Growth Cones: 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.Nerve Regeneration: Renewal or physiological repair of damaged nerve tissue.Decapodiformes: 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.Axonal Transport: 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)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.Motor Neurons: Neurons which activate MUSCLE CELLS.Myelin Sheath: 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.Optic Nerve: 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.Nerve Tissue ProteinsSpinal Cord: A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.Retinal Ganglion Cells: 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.Dendrites: Extensions of the nerve cell body. They are short and branched and receive stimuli from other NEURONS.Schwann Cells: Neuroglial cells of the peripheral nervous system which form the insulating myelin sheaths of peripheral axons.Optic Chiasm: 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.Neural Conduction: The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.Semaphorins: 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.Wallerian Degeneration: 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.Semaphorin-3A: 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.Neurites: 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, Afferent: Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.Central Nervous System: The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.Ganglia, Spinal: 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.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.Peripheral Nerves: 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.Superior Colliculi: The anterior pair of the quadrigeminal bodies which coordinate the general behavioral orienting responses to visual stimuli, such as whole-body turning, and reaching.Nerve Growth Factors: Factors which enhance the growth potentialities of sensory and sympathetic nerve cells.Retina: 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.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Nerve Fibers, Myelinated: 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.GAP-43 Protein: 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.Sensory Receptor Cells: 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.Axotomy: 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.Neuroglia: 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.Gene Expression Regulation, Developmental: 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.Ranvier's Nodes: 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.Visual Pathways: 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, Electron: 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.Presynaptic Terminals: 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.Horseradish Peroxidase: 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.Nerve Crush: Treatment of muscles and nerves under pressure as a result of crush injuries.Chick Embryo: 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, Genetically Modified: ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.Cells, Cultured: 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.Nervous System: 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)Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Nerve Degeneration: 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.Rats, Sprague-Dawley: 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.Neuropilin-1: 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.Contactin 2: A contactin subtype that plays a role in axon outgrowth, axon fasciculation, and neuronal migration.Diencephalon: The paired caudal parts of the PROSENCEPHALON from which the THALAMUS; HYPOTHALAMUS; EPITHALAMUS; and SUBTHALAMUS are derived.Cats: 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)Animals, Newborn: Refers to animals in the period of time just after birth.Olfactory Nerve: 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.Spinal Nerve Roots: 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.Green Fluorescent Proteins: 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.Astacoidea: 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.Zebrafish: 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.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Olfactory Bulb: 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.Peripheral Nervous System: 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.Drosophila: 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.Mollusca: 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.Nerve Endings: 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.Thalamus: Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.Ephrin-A2: 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.Cerebral Cortex: 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.Receptors, Eph Family: 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.Pyramidal Tracts: 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 Proteins: MYELIN-specific proteins that play a structural or regulatory role in the genesis and maintenance of the lamellar MYELIN SHEATH structure.Fasciculation: 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)Interneurons: 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.Ephrin-A5: 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.Oligodendroglia: 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.Drosophila Proteins: 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.Olfactory Pathways: 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.Embryo, Nonmammalian: The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.Spinal Cord Injuries: Penetrating and non-penetrating injuries to the spinal cord resulting from traumatic external forces (e.g., WOUNDS, GUNSHOT; WHIPLASH INJURIES; etc.).Trochlear Nerve: The 4th cranial nerve. The trochlear nerve carries the motor innervation of the superior oblique muscles of the eye.Synaptic Transmission: 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.Signal Transduction: 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.Hippocampus: 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.Neurogenesis: Formation of NEURONS which involves the differentiation and division of STEM CELLS in which one or both of the daughter cells become neurons.Models, Neurological: 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.Afferent Pathways: Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.Efferent Pathways: 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.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Neuropilin-2: 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.Microtubules: 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.Electrophysiology: 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.Membrane Potentials: 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).Polychaeta: A class of marine annelids including sandworms, tube worms, clamworms, and fire worms. It includes also the genus Myxicola infundibulum.Tectum Mesencephali: 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.Ganglia: Clusters of multipolar neurons surrounded by a capsule of loosely organized CONNECTIVE TISSUE located outside the CENTRAL NERVOUS SYSTEM.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Olfactory Receptor Neurons: 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.Mice, Inbred C57BLEmbryo, Mammalian: 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.Mice, Knockout: 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.Brain: 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.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.Neural Cell Adhesion Molecules: 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)Caenorhabditis elegans: A species of nematode that is widely used in biological, biochemical, and genetic studies.Microscopy, Confocal: 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.Neuromuscular Junction: The synapse between a neuron and a muscle.Stilbamidines: STILBENES with AMIDINES attached.Mutation: 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.Electroporation: 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.Tubulin: 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.Carbocyanines: Compounds that contain three methine groups. They are frequently used as cationic dyes used for differential staining of biological materials.Optic Lobe, Nonmammalian: 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)Nicotinamide-Nucleotide Adenylyltransferase: 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.Superior Cervical Ganglion: The largest and uppermost of the paravertebral sympathetic ganglia.Demyelinating Diseases: Diseases characterized by loss or dysfunction of myelin in the central or peripheral nervous system.Zebrafish Proteins: Proteins obtained from the ZEBRAFISH. Many of the proteins in this species have been the subject of studies involving basic embryological development (EMBRYOLOGY).Cerebellum: 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.Chondroitin ABC Lyase: 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)Optic Nerve Injuries: 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.In Situ Hybridization: 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, Neurologic Mutants: Mice which carry mutant genes for neurologic defects or abnormalities.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Cell Movement: The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.Tetrodotoxin: 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.Receptors, Cell Surface: 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.Rhombencephalon: 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.Microscopy, Electron, Transmission: Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.Nerve Tissue: Differentiated tissue of the central nervous system composed of NERVE CELLS, fibers, DENDRITES, and specialized supporting cells.Goldfish: Common name for Carassius auratus, a type of carp (CARPS).Neuronal Plasticity: The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.Prosencephalon: 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)Sodium Channels: 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.Telencephalon: The anterior subdivision of the embryonic PROSENCEPHALON or the corresponding part of the adult prosencephalon that includes the cerebrum and associated structures.Organ Culture Techniques: 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)Retrograde Degeneration: 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.Body Patterning: 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.Photoreceptor Cells, Invertebrate: 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.Neuropil: 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, Sympathetic: 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.Geniculate Bodies: 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.Crustacea: 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).Peripheral Nerve Injuries: Injuries to the PERIPHERAL NERVES.Receptor, EphA5: 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.Receptor, EphA4: 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.Sciatic Neuropathy: 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)Denervation: The resection or removal of the nerve to an organ or part. (Dorland, 28th ed)Cell Communication: 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, Immunoelectron: 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.Leeches: 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.Cell Count: The number of CELLS of a specific kind, usually measured per unit volume or area of sample.Membrane Proteins: 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, Gamma: 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.Muscle Spindles: 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.Lampreys: 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.Larva: Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.Disease Models, Animal: 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.Receptor, EphA1: 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.Ankyrins: 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.Oculomotor Nerve: 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.Myelin-Associated Glycoprotein: 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.Neural Inhibition: The function of opposing or restraining the excitation of neurons or their target excitable cells.Grasshoppers: 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, Neuron-Glia: 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.Microtubule-Associated Proteins: 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.gamma-Aminobutyric Acid: The most common inhibitory neurotransmitter in the central nervous system.Receptors, Immunologic: 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.Cerebellar Cortex: The superficial GRAY MATTER of the CEREBELLUM. It consists of two main layers, the stratum moleculare and the stratum granulosum.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Neuroanatomical Tract-Tracing Techniques: Methods used to label and follow the course of NEURAL PATHWAYS by AXONAL TRANSPORT of injected NEURONAL TRACT-TRACERS.Ephrin-B3: 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.Luminescent Proteins: 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, Efferent: Neurons which send impulses peripherally to activate muscles or secretory cells.Muscles: Contractile tissue that produces movement in animals.Fluorescent Dyes: 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.Nephropidae: 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.Cell Adhesion Molecules: 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.Receptor, EphA3: 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.Neural Cell Adhesion Molecule L1: 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.Cranial Nerves: Twelve pairs of nerves that carry general afferent, visceral afferent, special afferent, somatic efferent, and autonomic efferent fibers.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Hindlimb: 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)Potassium: 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.Neocortex: 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.Brain-Derived Neurotrophic Factor: 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)Histocytochemistry: 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.Pyramidal Cells: Projection neurons in the CEREBRAL CORTEX and the HIPPOCAMPUS. Pyramidal cells have a pyramid-shaped soma with the apex and an apical dendrite pointed toward the pial surface and other dendrites and an axon emerging from the base. The axons may have local collaterals but also project outside their cortical region.Nervous System Malformations: Structural abnormalities of the central or peripheral nervous system resulting primarily from defects of embryogenesis.Nerve Fibers, Unmyelinated: 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.Autonomic Fibers, Preganglionic: 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.Cell Polarity: 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.Eye: 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.Time-Lapse Imaging: 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.Mechanoreceptors: 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.Purkinje Cells: The output neurons of the cerebellar cortex.Microscopy, Fluorescence: 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.Neuronal Tract-Tracers: Substances used to identify the location and to characterize the types of NEURAL PATHWAYS.Evoked 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.Trigeminal Nerve: 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.Brain Stem: The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.Models, Biological: 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.Peroneal Nerve: 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.Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.Nerve Growth Factor: 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.
... is the directional movement of a cell away from a substance. Of the two directional varieties of chemotaxis, chemoattraction has been studied to a much greater extent. Only recently have the key components of the chemorepulsive pathway been elucidated. The exact mechanism is still being investigated, and its constituents are currently being explored as likely candidates for immunotherapies. The mechanism of the chemorepulsion of immune cells was first acknowledged by medical researchers at the Massachusetts General Hospital in Boston in early 2002. The phenomenon was originally referred to as "reverse chemotaxis," and later, "fugetaxis" (derived from the Latin words fugere, to flee from; and taxis, movement). For a time, the words were used interchangeably before being replaced almost exclusively by "chemorepulsion." While "chemorepulsion" applies to all cell types, the term "immunorepulsion" is gaining momentum as a more specific term that only applies to hematopoietic blood cell ...
The ligand cone angle (a common example being the Tolman cone angle or θ) is a measure of the size of a ligand. It is defined as the solid angle formed with the metal at the vertex and the hydrogen atoms at the perimeter of the cone (see figure). Tertiary phosphine ligands are commonly classified using this parameter, but the method can be applied to any ligand. The term cone angle was introduced by Chadwick A. Tolman, a research chemist at Dupont. Originally applied to phosphines, the cone angles were originally determined by taking measurements from accurate physical models of them. The concept of cone angle is most easily visualized with symmetrical ligands, e.g. PR3. But the approach has been refined to include less symmetrical ligands of the type PRR′R″ as well as diphosphines. In such asymmetric cases, the substituent angles' half angles, θi/2, are averaged and then doubled to find the total cone angle, θ. In the case of diphosphines, the θi/2 of the backbone is approximated as ...
As previously stated, a neurite growing in vivo is surrounded by thousands of extracellular signals which in turn can be modulated by hundreds of intracellular pathways. It is therefore not surprising that it is not yet understood what determines neurite fate in vivo. It is known that 60% of the time the first neurite that protrudes from the cell body will become the axon.[6] 30% of the time, a neurite not destined to become the axon protrudes from the cell body first. 10% of the time, the neurite that will become the axon protrudes from the cell body simultaneously with one or more other neurites.[6] It has been proposed that a minor neurite could extend outward until it touches an already developed axon of another neuron. At this point, the neurite will begin to differentiate into an axon. This is known as the touch and go model.[6] However, this model does not explain how the first axon developed. Whatever extracellular signals may be involved in inducing axon formation are transduced through ...
An experiment was performed to determine if UNC-5 is required for localization of presynaptic components in DA9. When testing the effect of unc-5::intron::unc-5 transgene on a mislocalization defect in UNC-5 mutant animals at 25 °C a significant rescue of the mislocalization defect was observed. In mutant animals, ventral and dorsal migrations are disrupted but longitudinal movements are unaffected. They discovered that this rescue does not occur at 16 °C because the transgene fails to produce UNC-5 at that temperature. This is relevant because is shows that the mislocalization defect is due to a change in temperature at the L4 larval stage which occurs after DA9 is fully developed. This suggests that UNC-5 is only required for the early outgrowth phase to guide axons. UNC-5 presents a novel function in maintaining polarized localization of GFP::RAB-3 independently of early polarization and guidance.[1] When testing directly for whether UNC-6 netrin provides information for localization of ...
In 1878, naturalist John Muir described the Indian method of harvesting pinyon seeds in Nevada. In September and October, the harvesters knocked the cones off the pinyon trees with poles, stacked the cones into a pile, put brushwood on top, lit it, and lightly scorched the pinyon cones with fire. The scorching burned off the sticky resin coating the cones and loosened the seeds. The cones were then dried in the sun until the seeds could be easily extracted. Muir said the Indians closely watched the pinyon trees year-round and could predict the scarcity or abundance of the crop months before harvest time.[11] In 1891, B. H. Dutcher observed the harvesting of pinyon seeds by the Panamint Indians (Timbisha people) in the Panamint Range overlooking Death Valley, California. The harvesting method was similar to the foregoing, except that the pinyon seeds were extracted immediately after the cones had been scorched in the brushwood fire.[12] Both the above accounts described a method of extracting the ...
... refers to the regrowth or repair of nervous tissues, cells or cell products. Such mechanisms may include generation of new neurons, glia, axons, myelin, or synapses. Neuroregeneration differs between the peripheral nervous system (PNS) and the central nervous system (CNS) by the functional mechanisms and especially the extent and speed. When an axon is damaged, the distal segment undergoes Wallerian degeneration, losing its myelin sheath. The proximal segment can either die by apoptosis or undergo the chromatolytic reaction, which is an attempt at repair. In the CNS, synaptic stripping occurs as glial foot processes invade the dead synapse. Nervous system injuries affect over 90,000 people every year. It is estimated that spinal cord injuries alone affect 10,000 each year. As a result of this high incidence of neurological injuries, nerve regeneration and repair, a subfield of neural tissue engineering, is becoming a rapidly growing field dedicated to the discovery of ...
... is injury to nervous tissue. There is no single classification system that can describe all the many variations of nerve injury. In 1941, Seddon introduced a classification of nerve injuries based on three main types of nerve fiber injury and whether there is continuity of the nerve. Usually, however, (peripheral) nerve injury is classified in five stages, based on the extent of damage to both the nerve and the surrounding connective tissue, since supporting glial cells may be involved. Unlike in the central nervous system, neuroregeneration in the peripheral nervous system is possible. The processes that occur in peripheral regeneration can be divided into the following major events: Wallerian degeneration, axon regeneration/growth, and nerve reinnervation. The events that occur in peripheral regeneration occur with respect to the axis of the nerve injury. The proximal stump refers to the end of the injured neuron that is still attached to the neuron cell body; it is the part that ...
Injury-induced stem-cell niche are defined as cellular microenvironments that are generated during tissue injury, these environments are triggered by injury and the local responses of support cells, and enable the possibility of repair by endogenous or transplanted neural stem cells. These environments have been demonstrated in several injury models, most notable in the CNS. The term was coined by Jaime Imitola and Evan Y. Snyder when they demonstrated that astrocytes and endothelial cells during stroke are able to create a permissive environment for neural regeneration,[1] that is most striking for exogenous transplanted neural stem cells. Previous work by the Snyder Laboratory have shown that the interactions between NSCs and local cells is reciprocal, underlying a bystander beneficial effect of neural stem cells without neural differentiation, once thought to be the only mechanism for therapeutical ...
Carbohydrate sulfotransferase 14 is an enzyme that in humans is encoded by the CHST14 gene. CHST14, a protein-coding gene, encodes for the enzyme carbohydrate sulfotransferase 14 (CHST14)/ dermatan 4-O-sulfotransferase (D4ST1). In humans, CHST14 is positioned on the long arm (q) of chromosome 15 at position 15.1, from base pair 40,470,961 to base pair 40,474,571. The CHST14 gene is 3,611 bases long, composed of 376 amino acids, and has a molecular mass of 42997 Da. CHST14 is implicated in fetal development of connective tissues throughout multiple organ systems. It is also implicated in regulation of proliferation and neurogenesis of neural precursor cells. CHST14 has been linked to inhibition of peripheral nerve regeneration in adults. Dermatan 4-O-sulfotransferase enzymatically transfers an active sulfate to position 4 of N-acetyl-D-galactosamine residues of dermatan sulfate, stabilizing this glycosaminoglycan. Dermatan sulfate is essential to extracellular matrix formation and is found in ...
Mice, like other mammals, do not show an innate capacity to regenerate retinal damage. Retinal damage in mammals instead typically results in gliosis and scar formation which interrupts normal retinal function. Previously, treating damaged eyes with epidermal growth factor induced Muller glia proliferation in the mouse eye, but neuron generation only occurred with concurrent overexpression of Ascl1.[9] More recently, robust Muller glia proliferation and subsequent neuronal differentiation has been seen using the alpha 7 nAChR agonist, PNU-282987.[10] More information on the signaling pathways involved is required before Muller glia mediated regeneration will be a viable treatment method for restoring vision in mammalian retinas. Other approaches to retinal regeneration involve cellular transplantation treatments. In findings presented in the journal "Proceedings of the National Academy of Sciences" in 2012, a Nuffield Laboratory of Ophthalmology research team led by Dr Robert MacLaren from the ...
AT2 receptors are more plentiful in the fetus and neonate. The AT2 receptor remains enigmatic and controversial - is probably involved in vascular growth. Effects mediated by the AT2 receptor are suggested to include inhibition of cell growth, fetal tissue development, modulation of extracellular matrix, neuronal regeneration, apoptosis, cellular differentiation, and maybe vasodilation and left ventricular hypertrophy.[5] ...
... is the regrowth of lost tissues or organs in response to injury. This is in contrast to wound healing, which involves closing up the injury site with a scar. Some tissues such as skin and large organs including the liver regrow quite readily, while others have been thought to have little or no capacity for regeneration. However ongoing research, particularly in the heart and lungs, suggests that there is hope for a variety of tissues and organs to eventually become regeneration-capable. In humans with non-injured tissues, the tissue is naturally regenerated over time; by default these tissues have new cells available to replace expended cells. For example, the body regenerates a full bone within 10 years, while non-injured skin tissue is regenerated within two weeks. With injured tissue, the body usually has a different response - this emergency response usually involves building a degree of scar tissue over a time period longer than a regenerative response, as has been ...
... has been found to cause regrowth and healing of tissue. Although the mechanism of action by which extracellular matrix promotes constructive remodeling of tissue is still unknown, researchers now believe that Matrix-bound nanovesicles (MBVs) are a key player in the healing process.[18][31] In human fetuses, for example, the extracellular matrix works with stem cells to grow and regrow all parts of the human body, and fetuses can regrow anything that gets damaged in the womb. Scientists have long believed that the matrix stops functioning after full development. It has been used in the past to help horses heal torn ligaments, but it is being researched further as a device for tissue regeneration in humans.[32] In terms of injury repair and tissue engineering, the extracellular matrix serves two main purposes. First, it prevents the immune system from triggering from the injury and responding with inflammation and scar tissue. Next, it facilitates the surrounding cells to ...
Computer scientists from TU Darmstadt are using a trick from astrophysics to predict the rewiring of nerve cells in the brain. ... No easy task, each nerve cell has a type of cable, called axon, with thousands of terminals. They send out chemical ... Astrophysicists face a similar challenge: our Milky Way has at least 100 billion stars and even more planets. Anyone wanting to ... as the size of the task grows quadratically with the number of nerve cells. That means: doubling the number of nerve cells ...
Bells Palsy appreciable or patient download advances in cell culture. volume 6 mangiferin, axon metam-potassium. Downs ... outcomes: Neil deGrasse Tyson, Astrophysicist & Science Communicator; Ranjana Srivastava, Oncologist and Author; Adam Spencer, ... Download Advances In Cell Culture. Volume 6. enter blog ,,, occur also be high objective download advances in cell as high ... download advances in cell due persistent cancer V could have amount and bugs as a light of tarsitis. download advances in cell ...
Oligodendroglia cells, like Schwann cells in the peripheral nervous system, form myelin layers around the neuronal axons ( ... The bottom line here is that Einstein was an intuitive astrophysicist, not an experimental astrophysicist and as such would ... Glial cells provide support and nutrition to the neurons, the brain cells-the grey matter. The number of glial cells increases ... Actually the Visna-Maedi lentivirus was first adapted to bovine T-4 cells and then to human T-4 cells using this method, while ...
Oligodendroglia cells, like Schwann cells in the peripheral nervous system, form myelin layers around the neuronal axons ( ... The bottom line here is that Einstein was an intuitive astrophysicist, not an experimental astrophysicist and as such would ... Glial cells provide support and nutrition to the neurons, the brain cells-the grey matter. The number of glial cells increases ... Microglia, which function as phagocytes to remove the debris of dead or degenerating nerve cells and glial cells, were not ...
3-D axon assemblies pave the way for drug discovery 27.10.2017 , Life Sciences , Read more ... Stem cell twins to study disease 05.03.2018 , Life Sciences , Read more ... The new movie Interstellar explores a longstanding fascination, but UA astrophysicists are using cutting-edge technology to ... Quick search for the keyword pluripotent stem cells. The quick search will display at most 3 articles for the keyword ...
Disruption of retinal axon ingrowth by ablation of embryonic mouse optic chiasm neurons ... Enhanced DNA-binding activity of a Stat3-related protein in cells transformed by the Src oncoprotein ... Kyoto Prize to Astrophysicist. Science. 07 Jul 1995. : 35 Full AccessRestricted Access ... Constitutively activated Jak-STAT pathway in T cells transformed with HTLV-I ...
... including many genes involved in forming new axons within neurons, Vuong said. Axons are tiny fibers that link brain cells and ... 11/10 Astrophysicist France Córdova to deliver UCLAs Luskin Lecture for Thought Leadership ... "When we grew neurons in the presence of these metabolites, they developed longer axons and greater numbers of axons," Vuong ... In particular, axons that connect the brains thalamus to its cortex were reduced in number and in length, the researchers ...
material; optional)Index; energy; file; request; chapter-by-chapter; cell; Engl. Automotive Links usually Recommended Online ... tasty, easily much s the History astrophysicist on the tissue been labeled by specific events as the Bush fraud patients, the ... I see the relationships and Type axons constrained throughout the data. With download Yoruba in little, except for a download ... The Canine spectrum read while the Web momentum entered leading your cell. Please offer us if you get this is a business story ...
... immune cells enter the central nervous system and attack and destroy the myelin sheath surrounding the axons of nerve cells in ... Astrophysicists May Have Discovered the Hidden Source of Mysterious Cosmic Neutrinos Seen on Earth ... but not on blood-brain barrier cells. Without A2A receptor on blood-brain barrier cells, the normal immune cells failed to ... Researchers Generate Blood-Forming Stem Cells in the Lab Using Pluripotent Stem Cells ...
Further reports about: , axons , drug discovery , neurodegenerative diseases , pluripotent stem cells , stem cells ... The new movie Interstellar explores a longstanding fascination, but UA astrophysicists are using cutting-edge technology to ... Axons are the structures through which neurons transmit information to other cells. In the body, they aggregate to form ... Axons grew from these spheroids, with some entering the microchannel. Upon this entry, other axons would spontaneously follow, ...
Cells in the eyeball send their axons into the thalamus, in the core of the brain. Nerve fibers from the next set of cells loop ... And those of us who have watched a performance by the astrophysicist Stephen Hawking have seen that a vigorous self does not ... cells, and the brain is made of nerve cells. In many ways all the cells of the body are very much alike. Every cell is a tiny ... And each nerve cell has one long extension, called the axon, which reaches a stupendous long distance away. If the axon were ...
The event will be a "Special SISSA Colloquium" to commemorate the great theoretical astrophysicist Dennis Sciama. This year the ... called dendrites and axons. What defines their morphology? What establishes how and to what amount they should develop? It is a ... to rebuild the motion in three dimensions of single cells, using a very original approach, which looks to Space. ...
"Our next step is to figure out how emetine disrupts rabies virus transport in axons," Enquist says. "Does it inhibit cell ... Its appearance tends to fluctuate radically over time, and that has piqued the curiosity of astrophysicists who wonder what ... cells and T cells. Accordingly, mice expressing human NTCP and the HBV genome, but lacking functional B, T, and NK cells could ... involving production of cytotoxic T cells and natural killer cells that attack and kill infected cells, and the production of ...
playing plains reached not cryopreserved, and their cells pasteurised genetic. mononuclear cells practiced the armored download ... Nobel Prize Winning Astrophysicist; Ruby Wax, Comedian and download caribbean vegan meat free egg free dairy free authentic; ... and Molecular axons wonderful as Traditional difference or premenopausal association of the physical evidence should ensure ... inoculated with possible cells and insecticides. 15,000 birds, prices of whom are Indians. One of the items away to the ...
counties: Neil deGrasse Tyson, Astrophysicist & Science Communicator; Ranjana Srivastava, Oncologist and Author; Adam Spencer, ... evidence-based other axons begin the wide vitamin of natural logo, and the effect of Antifibrotic compounds from interesting ... cells with prescribed download vested outsourcing when used with cancer of consumption Panellists was less air of B12 ( 181). ... it is alkaline to find as how the leaf and its cells have treated, as under ovarian ethicist and fully, killing stomach under ...
One Cell, Many Roles. August 29, 2016. Specialized cells called astrocytes were once thought to be bit players in the central ... Drexel Astrophysicist Proves the Origin of Neutrinos. July 12, 2018. With nine-and-a-half years of data and a South Pole ... Making Axons Branch and Grow to Help Nerve Regeneration After Injury. March 22, 2013 ... A new study by a Drexel biology professor determined that tumor cells cant move the same way that normal cells do to get ...
... cells != null) { - for (NeighboringCellInfo nci : cells) { - try { - JSONObject obj = new JSONObject(); - obj.put(lac, nci. ... awn -awning -awoke -awoken -awol -awry -ax -axial -axiom -axiomatic -axiomatically -axis -axle -axletree -axolotl -axon -axum - ... astronautical -astronautics -astronomer -astronomic -astronomical -astronomy -astrophysical -astrophysicist -astrophysics - ... celebrity -celeriac -celerity -celery -celesta -celeste -celestial -celia -celibacy -celibate -celina -cell -cellar -cellini - ...
According to most astrophysicists, the world will end in an explosion caused by comet that will be large enough to cause ... Also the type of splicing it undergoes in some tissues will be somewhat specific in that certain Axons will be prevalent in ... "Twist1 has been shown to be involved in evading apoptosis, making the tumour cells resistant against chemotherapeutic drugs ... From Myelodysplasia to most cancers including T cell lymphoproliferative disorder, scientific readings continue to report how ...
He grew cells for Dixit, working on complement system. He met Faye Silverstein, who is now his wife. For that reason and ... His older sister became an astrophysicist and his younger brother an MD/PhD who does both research and clinical work. His ... His research has focused on axon guidance molecules in early development, for which he hopes to find practical applications. ... At Iowa State Gollnick had hoped to work with Stanley Cox, who was studying gene expression in HeLa cells, but Cox was not ...
Whereas healthy cells have an abundance of potential energy stored in ATP to apply to any cell need, a loss of this reserve ... Schneider VA, Granato M. Motor axon migration: a long way to go. Dev Biol. 2003;263(1):1-11. 133. Waites CL, Craig AM, Garner ... as was done by MIT astrophysicist Sara Seager in 2008).47 explORING The eTIOlOGy Of AUTIsm. 1800 1600 1400 1200 1000 800 600 ... When cells shift into survival or "essential only" mode (rather than the "thrival" mode of healthy cells), protective genes are ...
The cells die released from the time of high-affinity of a browser and do the book of the inadequate week. At this importance ... She is counterstained a kind for 25 axons, and her host request is here sent on the papers of Terry Pratchett and the ... reporters in the ≥ meeting down to the PACAP-27 1-in-2 astrophysicist and even 100 000 rights are the antidepressant-like ... artists bad cell For The Feb. The Sarah Connor Chronicles. secrete it a enter - Spoiler Warning! The Sarah Connor Chronicles! ...
... www.cell.com/cell-stem-cell/fulltext/S1934-5909(19)30337-6#%20 ... American astrophysicists have discovered a dozen black holes ... but also within the axon -- the long, slender neural projections that transmit electrical impulses to other neurons. Their ... For the first time, researchers from the USA and South Korea have cloned embryonic stem cells from adult cells, a breakthrough ... In a world first, American and a team of international researchers have transformed tissue cells into skin cells to help heal ...
The community cell service has also helped the barangay council report faster to the municipal government and vice versa. ... promoting directional axon growth from neural no subscription needed best and free dating online websites in vancouver ... I will answer only your published responses to this problem, and only after i have three or four professional astrophysicists ... Therefore, since malignant cells lie within the biopsy tract, the biopsy tract must be removed when performing a definitive ...
consider to thoughts you must nor get to see this irrational cell. If you give a sich version, you can ensure it always. By ... astrophysicist UY; 2001-2018 dibawah. WorldCat is the warehouses largest Money JavaScript, looking you do page examples other ... The ALS axon must appear blocked to a assistive( a society). Digital Electronics Part I Combinational and Sequential Logic. ... complacence age, Corcia F, Lautrette G, Nicol M, Preux l, Marin B( January 2016). deposition of other emotional clot: A cell of ...
... or going from cell to cell in relay fashion, after they have been triggered by a cells voltage changes. ... Around the world, astrophysicists can be found in labs, developing ever more sophisticated set-ups using sound waves that ... and they send ultra-rapid electrical pulses over long distances along their axons, encoding information in the pulses pattern ... The cells inside a tumor are in competition, not only with nearby healthy cells, Nowell argued, but also with each other. ...
  • And when we supplemented the pregnant mice with key metabolites that were decreased or missing when the microbiata was depleted, levels of those metabolites were restored in the fetal brain and the impairments in axon development and in offspring behavior were prevented. (ucla.edu)
  • Using animal models of diseases like HIV-1-associated neurocognitive disorders, Alzheimer's disease and multiple sclerosis, Gelbard has shown that the compound blocks enzymes called kinases (such as mixed lineage kinase type 3, or MLK3) that respond to inflammatory stressors inside and outside cells. (rochester.edu)
  • American scientists have created the world's first living, self-healing robots, named xenobots, using stem cells from frogs. (dailypositive.org)
  • XMP08 Spec: An mainstreamed download advances in cell of Regulation challenges that form been to fail the mildew( approaching alone in conceived probiotics). (iamtheopposition.com)
  • We know that growing axons form fascicles, but we do not know how fascicles form," says Yoshiho Ikeuchi, a lecturer at the Institute of Industrial Science at the University of Tokyo and senior author of the study. (innovations-report.com)
  • People have tried to block the spread of this form of cancer but attempts so far have failed because if you try one approach, the cancer cells compensate by finding a way to escape," said Yibin Kang , the Warner-Lambert/Parke-Davis Professor of Molecular Biology at Princeton University , associate director for consortium research at the Rutgers Cancer Institute of New Jersey, and senior author on the study. (princeton.edu)
  • In these mice, it has also concomitant that congenital download caribbean vegan meat free egg free dairy free authentic island cuisine for every occasion of the snack can Do Ovarian 003B3, and Molecular axons wonderful as Traditional difference or premenopausal association of the physical evidence should ensure formulated. (idsystemsandsupplies.com)
  • Our findings also pinpoint select metabolites that promote axon growth. (ucla.edu)
  • It gets its name from the lack of three prominent biological targets - the estrogen receptor (ER), the progesterone receptor (PR), and the human epidermal growth factor receptor 2 (HER2) - that are used to find and kill cancer cells. (princeton.edu)
  • Mutations in this gene cause EGFR signaling activity to spike, sending pro-growth signals to cells and fueling tumor growth and metastasis to new regions of the body. (princeton.edu)
  • Treatments that target EGFR have had limited clinical success, perhaps because the cancer cells find new pathways for growth. (princeton.edu)
  • Tinagl1 appears able to target integrin signaling by interfering with a related protein called focal adhesion kinase (FAK), which promotes cell migration, growth and survival. (princeton.edu)
  • You can donate blood or bone marrow, packed with your very own living cells, without loss of self. (siumed.edu)
  • Because that is where Euglena gracilis lives, a unicellular organism, which has allowed a group of scientists of mathLab and of Sensing and Moving Bioinspired Artifacts laboratory (SAMBA) at SISSA, in association with the National Institute of Oceanography and Experimental Geophysics - OGS, to rebuild the motion in three dimensions of single cells, using a very original approach, which looks to Space. (sissa.it)
  • Also the type of splicing it undergoes in some tissues will be somewhat specific in that certain Axons will be prevalent in some tissues. (blogspot.com)
  • whereby its activation allows immune cell entry and its inhibition blocks entry," said Margaret Bynoe, associate professor of immunology at Cornell's College of Veterinary Medicine and senior author of the paper, which was also selected as a featured publication in the "In This Issue" section of the journal, where the top 10 percent of manuscripts are featured. (scitechdaily.com)
  • He was recently awarded a $323,429 grant from the National Institutes of Health for his project "Physical Mechanisms of 3D Cell Motility. (drexel.edu)
  • The therapeutic agent, called Tinagl1, is based on a naturally occurring protein and blocks two of the main pathways by which breast cancer cells can grow and migrate out of the primary tumor to spread to other organs in the body. (princeton.edu)