Neuromuscular Junction Diseases
Conditions characterized by impaired transmission of impulses at the NEUROMUSCULAR JUNCTION. This may result from disorders that affect receptor function, pre- or postsynaptic membrane function, or ACETYLCHOLINESTERASE activity. The majority of diseases in this category are associated with autoimmune, toxic, or inherited conditions.
The specialized postsynaptic region of a muscle cell. The motor endplate is immediately across the synaptic cleft from the presynaptic axon terminal. Among its anatomical specializations are junctional folds which harbor a high density of cholinergic receptors.
Cell surface proteins that bind acetylcholine with high affinity and trigger intracellular changes influencing the behavior of cells. Cholinergic receptors are divided into two major classes, muscarinic and nicotinic, based originally on their affinity for nicotine and muscarine. Each group is further subdivided based on pharmacology, location, mode of action, and/or molecular biology.
Connections between cells which allow passage of small molecules and electric current. Gap junctions were first described anatomically as regions of close apposition between cells with a narrow (1-2 nm) gap between cell membranes. The variety in the properties of gap junctions is reflected in the number of CONNEXINS, the family of proteins which form the junctions.
A highly variable species of the family Ranidae in Canada, the United States and Central America. It is the most widely used Anuran in biomedical research.
A protein component of the synaptic basal lamina. It has been shown to induce clustering of acetylcholine receptors on the surface of muscle fibers and other synaptic molecules in both synapse regeneration and development.
Direct contact of a cell with a neighboring cell. Most such junctions are too small to be resolved by light microscopy, but they can be visualized by conventional or freeze-fracture electron microscopy, both of which show that the interacting CELL MEMBRANE and often the underlying CYTOPLASM and the intervening EXTRACELLULAR SPACE are highly specialized in these regions. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p792)
A superfamily of various freshwater CRUSTACEA, in the infraorder Astacidea, comprising the crayfish. Common genera include Astacus and Procambarus. Crayfish resemble lobsters, but are usually much smaller.
The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.
Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.
Substances used for their pharmacological actions on any aspect of neurotransmitter systems. Neurotransmitter agents include agonists, antagonists, degradation inhibitors, uptake inhibitors, depleters, precursors, and modulators of receptor function.
Cell membranes associated with synapses. Both presynaptic and postsynaptic membranes are included along with their integral or tightly associated specializations for the release or reception of transmitters.
A species of the family Ranidae which occurs primarily in Europe and is used widely in biomedical research.
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 that catalyzes the hydrolysis of ACETYLCHOLINE to CHOLINE and acetate. In the CNS, this enzyme plays a role in the function of peripheral neuromuscular junctions. EC 22.214.171.124.
Anchoring points where the CYTOSKELETON of neighboring cells are connected to each other. They are composed of specialized areas of the plasma membrane where bundles of the ACTIN CYTOSKELETON attach to the membrane through the transmembrane linkers, CADHERINS, which in turn attach through their extracellular domains to cadherins in the neighboring cell membranes. In sheets of cells, they form into adhesion belts (zonula adherens) that go all the way around a cell.
Membrane-bound compartments which contain transmitter molecules. Synaptic vesicles are concentrated at presynaptic terminals. They actively sequester transmitter molecules from the cytoplasm. In at least some synapses, transmitter release occurs by fusion of these vesicles with the presynaptic membrane, followed by exocytosis of their contents.
Neurotoxic proteins from the venom of the banded or Formosan krait (Bungarus multicinctus, an elapid snake). alpha-Bungarotoxin blocks nicotinic acetylcholine receptors and has been used to isolate and study them; beta- and gamma-bungarotoxins act presynaptically causing acetylcholine release and depletion. Both alpha and beta forms have been characterized, the alpha being similar to the large, long or Type II neurotoxins from other elapid venoms.
The musculofibrous partition that separates the THORACIC CAVITY from the ABDOMINAL CAVITY. Contraction of the diaphragm increases the volume of the thoracic cavity aiding INHALATION.
Plant extracts from several species, including genera STRYCHNOS and Chondodendron, which contain TETRAHYDROISOQUINOLINES that produce PARALYSIS of skeletal muscle. These extracts are toxic and must be used with the administration of artificial respiration.
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.
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
A neuromuscular blocker and active ingredient in CURARE; plant based alkaloid of Menispermaceae.
Myasthenic Syndromes, Congenital
A heterogeneous group of disorders characterized by a congenital defect in neuromuscular transmission at the NEUROMUSCULAR JUNCTION. This includes presynaptic, synaptic, and postsynaptic disorders (that are not of autoimmune origin). The majority of these diseases are caused by mutations of various subunits of the nicotinic acetylcholine receptor (RECEPTORS, NICOTINIC) on the postsynaptic surface of the junction. (From Arch Neurol 1999 Feb;56(2):163-7)
Venoms from animals of the phylum Arthropoda. Those most investigated are from scorpions and spiders of the class Arachnidae and from ant, bee, and wasp families of the Insecta order Hymenoptera. The venoms contain protein toxins, enzymes, and other bioactive substances and may be lethal to man.
An autosomally-encoded 376-kDa cytoskeletal protein that is similar in structure and function to DYSTROPHIN. It is a ubiquitously-expressed protein that plays a role in anchoring the CYTOSKELETON to the PLASMA MEMBRANE.
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.
A disorder of neuromuscular transmission characterized by weakness of cranial and skeletal muscles. Autoantibodies directed against acetylcholine receptors damage the motor endplate portion of the NEUROMUSCULAR JUNCTION, impairing the transmission of impulses to skeletal muscles. Clinical manifestations may include diplopia, ptosis, and weakness of facial, bulbar, respiratory, and proximal limb muscles. The disease may remain limited to the ocular muscles. THYMOMA is commonly associated with this condition. (Adams et al., Principles of Neurology, 6th ed, p1459)
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.
Muscle Fibers, Skeletal
Large, multinucleate single cells, either cylindrical or prismatic in shape, that form the basic unit of SKELETAL MUSCLE. They consist of MYOFIBRILS enclosed within and attached to the SARCOLEMMA. They are derived from the fusion of skeletal myoblasts (MYOBLASTS, SKELETAL) into a syncytium, followed by differentiation.
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 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).
The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm.
Neuroglial cells of the peripheral nervous system which form the insulating myelin sheaths of peripheral axons.
A group of proteins that associate with DYSTROPHIN at the CELL MEMBRANE to form the DYSTROPHIN-ASSOCIATED PROTEIN COMPLEX.
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
One of the two major classes of cholinergic receptors. Nicotinic receptors were originally distinguished by their preference for NICOTINE over MUSCARINE. They are generally divided into muscle-type and neuronal-type (previously ganglionic) based on pharmacology, and subunit composition of the receptors.
Animals, Genetically Modified
A group of homologous proteins which form the intermembrane channels of GAP JUNCTIONS. The connexins are the products of an identified gene family which has both highly conserved and highly divergent regions. The variety contributes to the wide range of functional properties of gap junctions.
A cholinesterase inhibitor used in the treatment of myasthenia gravis and to reverse the effects of muscle relaxants such as gallamine and tubocurarine. Neostigmine, unlike PHYSOSTIGMINE, does not cross the blood-brain barrier.
Neuromuscular Depolarizing Agents
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
Neuromuscular Blocking Agents
Drugs that interrupt transmission of nerve impulses at the skeletal neuromuscular junction. They can be of two types, competitive, stabilizing blockers (NEUROMUSCULAR NONDEPOLARIZING AGENTS) or noncompetitive, depolarizing agents (NEUROMUSCULAR DEPOLARIZING AGENTS). Both prevent acetylcholine from triggering the muscle contraction and they are used as anesthesia adjuvants, as relaxants during electroshock, in convulsive states, etc.
Miniature Postsynaptic Potentials
Postsynaptic potentials generated from a release of neurotransmitters from a presynaptic nerve terminal in the absence of an ACTION POTENTIAL. They may be m.e.p.p.s (miniature EXCITATORY POSTSYNAPTIC POTENTIALS) or m.i.p.p.s (miniature INHIBITORY POSTSYNAPTIC POTENTIALS).
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 family of true frogs of the order Anura. The family occurs worldwide except in Antarctica.
A 43-kDa peptide which is a member of the connexin family of gap junction proteins. Connexin 43 is a product of a gene in the alpha class of connexin genes (the alpha-1 gene). It was first isolated from mammalian heart, but is widespread in the body including the brain.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
A species of the family Ranidae occurring in a wide variety of habitats from within the Arctic Circle to South Africa, Australia, etc.
Zonula Occludens-1 Protein
Cell-surface proteins that bind glutamate and trigger changes which influence the behavior of cells. Glutamate receptors include ionotropic receptors (AMPA, kainate, and N-methyl-D-aspartate receptors), which directly control ion channels, and metabotropic receptors which act through second messenger systems. Glutamate receptors are the most common mediators of fast excitatory synaptic transmission in the central nervous system. They have also been implicated in the mechanisms of memory and of many diseases.
The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.
Drugs that inhibit cholinesterases. The neurotransmitter ACETYLCHOLINE is rapidly hydrolyzed, and thereby inactivated, by cholinesterases. When cholinesterases are inhibited, the action of endogenously released acetylcholine at cholinergic synapses is potentiated. Cholinesterase inhibitors are widely used clinically for their potentiation of cholinergic inputs to the gastrointestinal tract and urinary bladder, the eye, and skeletal muscles; they are also used for their effects on the heart and the central nervous system.
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Botulinum Toxins, Type A
A serotype of botulinum toxins that has specificity for cleavage of SYNAPTOSOMAL-ASSOCIATED PROTEIN 25.
Neurotransmitter receptors located on or near presynaptic terminals or varicosities. Presynaptic receptors which bind transmitter molecules released by the terminal itself are termed AUTORECEPTORS.
Dystrophin-associated proteins that play role in the formation of a transmembrane link between laminin-2 and DYSTROPHIN. Both the alpha and the beta subtypes of dystroglycan originate via POST-TRANSLATIONAL PROTEIN PROCESSING of a single precursor protein.
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.
Tight Junction Proteins
Proteins that take part in the formation or structure of TIGHT JUNCTIONS.
Lambert-Eaton Myasthenic Syndrome
An autoimmune disease characterized by weakness and fatigability of proximal muscles, particularly of the pelvic girdle, lower extremities, trunk, and shoulder girdle. There is relative sparing of extraocular and bulbar muscles. CARCINOMA, SMALL CELL of the lung is a frequently associated condition, although other malignancies and autoimmune diseases may be associated. Muscular weakness results from impaired impulse transmission at the NEUROMUSCULAR JUNCTION. Presynaptic calcium channel dysfunction leads to a reduced amount of acetylcholine being released in response to stimulation of the nerve. (From Adams et al., Principles of Neurology, 6th ed, pp 1471)
An infraorder of CRUSTACEA, in the order DECAPODA comprising the hermit crabs and characterized by a small fifth pair of legs.
Holliday Junction Resolvases
Cytoskeleton specialization at the cytoplasmic side of postsynaptic membrane in SYNAPSES. It is involved in neuronal signaling and NEURONAL PLASTICITY and comprised of GLUTAMATE RECEPTORS; scaffolding molecules (e.g., PSD95, PSD93), and other proteins (e.g., CaCMKII).
Toxic proteins produced from the species CLOSTRIDIUM BOTULINUM. The toxins are synthesized as a single peptide chain which is processed into a mature protein consisting of a heavy chain and light chain joined via a disulfide bond. The botulinum toxin light chain is a zinc-dependent protease which is released from the heavy chain upon ENDOCYTOSIS into PRESYNAPTIC NERVE ENDINGS. Once inside the cell the botulinum toxin light chain cleaves specific SNARE proteins which are essential for secretion of ACETYLCHOLINE by SYNAPTIC VESICLES. This inhibition of acetylcholine release results in muscular PARALYSIS.
The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.
A neuropeptide toxin from the venom of the funnel web spider, Agelenopsis aperta. It inhibits CALCIUM CHANNELS, P-TYPE by altering the voltage-dependent gating so that very large depolarizations are needed for channel opening. It also inhibits CALCIUM CHANNELS, Q-TYPE.
A muscle protein localized in surface membranes which is the product of the Duchenne/Becker muscular dystrophy gene. Individuals with Duchenne muscular dystrophy usually lack dystrophin completely while those with Becker muscular dystrophy have dystrophin of an altered size. It shares features with other cytoskeletal proteins such as SPECTRIN and alpha-actinin but the precise function of dystrophin is not clear. One possible role might be to preserve the integrity and alignment of the plasma membrane to the myofibrils during muscle contraction and relaxation. MW 400 kDa.
The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.
An edible species of the family Ranidae, occurring in Europe and used extensively in biomedical research. Commonly referred to as "edible frog".
Receptor Protein-Tyrosine Kinases
One of two types of muscle in the body, characterized by the array of bands observed under microscope. Striated muscles can be divided into two subtypes: the CARDIAC MUSCLE and the SKELETAL MUSCLE.
Myasthenia Gravis, Autoimmune, Experimental
Any autoimmune animal disease model used in the study of MYASTHENIA GRAVIS. Injection with purified neuromuscular junction acetylcholine receptor (AChR) (see RECEPTORS, CHOLINERGIC) components results in a myasthenic syndrome that has acute and chronic phases. The motor endplate pathology, loss of acetylcholine receptors, presence of circulating anti-AChR antibodies, and electrophysiologic changes make this condition virtually identical to human myasthenia gravis. Passive transfer of AChR antibodies or lymphocytes from afflicted animals to normals induces passive transfer experimental autoimmune myasthenia gravis. (From Joynt, Clinical Neurology, 1997, Ch 54, p3)
Microscopy, Electron, Transmission
A general term encompassing lower MOTOR NEURON DISEASE; PERIPHERAL NERVOUS SYSTEM DISEASES; and certain MUSCULAR DISEASES. Manifestations include MUSCLE WEAKNESS; FASCICULATION; muscle ATROPHY; SPASM; MYOKYMIA; MUSCLE HYPERTONIA, myalgias, and MUSCLE HYPOTONIA.
Vesicle-Associated Membrane Protein 1
A family of peptides originally found as factors that stimulate the phosphorylation of the erbB-2 receptor (RECEPTORS, ERBB-2). Multiple variant forms of NEUREGULINS occur due to alternative splicing of their mRNAs. The NEUREGULINS include products from the three known genes (NGR1; NGR2 and NGR3).
Muscular Atrophy, Spinal
A group of disorders marked by progressive degeneration of motor neurons in the spinal cord resulting in weakness and muscular atrophy, usually without evidence of injury to the corticospinal tracts. Diseases in this category include Werdnig-Hoffmann disease and later onset SPINAL MUSCULAR ATROPHIES OF CHILDHOOD, most of which are hereditary. (Adams et al., Principles of Neurology, 6th ed, p1089)
Arthropods of the class ARACHNIDA, order Araneae. Except for mites and ticks, spiders constitute the largest order of arachnids, with approximately 37,000 species having been described. The majority of spiders are harmless, although some species can be regarded as moderately harmful since their bites can lead to quite severe local symptoms. (From Barnes, Invertebrate Zoology, 5th ed, p508; Smith, Insects and Other Arthropods of Medical Importance, 1973, pp424-430)
Caenorhabditis elegans Proteins
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.
Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
Amino Acid Sequence
Fluorescent Antibody Technique
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
Therapeutic introduction of ions of soluble salts into tissues by means of electric current. In medical literature it is commonly used to indicate the process of increasing the penetration of drugs into surface tissues by the application of electric current. It has nothing to do with ION EXCHANGE; AIR IONIZATION nor PHONOPHORESIS, none of which requires current.
GA-Binding Protein Transcription Factor
A heterotetrameric transcription factor composed of two distinct proteins. Its name refers to the fact it binds to DNA sequences rich in GUANINE and ADENINE. GA-binding protein integrates a variety of SIGNAL TRANSDUCTION PATHWAYS and regulates expression of GENES involved in CELL CYCLE control, PROTEIN BIOSYNTHESIS, and cellular METABOLISM.
Calcium Channels, P-Type
CALCIUM CHANNELS located within the PURKINJE CELLS of the cerebellum. They are involved in stimulation-secretion coupling of neurons.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
A potent inhibitor of the high affinity uptake system for CHOLINE. It has less effect on the low affinity uptake system. Since choline is one of the components of ACETYLCHOLINE, treatment with hemicholinium can deplete acetylcholine from cholinergic terminals. Hemicholinium 3 is commonly used as a research tool in animal and in vitro experiments.
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 Adhesion Molecules, Neuronal
Surface ligands that mediate cell-to-cell adhesion and function in the assembly and interconnection of the vertebrate nervous system. These molecules promote cell adhesion via a homophilic mechanism. These are not to be confused with NEURAL CELL ADHESION MOLECULES, now known to be expressed in a variety of tissues and cell types in addition to nervous tissue.
Venoms from snakes of the family Elapidae, including cobras, kraits, mambas, coral, tiger, and Australian snakes. The venoms contain polypeptide toxins of various kinds, cytolytic, hemolytic, and neurotoxic factors, but fewer enzymes than viper or crotalid venoms. Many of the toxins have been characterized.
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.
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.
Calcium Channels, N-Type
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.
Calcium-dependent cell adhesion proteins. They are important in the formation of ADHERENS JUNCTIONS between cells. Cadherins are classified by their distinct immunological and tissue specificities, either by letters (E- for epithelial, N- for neural, and P- for placental cadherins) or by numbers (cadherin-12 or N-cadherin 2 for brain-cadherin). Cadherins promote cell adhesion via a homophilic mechanism as in the construction of tissues and of the whole animal body.
A nerve which originates in the lumbar and sacral spinal cord (L4 to S3) and supplies motor and sensory innervation to the lower extremity. The sciatic nerve, which is the main continuation of the sacral plexus, is the largest nerve in the body. It has two major branches, the TIBIAL NERVE and the PERONEAL NERVE.
The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.
Toxic substances from microorganisms, plants or animals that interfere with the functions of the nervous system. Most venoms contain neurotoxic substances. Myotoxins are included in this concept.
2-Chloroadenosine. A metabolically stable analog of adenosine which acts as an adenosine receptor agonist. The compound has a potent effect on the peripheral and central nervous system.
An antihelminthic drug that has been tried experimentally in rheumatic disorders where it apparently restores the immune response by increasing macrophage chemotaxis and T-lymphocyte function. Paradoxically, this immune enhancement appears to be beneficial in rheumatoid arthritis where dermatitis, leukopenia, and thrombocytopenia, and nausea and vomiting have been reported as side effects. (From Smith and Reynard, Textbook of Pharmacology, 1991, p435-6)
rab3A GTP-Binding Protein
The most abundant member of the RAB3 GTP-BINDING PROTEINS. It is involved in calcium-dependent EXOCYTOSIS and is localized to neurons and neuroendocrine cells. This enzyme was formerly listed as EC 126.96.36.199.
Nervous System Physiological Phenomena
Characteristic properties and processes of the NERVOUS SYSTEM as a whole or with reference to the peripheral or the CENTRAL NERVOUS SYSTEM.
A darkly stained mat-like EXTRACELLULAR MATRIX (ECM) that separates cell layers, such as EPITHELIUM from ENDOTHELIUM or a layer of CONNECTIVE TISSUE. The ECM layer that supports an overlying EPITHELIUM or ENDOTHELIUM is called basal lamina. Basement membrane (BM) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. BM, composed mainly of TYPE IV COLLAGEN; glycoprotein LAMININ; and PROTEOGLYCAN, provides barriers as well as channels between interacting cell layers.
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
A vague complaint of debility, fatigue, or exhaustion attributable to weakness of various muscles. The weakness can be characterized as subacute or chronic, often progressive, and is a manifestation of many muscle and neuromuscular diseases. (From Wyngaarden et al., Cecil Textbook of Medicine, 19th ed, p2251)
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).
Large, noncollagenous glycoprotein with antigenic properties. It is localized in the basement membrane lamina lucida and functions to bind epithelial cells to the basement membrane. Evidence suggests that the protein plays a role in tumor invasion.
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 outermost cytoplasmic layer of the SCHWANN CELLS covering NERVE FIBERS.
A family of structurally related neurotoxic peptides from mollusk venom that inhibit voltage-activated entry of calcium into the presynaptic membrane. They selectively inhibit N-, P-, and Q-type calcium channels.
A synthetic nondepolarizing blocking drug. The actions of gallamine triethiodide are similar to those of TUBOCURARINE, but this agent blocks the cardiac vagus and may cause sinus tachycardia and, occasionally, hypertension and increased cardiac output. It should be used cautiously in patients at risk from increased heart rate but may be preferred for patients with bradycardia. (From AMA Drug Evaluations Annual, 1992, p198)
Quaternary Ammonium Compounds
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
Survival of Motor Neuron 1 Protein
A SMN complex protein that is essential for the function of the SMN protein complex. In humans the protein is encoded by a single gene found near the inversion telomere of a large inverted region of CHROMOSOME 5. Mutations in the gene coding for survival of motor neuron 1 protein may result in SPINAL MUSCULAR ATROPHIES OF CHILDHOOD.
A rapid-onset, short-acting cholinesterase inhibitor used in cardiac arrhythmias and in the diagnosis of myasthenia gravis. It has also been used as an antidote to curare principles.
An integral membrane protein that is localized to TIGHT JUNCTIONS, where it plays a role in controlling the paracellular permeability of polarized cells. Mutations in the gene for claudin-1 are associated with Neonatal Ichthyosis-Sclerosing Cholangitis (NISCH) Syndrome.
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)
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.
Calcium Channels, R-Type
CALCIUM CHANNELS located in the neurons of the brain. They are inhibited by the marine snail toxin, omega conotoxin MVIIC.
Cell Membrane Permeability
Type III intermediate filament proteins that assemble into neurofilaments, the major cytoskeletal element in nerve axons and dendrites. They consist of three distinct polypeptides, the neurofilament triplet. Types I, II, and IV intermediate filament proteins form other cytoskeletal elements such as keratins and lamins. It appears that the metabolism of neurofilaments is disturbed in Alzheimer's disease, as indicated by the presence of neurofilament epitopes in the neurofibrillary tangles, as well as by the severe reduction of the expression of the gene for the light neurofilament subunit of the neurofilament triplet in brains of Alzheimer's patients. (Can J Neurol Sci 1990 Aug;17(3):302)
Gene Expression Regulation, Developmental
Calcium Channels, Q-Type
CALCIUM CHANNELS located in the neurons of the brain.
Green Fluorescent Proteins
Excitatory Postsynaptic Potentials
Depolarization of membrane potentials at the SYNAPTIC MEMBRANES of target neurons during neurotransmission. Excitatory postsynaptic potentials can singly or in summation reach the trigger threshold for ACTION POTENTIALS.
Amyotrophic Lateral Sclerosis
A degenerative disorder affecting upper MOTOR NEURONS in the brain and lower motor neurons in the brain stem and SPINAL CORD. Disease onset is usually after the age of 50 and the process is usually fatal within 3 to 6 years. Clinical manifestations include progressive weakness, atrophy, FASCICULATION, hyperreflexia, DYSARTHRIA, dysphagia, and eventual paralysis of respiratory function. Pathologic features include the replacement of motor neurons with fibrous ASTROCYTES and atrophy of anterior SPINAL NERVE ROOTS and corticospinal tracts. (From Adams et al., Principles of Neurology, 6th ed, pp1089-94)