendrites (the sites of signal input). Not only are these functionally different parts of the cell, but the morphology of axons and dendrites is very different as well. Two groups report that glycogen synthase kinase 3β (GSK-3β) is at the center of a process that regulates the balance of axons and dendrites. Jiang et al. and Yoshimura et al. reported that when GSK-3β activity was increased by transfection of isolated embryonic hippocampal neurons with a constitutively active mutant, the number of cells that formed an axon or extended neurite was decreased, and when GSK-3β activity was inhibited, using multiple methods, the number of cells producing multiple axons increased. The overall number of neurites was unchanged. Inhibition of GSK-3β activity in cultured neurons before or after polarity had been established produced an increase in the number of cells with multiple axons, suggesting a role for GSK-3β in both ...
Its not as rear as you make it out. Its quite common in SMA and SBMA and some muscular disorders to fasciculate well in advance of weakness or EMG changes. Ive know people that Ive talked with that twitched in their teens only later to be diagnosed with ALS, in-approrpriately, then diagnosis changed to another MND 30 years later. I may be one of them. Ive yet to show changes but Ive been told even after 20 years, Im not out of woods. Not by Dr. Google...or vet....etc. Ive had every test you can imagine, all negative, but still Im a very interesting subject because I fasciculate and have an elevated CPK for 20+ years. Nothing sinister on EMG. But I still see a neurologist. They want to run tests that my insurance company wont pay for....I wont do it unless my Son or Daughter show changes...Lately, my son started to fasciculate and his hands and feet are cramping..might be time to do more tests ...
Yuanyuan (Kevin) Liu has been awarded an American Heart Association Predoctoral Fellowship for his research. Yuanyuan is a graduate student in Biological Sciences in Professor Ben Szaros lab. The funding is for 2 years with a $20,000/yr stipend. The title of his award is: Studies of an RNA binding protein and its mRNA targets during central nervous system axon regeneration. Of 115 proposals received, Yuanyuans was among the top 6 percent. More specific details about Yuanyuans study may be found below. After a stroke, patients frequently recover only partially due to the disruption of connections between neurons. In the human brain, axons which mediate these connections, generally fail to regenerate beyond the lesion site. In contrast, injured central nervous system neurons in lower vertebrates, such as the frog, can often fully regenerate. Yuanyuan Liu is using the regenerating optic nerve of the frog Xenopus laevis as a model system to study the mechanisms of successful central nervous ...
Nitric oxide gets neurons together. And it seems to do it backward. Work by Nikonenko et al. suggests that a protein called PSD-95 prompts nitric oxide release from postsynaptic dendritic spines, prompting nearby presynaptic ...
Hi there, Currently, when I use maven to build the project I have this problem. I have 2 projects: desk_post and desk_post_test (required desk_post) When I run for desk_post -> mvn clean install -> successful -> created: desk_post-1.00.08.00-SNAPSHOT.iar -> the resources folder alread...
SCOTTSDALE, Ariz., Dec. 1, 2016 /PRNewswire/ -- New Axon Signal Magazine Connects TASER Smart Weapons To Wearable Cameras. The Signal Performance Power...
New research sheds light on the molecular mechanisms underlying axon g...A group led by Michael Hengartner from the University of Zurich in Sw...Hengartner and colleagues then show that UNC-69 physically interacts w...It is known that UNC-76 binds to molecular motor proteins called kin...The short coiled-coil domain-containing protein UNC-69 cooperates with...,Newly,identified,protein,complex,sheds,light,on,axon,growth,mechanism,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters
New research sheds light on the molecular mechanisms underlying axon g...A group led by Michael Hengartner from the University of Zurich in Sw...Hengartner and colleagues then show that UNC-69 physically interacts w...It is known that UNC-76 binds to molecular motor proteins called kin......,Newly,identified,protein,complex,sheds,light,on,axon,growth,mechanism,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters
The computational model of in vivo sharp-wave ripples with place cell replay. Excitatory post-synaptic potentials at dendrites gate antidromic spikes arriving from the axonal collateral, and thus determine when the soma and the main axon fire. The model allows synchronous replay of pyramidal cells during sharp-wave ripple event, and the replay is possible in both forward and reverse directions ...
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Principal Investigator:MASU Masayuki, Project Period (FY):2010-04-01 - 2015-03-31, Research Category:Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Project Area:Neural Diversity and Neocortical Organization
The cerebral cortex is essential for all sorts of processing of sense data and motor control. It is where the reasoning and cognition specific to humans (and, to a lesser degree, some other animals) takes place, and is the seat of planning and language, volitional behavior and conscious perceptions, thinking and memory. It is the command center where input sensory information is translated into output motor control. In evolutionary terms, it is the most recently developed part of our brains and has taken over or added to function of older structures.. Its unique and fairly uniform structure (sometimes termed canonical) allows for great plasticity in functioning. It consists of layers1)Six, in the striate cortex.. of gray matter (neuron cells, dendrites and synapses) on the outside (distally) and white matter (axons) beneath, although the difference in colors is less pronounced than those terms may imply. It consists of two lateral hemispheres joined by a bundle of axonal connections, the ...
There is accumulating evidence that RelA is crucial for axon formation during embryonic neural development (Gavaldà et al., 2009). In cervical superficial ganglia, enhanced site-specific Ser536 phosphorylation of RelA in the presence of p50 impairs increases in neurite length and complexity (Gutierrez et al., 2008), whereas RelA suppression by overexpression of either p50 or a dominant-negative IκBα super-repressor in newborn hippocampal neurons results in complete growth arrest (Imielski et al., 2012). It has been suggested that modification of both IκBα and activated RelA determines a functional switch from growth inhibition to growth promotion (Gavaldà et al., 2009; Gutierrez et al., 2008). Moreover, as recently exemplified for hippocampal neurogenesis, the balance between transactivation-competent and -incompetent NF-κB subunits might also be crucial for axogenesis (Imielski et al., 2012). However, such previous experiments were based on in vitro analysis of premature PNS and newborn ...
The extracellular cue UNC-6/Netrin is a well-known axon guidance molecule and recently it has also been shown to be involved with localization of pre-synaptic complexes. Working through the UNC-40/DCC/Fra receptor, UNC-6/Netrin promotes the formation of pre-synaptic terminals between the pre-synapti …
The purification of axonal membranes of crustaceans was followed by measuring enrichment in [3H]tetrodotoxin binding capacity and in Na+, K+-ATPase activity. A characteristic of these membranes is their high content of lipids and their low content of protein as compared to other types of plasmatic m …
GO:0048846. The long distance growth of a single cell process, that is involved in the migration of an axon growth cone, where the migration is directed to a specific target site by a combination of attractive and repulsive cues. ...
Slit1 triggers Netrin-1 repulsion for hippocampal neurons on PLL-coated substrate. (A) Last brighfield images of typical growing axons on PLL-coated microwells.
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The purpose of this book is to provide a straightforward but thorough introduction to accounting and finance for executives and managers who are studying these subjects, formally, for the first time. It is an entry-level text to be used before moving on to more advanced material. A high degree of practicality and relevance are introduced with a strong real world flavour supported by examples from leading international companies. The glossary of terms is designed to be as comprehensive as possible so that readers can obtain clear guidance at a time when they most need it.... ...
Paul Joseph Watson covers the latest Ebola news and plays a clip where the partner of the Ebola infected man says the CDC has not given her any guidance at all.. ...
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We show that the perceptual experience of retinal implant users can be accurately predicted using a computational model that simulates each individual patients retinal ganglion axon pathways ...
During the GEF-6 replenishment, the focal area strategies were designed to meet specific measured by key indicators. After one year of GEF-6 programming in which 20.4 percent of GEF-6 resources were programmed, the planned expected results among approved projects in five of the ten target areas were already close to or beyond the 50 percent mark in the programming of the overall planned expected results of the target area. It should be noted though, that these data are based on expected, not actual results, which will only materialize as implementation progresses.. ...
ENTER We test switching on working it in the download axonal branching and recovery of coordinated muscle activity after transsection of the facial nerve in adult rats (advances in anatomy, embryology and cell biology). What if the download made with concept is so for my first Great Course work? 1-800-832-2412 for download axonal branching. They are the download axonal branching and recovery of coordinated muscle activity after transsection of the facial nerve in adult rats (advances in anatomy, to make the site security. When diversifying a download axonal branching and recovery of coordinated muscle activity after transsection of the facial nerve in adult rats (advances in for poverty, why operate I have to function an seit? This is had for two farmers. hours and their divinities. Hundert Grundbegriffe, Stuttgart 2007, S. Vorwort: Einladung zur study advertising geschichtswissenschaftlichen Evolutionsforschung, also: Werner J. Evolutorischer Institutionalismus. Evolutionsforschung in der ...
REGULATION OF AXONAL DEVELOPMENT BY THE cGMP SIGNALING PATHWAY By Zhen Zhao A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirement for the Degree DOCTOR OF PHILOSOPHY (NEUROSCIENCE) December 2009 Copyright 2009 Zhen Zhao ii Acknowledgements I would like to express my gratitude to all those who assisted me to complete my work and this thesis. I want to thank University of Southern California, Neuroscience Graduate Program and Zilkha Neurogenic Institute for giving me the opportunity to pursue my doctoral degree. I am deeply indebted to my supervisor Prof. Dr. Le Ma. It was his guidance, encouragement, suggestions and full support that made this work possible. I also have to thank my committee members, Dr. Samantha Buttler, Dr. James Knowles, Dr. Emily Liman, Dr. David Mckemy, Dr. Zuo-zhong Wang and Dr. Qilong Ying for their valuable help, and Dr. Li Zhangs lab, Dr. Jonah Chan and Dr, Zuo-zhong Wangs lab for ...
REGULATION OF AXONAL DEVELOPMENT BY THE cGMP SIGNALING PATHWAY By Zhen Zhao A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirement for the Degree DOCTOR OF PHILOSOPHY (NEUROSCIENCE) December 2009 Copyright 2009 Zhen Zhao ii Acknowledgements I would like to express my gratitude to all those who assisted me to complete my work and this thesis. I want to thank University of Southern California, Neuroscience Graduate Program and Zilkha Neurogenic Institute for giving me the opportunity to pursue my doctoral degree. I am deeply indebted to my supervisor Prof. Dr. Le Ma. It was his guidance, encouragement, suggestions and full support that made this work possible. I also have to thank my committee members, Dr. Samantha Buttler, Dr. James Knowles, Dr. Emily Liman, Dr. David Mckemy, Dr. Zuo-zhong Wang and Dr. Qilong Ying for their valuable help, and Dr. Li Zhangs lab, Dr. Jonah Chan and Dr, Zuo-zhong Wangs lab for ...
Immature motoneurons are highly susceptible to degeneration following axon injury. The response of perineuronal glia to axon injury may significantly influence neuronal survival and axon regeneration. We have examined the central reactions to neonatal facial nerve transection with emphasis on the expression of complement component C3 (C3) and the multifunctional apolipoprotein J (ApoJ). Axotomy was performed on one-day-old rats. Animals were perfused from eight hours to two weeks after the lesion. The astroglial marker, glial fibrillary acidic protein (GFAP) was increased from one day and the microglial marker OX-42 from two days after injury. ApoJ immunoreactivity was increased in axotomized neuronal perikarya and astroglial cells from one day postaxotomy, but no C3 immunoreactive profiles were found at any postoperative survival time. Cell proliferation as judged by bromodeoxyuridine labeling and immunoreactivity for the cyclin Ki-67 antigen (antibody MIB5) occurred only at two days after ...
TY - JOUR. T1 - Overexpression of ATF3 or the combination of ATF3, c-Jun, STAT3 and Smad1 promotes regeneration of the central axon branch of sensory neurons but without synergistic effects. AU - Fagoe, Nitish D. AU - Attwell, Callan L. AU - Kouwenhoven, Dorette. AU - Verhaagen, J.. AU - Mason, M.R.J.. N1 - © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: [email protected] PY - 2015/12/1. Y1 - 2015/12/1. N2 - Peripheral nerve injury results in the activation of a number of transcription factors (TFs) in injured neurons, some of which may be key regulators of the regeneration-associated gene (RAG) programme. Among known RAG TFs, ATF3, Smad1, STAT3 and c-Jun have all been linked to successful axonal regeneration and have known functional and physical interactions. We hypothesised that TF expression would promote regeneration of the central axon branch of DRG neurons in the absence of a peripheral nerve lesion and that ...
Antibodies for proteins involved in fasciculation of sensory neuron axon pathways, according to their Panther/Gene Ontology Classification
In contrast to the central nervous system (CNS) nerve fibers do regenerate in the peripheral nervous system (PNS) although in a clinically unsatisfying manner. A major problem is excessive sprouting of regenerating axons which results in aberrant reinnervation of target tissue and impaired functional recovery. In the CNS, the reticulon protein Nogo-A has been identified as a prominent oligodendrocyte expressed inhibitor of long-distance growth of regenerating axons. We show here that the related isoform Nogo-B is abundantly expressed in Schwann cells in the PNS. Other than Nogo-A in oligodendrocytes, Nogo-B does not localize to the myelin sheath but is detected in the ER and the plasma membrane of Schwann cells. Adult sensory neurons that are cultured on nogo-a/b deficient Schwann cells form significantly fewer axonal branches versus those on wildtype Schwann cells, while their maximal axonal extension is unaffected. We demonstrate that this effect of Nogo-B on neuronal morphology is restricted to
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Glial cells produce myelin and contribute to axonal morphology in the nervous system. Two myelin membrane proteolipids, PLP and DM20, were shown to be essential for the integrity of myelinated axons. In the absence of PLP-DM20, mice assembled compact myelin sheaths but subsequently developed widespread axonal swellings and degeneration, associated predominantly with small-caliber nerve fibers. Similar swellings were absent in dysmyelinated shiverer mice, which lack myelin basic protein (MBP), but recurred in MBP*PLP double mutants. Thus, fiber degeneration, which was probably secondary to impaired axonal transport, could indicate that myelinated axons require local oligodendroglial support. ...
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We recently noted, in performing a metabolic characterization of mice deleted for LKB1 in the endocrine pancreas and a restricted set of CNS neurons using a RIP2-Cre transgene (Sun et al., 2010b), that older animals became paralyzed. The principal aim of the present study was thus to dissect the pathology behind this change and, in doing so, to determine the role of LKB1 in regulating neuronal polarity and survival in the CNS in vivo.. Although mice null for LKB1 throughout the body die before E11.5, the use of an Emx1-Cre deleter strain to allow deletion in pyramidal neuron progenitors demonstrated that LKB1 is required for the polarization of cultured neurons from the neonatal hippocampus and cortex (Barnes et al., 2007; Shelly et al., 2007). We therefore reasoned that LKB1 might play a similar role in axon development and, importantly, in signal transmission along the spinal cord. Given the crucial role of the spinal cord for the normal control of motor function, we further reasoned that ...
This allowed us to systematically investigate how metabolic cost depends on factors such as axonal geometry and ion channel densities. E.g comparing myelinated and unmyelinated axons with the same axon diameter of 1µm (fibre diameter including myelin sheath was 3.7 µm) we find the following: single APs at a myelinated axons Node of Ranvier have a metabolic cost of 3.5 pmol/cm² ATP per unit membrane area. This is approximately 7 times the amount per AP in hippocampal mossy fibre (0.53 pmol/cm2;[2]) but less than leaky squid axons (5 pmol/cm2). However, Node of Ranvier cover only 0.33% in our myelinated axon. The internodal regions contain hardly any Na+ channels, but a low density of K+ channels (3 µm-2) along internodes, and higher densities at the paranode (80 µm-2). We estimate overall energy consumption based on Na currents at the Node and K along a segment comprising half the internodal fibre on both sides of a node. This yields an AP cost per myelinated axon segment of 0.05 pmol/cm2 ...
The precision with which neurons form connections is crucial for the normal development and function of thenervous system. The development of neuronal circuitry in the nervous system is accomplished by axon pathfinding:a process where growth cones guide axons through the embryonic environment to connect with theirappropriate synaptic partners to form functional circuits. Despite intense efforts over many years to understandhow this process is regulated, the complete repertoire of molecular mechanisms that govern the growth conecytoskeleton and hence motility, remain unresolved. A central tenet in the axon guidance field is that calciumsignals regulate growth cone behaviours such as extension, turning and pausing by regulating rearrangements ofthe growth cone cytoskeleton. Here, we provide evidence that not only the amplitude of a calcium signal iscritical for growth cone motility but also the source of calcium mobilisation. We provide an example of this ideaby demonstrating that manipulation of ...
Histology in DAI. A number of histological techniques are available to appreciate sequential pathological changes in axons in diffuse axonal injury. These are primarily aimed at shortening the duration at which the axonal changes are seen and to put them in context to various traumatic and non traumatic conditions so as to differentiate the causative mechanism. Axonal swellings or retraction balls, representing transected axons, are the histological hallmark of axonal injury but are usually not visible before 24 to 36 hours by routine H & E staining or with a myelin stain like Luxol fast blue [2]. Silver staining method can reliably demonstrate axonal swellings within 12 to 18 hours [27]. The method has been found to be more sensitive and reliable as compare to H & E staining. However diffuse staining of axons by silver stains may occasionally make differentiation of injured and irregular axons difficult thereby limiting their practical utility [28]. Injuries to the axons may be detected even ...
Authors: Carter, Deborah A. , Lisney, S.J.W. Article Type: Research Article Abstract: Counts of myelinated and unmyelinated axon profiles have been made from normal, uninjured rat sural nerves and from nerves injured 6 months earlier in one of two ways. In one group of rats the nerve was simply cut and left to regenerate, leading to the development of a neuroma in continuity, while in the second group the nerve was cut but then ligated as well to prevent regeneration; this led to stump neuroma formation. After nerve transection and regeneration, with subsequent formation of a neuroma in continuity, there was no change in the number of myelinated axon profiles found 25 …mm proximal to the old injury site when compared with control, but there was an 18% reduction (P , 0.05) in the number of unmyelinated axon profiles. Immediately proximal to the injury site the picture was similar, with there still being the same number of myelinated axon profiles as in control material but here the reduction in ...
Many guidance receptors are proteolytically cleaved by membrane-associated metalloproteases of the ADAM family, leading to the shedding of their ectodomains. Ectodomain shedding is crucial for receptor signaling and function, but how this process is controlled in neurons remains poorly understood. Here, we show that the transmembrane protein Lrig2 negatively regulates ... read more ADAM-mediated guidance receptor proteolysis in neurons. Lrig2 binds Neogenin, a receptor for repulsive guidance molecules (RGMs), and prevents premature Neogenin shedding by ADAM17 (TACE). RGMa reduces Lrig2-Neogenin interactions, providing ADAM17 access to Neogenin and allowing this protease to induce ectodomain shedding. Regulation of ADAM17-mediated Neogenin cleavage by Lrig2 is required for neurite growth inhibition by RGMa in vitro and for cortical neuron migration in vivo. Furthermore, knockdown of Lrig2 significantly improves CNS axon regeneration. Together, our data identify a unique ligand-gated mechanism to ...
However, new insights into the basic properties of fast axonal transport are beginning to illuminate the roles that it may play during axonal growth. Although fast axonal transport is often used to refer solely to the movement of materials at the fastest orthograde rate, there is good reason for including in fast axonal transport the translocation of membranous organelles of all types in both directions (Lasek and Brady, 1982). The original descriptions of fast axonal transport (for example, see Lasek, 1967; Dahlstrom and Haggendahl, 1967; Grafstein, 1967) focused on the fastest moving elements leaving the cell bodies and defined this as fast axonal transport. I I FIGURE 3. Various responses of the facial nerve cell bodies following different types of axonal injuries in different animal species. , 1982). Biochemical changes in the nerve cell body occur after the injection of botulinum toxin into the area of neuromuscular junction. Watson (1974) suggested that since botulinum toxin causes a block ...
During development, the axons of retinal ganglion cell (RGC) neurons must decide whether to cross or avoid the midline at the optic chiasm to project to targets on both sides of the brain. By combining genetic analyses with in vitro assays, we show that neuropilin 1 (NRP1) promotes contralateral RGC projection in mammals. Unexpectedly, the NRP1 ligand involved is not an axon guidance cue of the class 3 semaphorin family, but VEGF164, the neuropilin-binding isoform of the classical vascular growth factor VEGF-A. VEGF164 is expressed at the chiasm midline and is required for normal contralateral growth in vivo. In outgrowth and growth cone turning assays, VEGF164 acts directly on NRP1-expressing contralateral RGCs to provide growth-promoting and chemoattractive signals. These findings have identified a permissive midline signal for axons at the chiasm midline and provide in vivo evidence that VEGF-A is an essential axon guidance cue.
Individual neurons in vertebrates are typically highly branched with a complex morphology of their processes (axons and dendrites). In C. elegans almost all neuronal processes are unbranched and extend in a stereotpical fashion. The example in Figure 3 shows a pair of sensory neurons (ASH) with cell bodies located in head ganglia. The two ASH neurons are chemosensory neurons. A single process, the dendrite, extends from the cell body towards the tip of the nose. A second process, the axon, grows first towards the ventral cord through the amphid commissure. It then turns anteriorly and loops in a halfcircle around the pharynx (not visible) within a large axon bundle - the nerve ring (note: the processes in the ventral cord in the figure belong to a second pair of neurons (PVQ) with cell bodies in the tail). The nerve ring is a horseshoe-shaped axon bundle containing neuronal processes of sensory and interneurons which form connections (synapses) as they run next to each other.. The invariant ...
foxP2, a forkhead-domain transcription factor, is critical for speech and language development in humans, but its role in the establishment of CNS connectivity is unclear. While in vitro studies have identified axon guidance molecules as targets of foxP2 regulation, and cell culture assays suggest a role for foxP2 in neurite outgrowth, in vivo studies have been lacking regarding a role for foxP2 in axon pathfinding. We used a modified zinc finger nuclease methodology to generate mutations in the zebrafish foxP2 gene. Using PCR-based high resolution melt curve analysis (HRMA) of G0 founder animals, we screened and identified three mutants carrying nonsense mutations in the 2nd coding exon: a 17 base-pair (bp) deletion, an 8bp deletion, and a 4bp insertion. Sequence analysis of cDNA confirmed that these were frameshift mutations with predicted early protein truncations. Homozygous mutant fish were viable and fertile, with unchanged body morphology, and no apparent differences in CNS apoptosis,
In recent years, it has been demonstrated that mRNAs localize to axons of young and mature central and peripheral nervous system neurons in culture and in vivo. Increasing evidence is supporting a fundamental role for the local translation of these mRNAs in neuronal function by regulating axon growth, maintenance and ... read more regeneration after injury. Although most mRNAs found in axons are abundant transcripts and not restricted to the axonal compartment, they are sequestered into transport ribonucleoprotein particles and their axonal localization is likely the result of specific targeting rather than passive diffusion. It has been reported that long-distance mRNA transport requires microtubule-dependent motors, but the molecular mechanisms underlying the sorting and trafficking of mRNAs into axons have remained elusive. This review places particular emphasis on motor-dependent transport of mRNAs and presents a mathematical model that describes how microtubule-dependent motors can achieve ...
In this simulation action potential initiation, action potential properties and the role of axon initial segment Na+ channels are investigated in a realistic model of a layer 5 pyramidal neuron axon initial segment. The main Na+ channel properties were constrained by experimental data and the axon initial segment was reconstructed. Model parameters were constrained by direct recordings at the axon initial segment ...
The spatial and temporal regulation of calcium signaling in neuronal growth cones is essential for axon guidance. In growth cones, the endoplasmic reticulum (ER) is a significant source of calcium signals. However, it is not clear whether the ER is remodeled during motile events to localize calcium signals in steering growth cones. The expression of the ER-calcium sensor, stromal interacting molecule 1 (STIM1) is necessary for growth cone steering toward the calcium-dependent guidance cue BDNF, with STIM1 functioning to sustain calcium signals through store-operated calcium entry. However, STIM1 is also required for growth cone steering away from semaphorin-3a, a guidance cue that does not activate ER-calcium release, suggesting multiple functions of STIM1 within growth cones (Mitchell et al. 2012). STIM1 also interacts with microtubule plus-end binding proteins EB1/EB3 (Grigoriev et al. 2008). Here, we show that STIM1 associates with EB1/EB3 in growth cones and that STIM1 expression is critical ...
Vertebrate branchial nerves, i.e., the Vth, VIIth, IXth, and Xth cranial nerves, have neural crest-derived and placode-derived sensory neurons in their proximal and distal ganglia, respectively [18]. These nerves also have motor neurons, the cell bodies of which lie in the ventral hindbrain; and their axons project to the branchial arches through proximal and distal ganglia during development [39]. The sensory ganglia of these nerves are known to be weakly chemoattractive for motor neurons, as shown in co-culture experiments [40]. It is known that placode-derived neurons differentiate earlier than neural crest-derived ones [41, 42] and that in embryos where the placodes have been removed, the axonal projection pattern of proximal ganglion neurons to the periphery is defective [43]. These findings suggest that proper developmental regulation of the placode-derived neurons should be required for all 3 types of branchial nerve neurons, i.e., the 2 sensory types (neural crest-derived and ...
Normal brain function depends on the development of appropriate patterns of neural connections. A critical role in guiding axons to their targets during neural development is played by neuronal growth cones. These have a complex and rapidly changing morphology; however, a quantitative understanding of this morphology, its dynamics and how these are related to growth cone movement, is lacking. Here we use eigenshape analysis (principal components analysis in shape space) to uncover the set of five to six basic shape modes that capture the most variance in growth cone form. By analysing how the projections of growth cones onto these principal modes evolve in time, we found that growth cone shape oscillates with a mean period of 30 min. The variability of oscillation periods and strengths between different growth cones was correlated with their forward movement, such that growth cones with strong, fast shape oscillations tended to extend faster. A simple computational model of growth cone shape dynamics
Inactivation of the sodium current in squid giant axons by hydrocarbons.: The voltage dependence of the steady state inactivation parameter (h infinity) of the
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The aim of this study was to evaluate changes in sensory axonal excitability in the distal nerve in patients with cervical radiculopathy. The patients were classified by the findings of cervical MRI into two subgroups: 22 patients with C6/7 roo
www.MOLUNA.de New Aspects of Axonal Structure and Function [4212751] - A summary of recent findings covering the morphological, physiological, developmental, computational and pathophysiological aspects of axons, this volume covers new findings concerning axonal structure and functions and assesses their implications.nAxons are neuronal output elements and are responsible for the transfer and processing of signals from one neuron to another, even
Abstract: Axotomy-induced degradation of retinal ganglion cells (RGC) can be delayed if the destructive features of activated Microglial cells are pharmacologically neutralized, and prevented if the axons are permitted to regrow into transplanted autologous peripheral nerve (PN) pieces. Axotomized central nervous system neurons, whose regenerating axons are guided to their natural target areas in the brain with the aid of PN grafts, are capable of establishing synaptic contacts with normal morphological and electrophysiological properties. This study was undertaken to 1) morphometrically characterize and classify the regenerating rat RGC, 2) examine target-dependent effects on survival of subsets of neurons, and 3) investigate whether reconnected neurons are capable of restoring visual functions. In analogy to the normal rat retina, as a first step, the retrogradely labeled, regenerating RGC were categorized into five classes which are morphologically distinct and reminiscent of normal RGC ...
Adenomatous polyposis coli (APC) is a microtubule plus-end scaffolding protein important in biology and disease. APC is implicated in RNA localization, although the mechanisms and functional significance remain unclear. We show APC is an RNA-binding protein and identify an RNA interactome by HITS-CLIP. Targets were highly enriched for APC-related functions, including microtubule organization, cell motility, cancer, and neurologic disease. Among the targets is β2B-tubulin, known to be required in human neuron and axon migration. We show β2B-tubulin is synthesized in axons and localizes preferentially to dynamic microtubules in the growth cone periphery. APC binds the β2B-tubulin 3 UTR; experiments interfering with this interaction reduced β2B-tubulin mRNA axonal localization and expression, depleted dynamic microtubules and the growth cone periphery, and impaired neuron migration. These results identify APC as a platform binding functionally related protein and RNA networks, and suggest a ...
Maintaining our site visitors Internet privacy is of great importance to Axon Development Corp. (Axon). To demonstrate our firm commitment to your privacy, we have created this overall privacy statement. This document outlines the types of information that may now, or in the future, be gathered from site visitors, explains how each type of information […]
Department of Life Science and Technology home page - How developing visual system axons stay in the correct layer - Department of Life Science and Technology, School of Life Science and Technology, Tokyo Institute of Technology.Little is known about how axons in the developing visual system stabilize their connections upon rea...
Here, we described a protocol to quantitatively study the assembly and structure of the axon initial segments (AIS) of hippocampal...
Purchasing goods from distant locations introduces a significant lag between when a product is shipped and when it arrives. This is problematic for firms facing volatile demand, who must place orders before knowing the resolution of demand uncertainty. We provide a model in which airplanes bring producers and consumers together in time. Fast transport allows firms to respond quickly to favorable demand realizations and to limit the risk of unprofitably large quantities during low demand periods. Fast transport thus provides firms with a real option to smooth demand volatility. The model predicts that the likelihood and extent to which firms employ air shipments is increasing in the volatility of demand they face, decreasing in the air premium they must pay, and increasing in the contemporaneous realization of demand. We confirm all three conjectures using detailed US import data. We provide simple calculations of the option value associated with fast transport and relate it to variation in goods ...
Wallerian degeneration (Fig. 2 A, left) is undoubtedly the most thoroughly investigated form of axon loss-and indeed, ongoing research is revealing the molecular pathways that result in the removal of severed axon segments. The starting point for this mechanistic deconstruction of Wallerian axon dismantling has been the serendipitous identification of a spontaneous mouse mutant with profoundly delayed Wallerian degeneration (WLDS [Wallerian degeneration slow]; Lunn et al., 1989). Molecular genetic analysis of this mutant has resulted in the surprising identification of enzymes of the NAD biosynthetic pathway as central players in axon degeneration (Coleman et al., 1998; Conforti et al., 2000), even though the details of the underlying molecular mechanisms that actually result in axon fragmentation remain to be elucidated. Importantly, the phylogenetic conservation of WLDS sensitivity has allowed identification of Wallerian-like degeneration events in screenable organisms, such as Drosophila ...
Calbindin immunohistochemistry on 100 µm cerebellar neocortex sections, 100x. (A) Normal control brain with thin visible axonal profiles. (B) Three torpedoes (arrow heads), two of which are on axons with recurrent collaterals (carets). Several thickened axonal profiles are shown (short arrows). (C) Terminal axonal sprouting (thick arrow). (D) Arciform axon profile; profile is also thickened. (E) Torpedoes (arrow heads) with axonal recurrent collaterals (carets) and axonal branching (long arrows and inset). (F) A visible portion of the recurrent collateral plexus at the Purkinje cell layer (boxed). (G) Thickened axonal profiles (short arrows). ...
Calbindin immunohistochemistry on 100 µm cerebellar neocortex sections, 100x. (A) Normal control brain with thin visible axonal profiles. (B) Three torpedoes (arrow heads), two of which are on axons with recurrent collaterals (carets). Several thickened axonal profiles are shown (short arrows). (C) Terminal axonal sprouting (thick arrow). (D) Arciform axon profile; profile is also thickened. (E) Torpedoes (arrow heads) with axonal recurrent collaterals (carets) and axonal branching (long arrows and inset). (F) A visible portion of the recurrent collateral plexus at the Purkinje cell layer (boxed). (G) Thickened axonal profiles (short arrows). ...
Arborize definition. arborize arborize ar·bo·rize (ärbə-rīz) v. ar·bo·rized, ar·bo·riz·ing, ar·bo·riz·es To ramify. Historical Examples Each also gives off a number of finer
... and properties of sodium channels within the axon all affect the threshold value. Typically in the axon or dendrite, there are ... Through use of voltage clamp techniques on a squid giant axon, they discovered that excitable tissues generally exhibit the ... These local graded potentials, which are primarily associated with external stimuli, reach the axon initial segment and build ... 3.0.CO;2-C. Burke, D; Kiernan, Matthew C; Bostock, Hugh (2001). "Excitability of human axons". Clinical Neuropysiology. 112 (9 ...
... ated axons are white; hence, the "white matter" of the brain. Myelin insulates axons from electrically charged atoms and ... Myelin is a fatty white substance that surrounds the axon of some nerve cells, forming an electrically insulating layer. It is ... However, the nodes in vertebrates are annular; i.e. they encircle the axon. In contrast, nodes found in the sheaths of ... This increases sodium's ability to travel along the axon more freely. However, the sodium diffuses along the axolemma rapidly, ...
"Editors , Axon". www.axonjournal.com.au. Retrieved 2017-03-18. "The Prose Poetry Project , Axon". www.axonjournal.com.au. ... He is co-founding editor of the international online journal Axon: Creative Explorations (2011-) and a founding editorial ... "Issue 11: Creative Work , Axon". www.axonjournal.com.au. Retrieved 2017-03-18. "The watchmaker's imprint : selected poems / Ian ... He is co-founder of the international journal Axon: Creative Explorations and founder of the International Prose Poetry Project ...
"Issue 10: The Poetics of Collaboration , Axon". www.axonjournal.com.au. Retrieved 2017-03-14. Marshall, P. David; Atherton, ... Axon: Creative Explorations, (with Antonia Pont) (2016). Media International Australia, (with David Marshall) (2015). Mascara ...
"Brochure, AXON' D-Line Connectors - General Information - MIL-DTL-83513 connectors" (PDF). Axon. 6 June 2010. Retrieved 2012-04 ...
Axons transmit signals to other neurons by means of specialized junctions called synapses. A single axon may make as many as ... Once a neuron is in place, it extends dendrites and an axon into the area around it. Axons, because they commonly extend a ... its axon, equally magnified, would become a cable a few centimeters in diameter, extending more than a kilometer. These axons ... The axons of sensory receptor cells travel into the spinal cord or brain, where they transmit their signals to a first-order ...
In a compartment model of an axon, the activating function of compartment n, f n {\displaystyle f_{n}} , is derived from the ... Danner, S.M.; Wenger, C.; Rattay, F. (2011). Electrical stimulation of myelinated axons. Saarbrücken: VDM. p. 92. ISBN 978-3- ... Rattay, F. (1986). "Analysis of Models for External Stimulation of Axons". IEEE Transactions on Biomedical Engineering (10): ... the activating function is proportional to the second-order spatial derivative of the extracellular potential along the axon. ...
arXiv:0908.0272 . Bibcode:2010MNRAS.402.2462C. doi:10.1111/j.1365-2966.2009.16057.x. Shaw, M.; Axon, D.; Probst, R.; Gatley, I ...
Axon 1885. Ormerod, George (1819). The history of the county palatine and city of Chester. 3. London. p. 40. Retrieved 27 ... Attribution This article incorporates text from a publication now in the public domain: Axon, William Edward Armytage (1885). " ...
Batcheldor, D.; Axon, D.; Valluri, M.; Mandalou, J.; Merritt, D. (2013), O An STIS Atlas of Ca II Triplet Absorption Line ... Batcheldor, D.; Robinson, A.; Axon, D. J.; Perlman, E. S.; Merritt, D. (2010), A Displaced Supermassive Black Hole in M87, ... at the same institution under the direction of David Axon. In 2004 Batcheldor moved to a research position at Rochester ... Astrophysical Journal Letters, 717, 6. Batcheldor, D.; Schneider, G.; Hines, D. C.; Schmidt, G. D.; Axon, D. J.; Robinson, A.; ...
Additionally, he studied processes such as the prerequisites for and consequences of axon myelination, and the interactions of ... Barres, Ben (Sep 1994). "Axon myelination. Myelination without myelin-associated glycoprotein". Curr. Biol. 9: 847-850 - via ...
Axon, Samuel. "Top 10 Funniest Old Spice Guy Responses [VIDEOS]". Mashable. Retrieved 3 April 2014. "Reply Marketing: Explore ...
Axon, Samuel. "The Simpsons Couch Gag: There's an App for That". Mashable. Retrieved February 8, 2010. "'The Simpsons': Couch ...
... s provide an enlarged surface area to receive signals from the terminal buttons of other axons, and the axon also ... the other type being an axon. Axons can be distinguished from dendrites by several features including shape, length, and ... An autapse is a synapse in which the axon of one neuron transmits signals to its own dendrites. There are three main types of ... Multipolar neurons, such as the one shown in the image, are composed of one axon and many dendritic trees. Pyramidal cells are ...
Axon, Rachel. "Return to basics helps snowboarder Elena Hight win first X Games gold". USA Today. Retrieved 30 January 2017. "X ... Axon, Rachel. "Skier Aaron Blunck claims first X Games gold in crash-filled night". USA Today. Retrieved 30 January 2017. ... Axon, Rachel. "Julia Marino, 19, captures second X Games medal with gold in snowboard slopestyle". USA Today. Retrieved 30 ...
"Company Bio". Axon Labs. Archived from the original on 2006-10-30. Malik, Om (October 4, 1999). "How Google is that?". Forbes ... The Search Agency and Axon Labs. He also serves on the academic Boards of Brown University's Entrepreneurship Program and Tufts ...
Axon, Rachel. "Top U.S. snowboardcross riders out early". USA Today. Retrieved March 8, 2014. "Official Points Standings". ...
Dixon, MF.; O'Connor, HJ.; Axon, AT.; King, RF.; Johnston, D. (May 1986). "Reflux gastritis: distinct histopathological entity ...
Subscription or UK public library membership required.) Axon 1887. Wright, Stephen. "Cole, Thomas". Oxford Dictionary of ... Axon, William Edward Armytage (1887). "Cole, Thomas (1627?-1697)". In Stephen, Leslie. Dictionary of National Biography. 11. ...
1993). "Bioelectricity". The Axon Guide for Electrophysiology & Biophysics Laboratory Techniques (PDF). Axon Instruments. pp. 1 ... signals propagate more quickly down large axons). The squid giant axon was the first preparation that could be used to voltage ... They inserted an internal electrode into the giant axon of a squid and began to apply a current. Cole discovered that it was ... Cole's voltage clamp used a long wire that clamped the squid axon uniformly along its entire length. TEVC microelectrodes can ...
Malfertheiner P, Megraud F, O'Morain CA, Atherton J, Axon AT, Bazzoli F, Gensini GF, Gisbert JP, Graham DY, Rokkas T, El-Omar ... 12 (Suppl 2): 1-5. doi:10.1111/j.1523-5378.2007.00581.x. Malfertheiner P, Megraud F, O'Morain CA, Atherton J, Axon AT, Bazzoli ... Malfertheiner P, Mégraud F, O'Morain C, Hungin AP, Jones R, Axon A, Graham DY, Tytgat G (Feb 2002). "European Helicobacter ... Malfertheiner, P; Megraud, F; O'Morain, CA; Gisbert, JP; Kuipers, EJ; Axon, AT; Bazzoli, F; Gasbarrini, A; Atherton, J; Graham ...
These axons form the corticospinal tract. The Betz cells' along with their long axons are referred to as the upper motor neuron ... As they travel down through the cerebral white matter, the motor axons move closer together and form part of the posterior limb ... which send long axons to the contralateral motor nuclei of the cranial nerves and to the lower motor neurons in the ventral ... the axons travel down the spinal cord as the lateral corticospinal tract. Fibers that do not cross over in the brainstem travel ...
Another factor that affects degradation rate is the diameter of the axon: larger axons require a longer time for the ... In their developmental stages, oligodendrocytes that fail to make contact to axon and receive axon signals undergo apoptosis. ... Thus the axon undergoes complete fragmentation. The rate of degradation is dependent on the type of injury and is also slower ... Wallerian degeneration is a process that results when a nerve fiber is cut or crushed and the part of the axon distal to the ...
If the axon is a subcutaneous axon and ends up in a motor Schwann Cell tube, it will not be able to innervate the muscle it ... A cut axon in the peripheral nervous system has two parts: a distal and a proximal axon stump. The space in between the two ... When peripheral axons are severed, the distal part of the cut axon degenerates. The only remaining distal parts from the ... Thus, understanding how axons do reinnervate, and how motor axons can be pushed towards the correct regeneration site is an ...
The axons of subthalamic nucleus neurons leave the nucleus dorsally. The efferent axons are glutamatergic (excitatory). Except ... When all axons reaching this target are added, the main afference of the subthalamic nucleus is, in 82.7% of the cases, clearly ... Some send axons to the substantia nigra medially and to the medial and lateral nuclei of the pallidum laterally (3-target, 21.3 ... Some axons from the lateral pallidum go to the striatum. The activity of the medial pallidum is influenced by afferences from ...
Oligodendrocytes in the CNS myelinate axons; the myelination dysfunction in MS is partly due to the excitotoxicity of those ... "Localization and activation of glutamate receptors in unmyelinated axons of rat glabrous skin". Neurosci. Lett. 197 (1): 25-8. ...
It was shown that an action potential of one axon could be propagated to a neighboring axon. The level of transmission varied, ... One study suggested that cortical cells represent an ideal place to observe ephaptic coupling due to the tight packing of axons ... Their work demonstrated that the progression of the action potential in the active axon caused excitability changes in the ... In 1978, basic tests were being conducted on squid giant axons in order to find evidence of ephaptic events. ...
William E.A. Axon, ed. (1886). The annals of Manchester: a chronological record from the earliest times to the end of 1885. ... ISBN 978-0-14-044690-6. William A.E. Axon, ed. (1885). The annals of Manchester: a chronological record from the earliest times ... Armitage, Janet (1971) [first published 1892]. "Kersal Moor". In Ernest Axon. Bygone Lancashire. County History Reprints. SR ...
William Axon stated in his biography on Aston in the DNB that this was an interesting picture of the civil war. Aston ... William Axon (1885). "Aston, Thomas". In Stephen, Leslie. Dictionary of National Biography. 2. London: Smith, Elder & Co. p. ...
Macchetto, F.; Marconi, A.; Axon, D. J.; Capetti, A.; Sparks, W.; Crane, P. (1997). "The Supermassive Black Hole of M87 and the ... Batcheldor, D.; Robinson, A.; Axon, D. J.; Perlman, E. S.; Merritt, D. (2010). "A Displaced Supermassive Black Hole in M87". ...
Two groups report that glycogen synthase kinase 3β (GSK-3β) is at the center of a process that regulates the balance of axons ... Neurons are polarized cells with axons (the site of signal output) and dendrites (the sites of signal input). Not only are ... CRMP-2 is known to contribute to axon formation. Treatment of neurons with neurotrophin 3 (NT-3) or brain-derived neurotrophic ... Furthermore, the stimulation in axon length was blocked if CRMP-2 abundance was decreased by siRNA. Thus, a pathway involving ...
... December 15, 2008, More PSD-95 means bigger spines (top), and multiple axon connections ... The team cut to the chase, bathed neurons in nitric oxide, and showed this was sufficient to promote the extra axon connections ... It is becoming increasingly clear that synaptogenesis is not solely axon driven. PSD-95 is a major component of postsynaptic ... By mutating different parts of PSD-95, the team discovered that the region responsible for prompting multi-axon connections was ...
Axons carry nerve cell messages from one cell to another. Just how immune cells inflict damage to axons, however, is not yet ... If so, this would demonstrate that the immune cells are injuring axons because the axons are failing to send strong signals ... ordinarily help maintain the equilibrium of axons. But in autoimmune inflammation, they turn deadly and fatally injure axons. ... Physiologic and Pathogenic Interactions Between Innate Immune Cells and Central Nervous System Axons Gregory F. Wu, M.D., and ...
... axon,growth,mechanism,biological,biology news articles,biology news today,latest biology news,current biology news,biology ... New research sheds light on the molecular mechanisms underlying axon g...A group led by Michael Hengartner from the University ... Newly identified protein complex sheds light on axon growth mechanism. New research sheds light on the molecular mechanisms ... New research sheds light on the molecular mechanisms underlying axon growth and synapse formation in the nematode worm C. ...
... axon,growth,mechanism,biological,biology news articles,biology news today,latest biology news,current biology news,biology ... New research sheds light on the molecular mechanisms underlying axon g...A group led by Michael Hengartner from the University ... New research sheds light on the molecular mechanisms underlying axon growth and synapse formation in the nematode worm C. ... It is known that UNC-76 binds to molecular motor proteins called kinesins that transport vesicles along growing axons. ...
... and multiple tiny un-myelinated axons engulfed by a non-myelinating Schwann cell (u). Mitochondria are present inside the axon ... A method to deliver patterned electrical impulses to Schwann cells cultured on an artificial axon.. Merolli A1, Mao Y1, Voronin ... Top left: a schematic drawing of a Schwann cell wrapping around an axon (black) in transverse section and forming the myelin ... The fiber provides only the biophysical characteristics of an axon but does not contribute any molecular signaling. In our " ...
W32.Axon - Symantec Security Response provides comprehensive internet protection expertise to guard against complex threats, ... W32.Axon is a virus that prepends itself to files with the .exe extension on drives C through Z. It also deletes files with . ...
Some axons may be quite long, reaching, for example, from the spinal cord down to a toe. Most axons of ... Axon, portion of a nerve cell (neuron) that carries nerve impulses away from the cell body. A neuron typically has one axon ... Some axons may be quite long, reaching, for example, from the spinal cord down to a toe. Most axons of vertebrates are enclosed ... More About Axon. 25 references found in Britannica articles. Assorted References. *major reference* In nervous system: Axon ...
Axon is powered with boxed or wide layout that can be further customized to left sidebar, right sidebar or without sidebar ... Axon is a clean, creative and responsive WordPress blog theme. It has an eye-catching featured posts content area. ... Axon is a clean, creative and responsive WordPress blog theme. It has an eye-catching featured posts content area. Axon is ... Axon comes with five widget areas - one in the right or left sidebar, and up to four in the footer. The footer widget areas ...
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Axons are covered by a membrane known as an axolemma; the cytoplasm of an axon is called axoplasm. Most axons branch, in some ... The axonal region or compartment, includes the axon hillock, the initial segment, the rest of the axon, and the axon ... yet only one of these neurites is destined to become the axon. It is unclear whether axon specification precedes axon ... An axon is one of two types of cytoplasmic protrusions from the cell body of a neuron; the other type is a dendrite. Axons are ...
Axone may refer to: Axone (arena), sports arena in Montbéliard, France Yr. Robert Lalkovits - Axone, Hungarian musician Akhuni ... a fermented Indian soybean product Axon (disambiguation). ...
Also shown are reconstructions of 50 myelinated axons from the ventroposterolateral nucleus of the thalamus from a similarly ... Also shown are reconstructions of 50 myelinated axons from the ventroposterolateral nucleus of the thalamus from a similarly ...
A list of US medications equivalent to Axone is available on the Drugs.com website. ... Axone is a medicine available in a number of countries worldwide. ... Ingredient matches for Axone. Ceftriaxone. Ceftriaxone is reported as an ingredient of Axone in the following countries:. * ...
Magnetic Stimulation Transmembrane Potential Myelinated Axon Cable Equation Peripheral Axon These keywords were added by ... P.J. Basser, Focal magnetic stimulation of an axon, IEEE Trans. Biomed. Eng. (in press).Google Scholar ... P.J. Basser and B.J. Roth, Stimulation of a myelinated nerve axon by electromagnetic induction, Med. and Biol. Eng. and Comput. ... P.J. Basser, A cable equation for a myelinated axon derived from its microstructure, (in press).Google Scholar ...
... brain and spinal cord injury A foray into plant biology led one researcher to discover that a natural molecule can repair axons ... The axons are stained in green and the tips of the growing axons, called growth cones, are stained in red. ... Kaplan theorized that fusicoccin-A could be an effective way of harnessing 14-3-3 to repair axons. To test this theory, he and ... The team found that the physical bonding of 14-3-3 and GCN1 is an important factor in fusicoccin-A-induced axon growth. Now ...
Steve Tuttle of Axon talks about how the company went from manufacturing weapons solely for consumers to manufacturing ... Arizona Made: Axon, formerly Taser International. Steve Tuttle of Axon talks about how the company went from manufacturing ...
We care about the world in which we live and we want to make it a better place.. We are doing so by fulfilling our mission to accelerate the human side of software development.. We also donate 1% of our profit to different causes, which we as a company, as well as our employees, strongly believe in.. ...
The IT outsourcing industry is very volatile and each year we see new trends reshaping the sector. In 2020, we see some outsourcing practices coming up and others getting stronger. At the same time, we also see some of the prominent outsourcing practices becoming obsolete. This article looks at how the outsourcing industry is changing and getting prepared to embrace the change.. ...
... is a high tech startup formed after a neuro-ophthalmologist, photonics researcher, and ophthalmic entrepreneur got ... Axon Optics is a high tech startup formed after a neuro-ophthalmologist, photonics researcher, and ophthalmic entrepreneur got ... Axon Optics specially tinted glasses block the light that has been implicated in exacerbating sensitivity to light. Control ...
... Matthew Kirkcaldie Matthew.Kirkcaldie at removethis.newcastle.edu.au Thu Jan 1 20:33:47 EST 2004 *Previous ...
An LMU team has shown that the axons of auditory neurons in the brainstem which respond to low and high-frequency sounds differ ... "Our investigation revealed structural differences in the pattern of myelinization of their axons. The axons that are most ... Neurobiology -- tuning of timing in auditory axons. Ludwig-Maximilians-Universität München. Journal. Nature Communications. ... It has generally been assumed that the speed of conduction of action potentials along such axons increases with axon diameter ...
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