Nervous system

About: Nervous system is a research topic. Over the lifetime, 16729 publications have been published within this topic receiving 847181 citations.

A nerve growth factor-regulated messenger RNA encodes a new intermediate filament protein.

Abstract: Differential screening of a cDNA library from the PC12 rat pheochromocytoma cell line previously revealed a clone, clone 73, whose corresponding mRNA is induced by nerve growth factor (NGF). Induction parallels NGF-stimulated PC12 differentiation from a chromaffinlike phenotype to a sympathetic neuronlike phenotype. We report that DNA sequence analysis reveals that clone 73 mRNA encodes an intermediate filament (IF) protein whose predicted amino acid sequence is distinct from the known sequences of other members of the IF protein family. The sequence has highest homology with desmin and vimentin and includes the highly conserved central alpha-helical rod domain with the characteristic heptad repeat of hydrophobic residues, but has lower homology in the amino-terminal head and carboxyl-terminal tail domains. The head domain contains a large number of serine residues which are potential phosphorylation sites. The expression of clone 73 in vivo in the nervous system of the adult rat was investigated by in situ hybridization of clone 73 probes to tissue sections. The mRNA is expressed at high levels in ganglia of the peripheral nervous system, including the superior cervical ganglion (sympathetic), ciliary ganglion (parasympathetic), and dorsal root ganglion (sensory). In the central nervous system, motor nuclei of cranial nerves III, IV, V, VI, VII, X, and XII as well as ventral horn motor neurons and a restricted set of other central nervous system nuclei express the clone 73 mRNA. Tissues apart from those of the nervous system did not in general express the mRNA, with only very low levels detected in adrenal gland. We discuss the implications of these results for the mechanism of NGF-induced PC12 cell differentiation, the pathways of neuronal development in vivo, and the possible function of the clone 73 IF protein and its relationship to other IF proteins.

Anatomy and development of the nervous system of Nematostella vectensis, an anthozoan cnidarian.

Abstract: Nematostella vectensis, an anthozoan cnidarian, whose genome has been sequenced and is suitable for developmental and ecological studies, has a complex neural morphology that is modified during development from the larval to adult form. N. vectensis' nervous system is a diffuse nerve net with both ectodermal sensory and effector cells and endodermal multipolar ganglion cells. This nerve net consists of several distinct neural territories along the oral-aboral axis including the pharyngeal and oral nerve rings, and the larval apical tuft. These neuralized regions correspond to expression of conserved bilaterian neural developmental regulatory genes including homeodomain transcription factors and NCAMs. Early neurons and stem cell populations identified with NvMsi, NvELAV, and NvGCM, indicate that neural differentiation occurs throughout the animal and initiates prior to the conclusion of gastrulation. Neural specification in N. vectensis appears to occur through an independent mechanism from that in the classical cnidarian model Hydra.

A glia-derived signal regulating neuronal differentiation.

Abstract: Astrocytes are present in large numbers in the nervous system, are associated with synapses, and propagate ionic signals. Astrocytes influence neuronal physiology by responding to and releasing neurotransmitters, but the mechanisms that establish the close interaction between these cells are not defined. Here we use hippocampal neurons in culture to demonstrate that vasoactive intestinal polypeptide (VIP) promotes neuronal differentiation through activity-dependent neurotrophic factor (ADNF), a protein secreted by VIP-stimulated astroglia. ADNF is produced by glial cells and acts directly on neurons to promote glutamate responses and morphological development. ADNF causes secretion of neurotrophin 3 (NT-3), and both proteins regulate NMDA receptor subunit 2A (NR2A) and NR2B. These data suggest that the VIP-ADNF-NT-3 neuronal-glial pathway regulates glutamate responses from an early stage in the synaptic development of excitatory neurons and may also contribute to the known effects of VIP on learning and behavior in the adult nervous system.

Presynaptic hyperpolarization: a role for fine afferent fibres

Abstract: Steady arrival of cutaneous impulses at spinal cord results in steady depolarization of passive afferent terminals

N-acetyl-L-aspartic acid content of human neural tumours and bovine peripheral nervous tissues.

Abstract: — Abstract-Tumors of the human nervous system were utilized to investigate the cellular distribution of N-acetyl-L-aspartic acid (NAA). Astroglial tumours contained about 0.144 μmol/g. Oligodendrogliomas and medulloblastomas contained somewhat larger amounts. However, the level of NAA in all gliomas studied was less than that of normal human white matter. NAA was undetectable in meningiomas and acoustic neurinomas. If these results may be taken as representative of normal tissue, they imply a predominantly neuronal localization for NAA. Substantial amounts of NAA were found in peripheral nervous tissues and retina. Neurons seem to vary widely in NAA content.