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Nervous system
About: Nervous system is a research topic. Over the lifetime, 16729 publications have been published within this topic receiving 847181 citations.
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TL;DR: The present results are consistent with the hypothesis that the PDFMe neurons are circadian pacemaker neurons that may control rhythmic processes in larvae, pupae, and adults.
Abstract: An antiserum against the crustacean pigment-dispersing hormone (PDH) was used to identify PDH-immunoreactive neurons in the developing nervous systems of wild type Drosophila melanogaster and the brain mutant disconnected. Particular attention was paid to a group of PDH-immunoreactive neurons at the anterior margin of the medulla—the pigment-dispersing factor-containing neurons close to the medulla (PDFMe neurons)—that seem to be involved in the control of adult circadian rhythmicity. In adults, this group consists of four to six neurons with large somata (large PDFMe neurons) and of four neurons with small somata (small PDFMe neurons). Both subgroups were usually absent in adults of behaviorally arrhythmic mutants of disconnected. In the wild type, PDH immunoreactivity was seen first in the small PDFMe neurons of 4 hour old first-instar larvae. The small PDFMe neurons were found to persist unchanged into adulthood, whereas the large ones seemed to develop halfway through metamorphosis. Beside the PDFMe neurons, three other clusters of PDH-immunoreactive neurons were stained in the developing nervous systems of Drosophila and are described in detail. Two of them were located in the brain, and the third was located in the abdominal neuromeres of the thoracic nervous system. In the mutant disconnected, the larval and the adult set of PDFMe neurons were absent. The other clusters of PDH-immunoreactive neurons seemed to develop normally. The present results are consistent with the hypothesis that the PDFMe neurons are circadian pacemaker neurons that may control rhythmic processes in larvae, pupae, and adults. J. Comp. Neurol. 380:335–354, 1997. © 1997 Wiley-Liss, Inc.
196 citations
TL;DR: Fluorescein- and rhodamine-conjugated dextran-amines are used as axonal tracers in in vitro preparations of the nervous system of the chicken embryo to reveal the dendritic and axonal structure of labelled neurons.
196 citations
TL;DR: A newly discovered bioactive peptide, neuropeptide tyrosine (NPY), has been found in the human cardiac nervous system, and analysis of the peptide by high-performance liquid chromatography demonstrated that it was present in a single molecular form, closely similar or identical to that of the isolated bio active peptide.
196 citations
TL;DR: The results demonstrate that GDNF is likely to be an endogeneous survival factor in the normal mammalian cochlea and it could have application as a pharmacological treatment to prevent secondary auditory nerve degeneration following organ of Corti damage.
196 citations
TL;DR: It is demonstrated that P450c17 is expressed in the nervous system of the developing rodent embryo, suggesting it is a marker for the axonal growth in this region, and that its neurosteroid product may be a signal for targeting cortical axons during embryogenesis.
Abstract: Neurosteroids are steroids that are synthesized de novo in the brain and include some classical (adrenal and gonadal steroids) and some unique brain-specific steroids. Neurosteroids are thought to mediate their action through ion gated channel receptors such as gamma-aminobutyric acid(A) and N-methyl-D-aspartate rather than through classical nuclear steroid hormone receptors. Some enzymes involved in neurosteroidogenesis have been identified as those found in steroidogenic tissues, and some may be unique to the brain. We previously demonstrated that the messenger RNAs (mRNA) for the cholesterol side-chain cleavage enzyme, cytochrome P450scc, and one form of 11 beta-hydroxylase, cytochrome P450c11 beta, are regionally expressed in the adult rat brain. However, cytochrome P450c17, which has 17-hydroxylase and 17,20-lyase activity and is thought to be required for the synthesis of dehydroepiandrosterone, was not detected in any region of the rat brain, even though dehydroepiandrosterone is one of the most abundant neuroactive steroids. We now demonstrate that P450c17 is expressed in the nervous system of the developing rodent embryo. By ribonuclease protection assays, P450c17 mRNA was found in the trunk but not in the head of rat embryos but reverse transcriptase-polymerase chain reaction analysis showed expression of P450c17 mRNA in the head of E15.5 to E19.5 rat embryos. Immunocytochemically detectable P450c17 protein was expressed in the nervous system as early as embryonic day E10.5 in the mouse, mainly in tissue derived from the neural crest. Neuronal cell bodies as well as fibers staining for P450c17 were observed in the central and peripheral nervous systems. The sites of P450c17 expression in the peripheral nervous system suggest it may be involved in a wide variety of sensory-motor functions. In the central nervous system, cell bodies expressing P450c17 are found in the hind brain, in mesencephalic nuclei, and in a region in the location of the locus coeruleus, but in cells distinct from those expressing the dopamine-beta-hydroxylase. Furthermore, its particular location and temporal expression in axons reaching the cortical areas suggest it is a marker for the axonal growth in this region, and that its neurosteroid product may be a signal for targeting cortical axons during embryogenesis.
196 citations