Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Somatostatin-like immunoreactive amacrine cells of the chicken retina have been characterized by immunohistochemistry at the light and electron microscope levels. The cell bodies were set back from the junction of the inner nuclear and inner plexiform layers, and prominent fibre plexuses were found in sublaminas 1 and 3-5 of the inner plexiform layer. The cells were distributed across the retinal surface with a centroperipheral gradient of cell density. Locally, the cells were organized in a non-random mosaic. Ultrastructurally, immunohistochemical reaction product was found throughout the cytoplasm of the cell bodies, particularly associated with membranous structures, including the cytoplasmic surfaces of the Golgi apparatus, and within large dense-core vesicles. In dendritic varicosities in the inner plexiform layer, reaction product was associated with the external surfaces of small, clear synaptic vesicles. The synaptic relationships of the somatostatin-immunoreactive terminals in sublamina 1 were distinct from those in sublaminas 3-5. Those in sublamina 1 received input predominantly, possibly exclusively, from bipolar cells. Feedback synapses onto bipolar terminals or to the other amacrine cell process at a synaptic dyad were observed. In sublaminas 3-5, input came predominantly, possibly exclusively, from other, non-immunoreactive amacrine cells, and output was primarily onto other amacrine cells. No synaptic contacts with ganglion cells or with other somatostatin-immunoreactive amacrine cells were identified. Changes in levels of somatostatin-like immunoreactivity in retinas of chicks kept on 12:12 light:dark cycles were detected by radioimmunoassay, and by light and electron microscopic immunohistochemistry. Levels of retinal somatostatin-like immunoreactivity increased in the light and decreased in the dark. The changes appear to be light-driven rather than circadian, since with prolonged exposure to light or dark, the levels of somatostatin-like immunoreactivity continued to increase or decrease until plateaus were reached. The light-driven change in levels of somatostatin-like immunoreactivity may be related to the predominance of bipolar input to the immunoreactive processes in sublamina 1 of the inner plexiform layer. The reduction in peptide levels in the dark may indicate greater release of somatostatin-like immunoreactivity from the amacrine cells in the dark, resulting in an inability of peptide synthesis to keep pace with breakdown. In the light, release of somatostatin-like immunoreactivity may be lower, leading to a net synthesis of peptide.
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PMID:Somatostatin-immunoreactive amacrine cells of chicken retina: retinal mosaic, ultrastructural features, and light-driven variations in peptide metabolism. 287 18

A freeze-drying technique using epoxy-embedded ultrathin serial sections permits critical comparisons of neuropeptides in small fibers and varicosities of the nervous system by video-enhanced, light microscopic immunofluorescence. The desirability of the method was documented by data showing: retention of radioimmunoassayable somatostatin in freeze-substituted blocks of tissue as compared to its loss in tissue dehydrated in an alcohol series; feasibility of OsO4 vapor fixation of freeze-dried tissue and compatibility with neuropeptide immunocytochemistry, and utility of a silicon-intensified-tube video camera for recording low levels of fluorescence from ultrathin sections. Ultrathin serial sections, 150 nm thick, from the inner zone of freeze-dried median eminence of the cat revealed three populations of axons containing various combinations of neurophysin immunoreactivity and enkephalin immunoreactivity. Some elements contained neurophysin immunoreactivity alone, some contained both neurophysin immunoreactivity and enkephalin immunoreactivity, and a few elements contained enkephalin immunoreactivity alone. The adjacent external zone of the median eminence contained immunoreactivity for all three substances, but the structures in this region were too small to permit demonstration of coexistence in 150 nm thick sections.
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PMID:Video-enhanced technique for detecting neurophysin, enkephalin, and somatostatin immunoreactivity in ultrathin sections of cat median eminence. 287 21

Somatostatin-like immunoreactive neurons are present in both the myenteric and the submucous plexuses of the small intestine of the guinea pig. Dense varicosities of immunopositive nerve fibres surround the ganglionic cells, some of which also display somatostatin-like immunoreactivity. Immunoelectron microscopy demonstrated axo-somatic synapse formation between the somatostatin immunoreactive neuronal elements. Nerve lesion experiments using argon laser irradiation showed that most of the somatostatin-like immunoreactive fibres of the myenteric plexus were directed anally, whereas those of the submucous plexus had no directional polarity.
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PMID:Somatostatin neurons in the small intestine of the guinea pig: a light and electron microscopic immunocytochemical study combined with nerve lesion experiments by laser irradiation. 288 Sep 33

The distribution and fine structure of somatostatin-like immunoreactive neurons in rat hippocampus and gyrus dentatus were investigated by light and electron microscopic immunocytochemistry. Somatostatin-like immunoreactive neuronal perikarya and fibers could be visualized by using modified PAP immunocytochemistry. Immunoreactive neurons were selectively localized in the stratum orience of the hippocampus and hilar region of the gyrus dentatus, however, immunoreactive neurons were also sparsely observed throughout hippocampal formation. Somatostatin-like immunoreactive varicosities were abundantly distributed in the stratum pyramidale and some of them were considered to terminate on the pyramidal cells. Somatostatin-like immunoreactive neurons in the hippocampal formation generally contained many mitochondria, well-developed rough surfaced endoplasmic reticulum (rER), polysomes and some dense granules. Immunoreactivity was observed especially in the dense granules and membrane of rER. Pre- and post-synaptic elements of somatostatin-like immunoreactive neurons were detected throughout the hippocampal formation.
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PMID:Light and electron microscopic study of somatostatin-like immunoreactive neurons in rat hippocampus. 288 97

Neurotensin- and somatostatin-like immunoreactivities were localized by pre-embedding techniques in retinal whole-mounts and radial sections of a monochromatic glass catfish (Kryptopterus bicirrhis), a dichromatic cichlid species (Aequidens pulcher), and the tetrachromatic roach (Rutilus rutilus). Both neuropeptides were observed in perikarya and processes of amacrine cells. For a precise identification of cell types, tangential and radial views were correlated with Golgi-impregnated material. The dendritic pattern defining the morphological subtype of amacrine cells was determined by the given neuropeptide or by the species-specific degrees of complexity of retinal structure and function. Neurotensin-like immunoreactivity was localized in amacrine cells of intermediate size, radial symmetry and dendrites with numerous varicosities; they were monostratified in sublayer 3 of the inner plexiform layer. This cell type was common to all three species. In the mono- and dichromatic retinas, a single type of amacrine cell with somatostatin-like immunoreactivity was found with radially oriented, varicose dendrites in sublayer 5. In the tetrachromatic roach retina, two somatostatin-positive amacrine cell types were found with very different patterns of ramification; furthermore, both of these types occurred in more than one sublayer. Possible functional implications for color vision of neuropeptide-specific amacrine cells with uniform morphology in all three species and those with a more varied morphology in the tetrachromatic roach are discussed.
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PMID:Amacrine cells with neurotensin- and somatostatin-like immunoreactivities in three species of teleosts with different color vision. 288 25

Synaptic organization of the intermediolateral nucleus of the guinea pig thoracic spinal cord was examined with particular focus on monoamine- and peptide-containing nerve terminals. Axon varicosities having flat synaptic vesicles constituted 17% of all axons in the nucleus and formed exclusively symmetric synapses. Enkephalin-, substance P-, somatostatin-, 5-hydroxytryptamine-, and catecholamine-immunoreactive nerve terminals were densely distributed, while neurotensin, vasoactive intestinal polypeptide-, oxytocin-, and cholecystokinin-8-immunoreactive nerves were sparse in the nucleus. Coexistence of 5-hydroxytryptamine and enkephalin was demonstrated, and coexistence of somatostatin and enkephalin as well as somatostatin and 5-hydroxytryptamine in the same axons was also shown by serial semithin sections. Catecholamine axons labelled by 5-hydroxydopamine formed axodendritic and axosomatic synapses and made direct synaptic contacts on the preganglionic sympathetic neurons identified by retrograde transport of horseradish peroxidase. Direct synaptic contacts from enkephalin- and substance P-immunoreactive axons to preganglionic sympathetic neurons were also revealed. Enkephalin-, substance P-, and 5-hydroxytryptamine-immunoreactive axons formed axodendritic and axosomatic synapses. Catecholamine axon varicosities constituted 19% of all axon varicosities in the nucleus and 30% of them showed synaptic specializations in a sectional plane. Axon varicosities immunoreactive to enkephalin, 5-hydroxytryptamine, and substance P constituted approximately 35, 19, and 13% of all axon varicosities, respectively, while those with synaptic contacts made up 27, 30, and 26%, respectively, in a sectional plane. Enkephalin-, 5-hydroxytryptamine-, and noradrenaline-immunoreactive axons showed mainly symmetric synaptic contacts.
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PMID:Synaptic structure of the monoamine and peptide nerve terminals in the intermediolateral nucleus of the guinea pig thoracic spinal cord. 288 97

Transmural oesophageal variceal pressure was determined by direct puncture of the varices in 27 patients with liver cirrhosis and oesophageal varices. Variceal pressure was not influenced three to six minutes after somatostatin bolus administration and slightly increased during somatostatin infusion. Thus, potential haemostatic benefits of somatostatin cannot be explained by pressure reductions in the varices.
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PMID:Somatostatin does not reduce oesophageal variceal pressure in liver cirrhotics. 289 36

In this study we examined the hypothesis that the intermediolateral cell column (IML) of the thoracic spinal cord, the nucleus from which preganglionic sympathetic neurons originate, provides an anatomical substrate through which selective regulation of sympathetic nervous system targets is accomplished. Preganglionic sympathetic neurons of rats were retrogradely labeled by the simultaneous exposure of the cervical sympathetic trunk (CST) and the adrenal medulla to Fluoro-Gold and True blue, contrasting fluorescent dyes. Retrograde labeling from these sites revealed 2 populations of sympathetic preganglionic neurons in IML whose distribution overlapped between segments T1 and T4. In regions where these 2 groups of retrogradely labeled neurons overlapped, sympathoadrenal preganglionic (SAP) neurons occupied the most lateral aspect of the nucleus. It was also determined whether individual retrogradely labeled neurons within these two groups sent axon collaterals to both the CST and adrenal medulla. Diamidino yellow, a fluorescent retrograde tracer dye that labels only nuclei, was substituted for Fluoro-Gold and used in combination with True blue to simultaneously label preganglionic sympathetic neurons projecting to either the CST or adrenal medulla. No double-labeled cell bodies were observed in spinal cords of rats treated in this manner. Thus it appeared that the efferent projections of these 2 cell populations in IML were target-specific. Immunohistochemical analysis of the relationship between nerve fibers in the IML and preganglionic sympathetic neurons was also undertaken in an attempt to classify further these 2 populations of sympathetic preganglionic neurons. Equal proportions of identified CST and SAP neurons appeared to be apposed by varicosities immunoreactive for either somatostatin or serotonin. On the other hand, when the comparison was based on whether oxytocin-immunoreactive varicosities appeared to appose these 2 populations of retrogradely labeled sympathetic neurons, a highly significant difference was revealed. That is, oxytocin-immunoreactive fibers and terminals appeared to avoid SAP neurons. Thus these data support the hypothesis that an anatomical substrate exists in spinal cord IML whereby selective regulation of sympathetic nervous system targets may be mediated. Moreover, the lack of oxytocin-immunoreactive varicosities apposing SAP neurons in IML suggests that if the paraventricular nucleus innervates SAP neurons in IML, it does so via a population of neurons that do not use oxytocin as a neurotransmitter.
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PMID:The intermediolateral cell column of the thoracic spinal cord is comprised of target-specific subnuclei: evidence from retrograde transport studies and immunohistochemistry. 289 66

Paraffin sections of cervical and upper thoracic paravertebral ganglia of the cat were investigated by immunohistochemistry using antisera directed against calcitonin gene-related peptide (CGRP). The relationships of CGRP-immunoreactive structures to those exhibiting immunoreactivity to antisera against other regulatory peptides and dopamine-beta-hydroxylase (DBH), respectively, were studied in consecutive sections. Singly scattered CGRP-immunoreactive neuronal perikarya were observed in the superior and middle cervical ganglia as well as in the stellate ganglion. These neurons also displayed immunoreactivity to vasoactive intestinal polypeptide (VIP), and some additionally exhibited faint substance-P immunoreactivity. DBH- and neuropeptide Y-immunoreactive ganglion cells were not identical with CGRP-immunoreactive neuronal cell bodies. According to the immunoreactive properties of varicosities, which abut on CGRP/VIP-immunoreactive perikarya, three types of CGRP/VIP-immunoreactive ganglion cells could be distinguished: (1) CGRP/VIP-immunoreactive neurons being surrounded by somatostatin-immunoreactive nerve fibers, (2) neurons being approached by both DBH- and met-enkephalin-immunoreactive varicosities, and (3) neurons receiving both DBH- and neurotensin-immunoreactive fibers. The stellate and upper thoracic ganglia harbored clusters of intensely VIP-immunoreactive somata, which lacked CGRP-immunoreactivity. Fine somatostatin-immunoreactive and coarse CGRP-immunoreactive fibers were distributed within these clusters, whereas patches of neurotensin-immunoreactive fibers were complementarily arranged. At all segmental levels investigated, a few postganglionic neurons were approached by both CGRP-immunoreactive and substance P-immunoreactive varicosities, but lacked a VIP-immunoreactive innervation. Therefore, CGRP/substance P-immunoreactive fiber baskets appeared rather to be of extraganglionic origin than to emerge from intraganglionic CGRP/VIP/SP neurons.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Neuropeptide distribution in the cervico-thoracic paravertebral ganglia of the cat with particular reference to calcitonin gene-related peptide immunoreactivity. 289 95

Growth hormone (GH) production of the anterior pituitary gland is controlled by inhibiting and releasing hormones that are synthesized in the diencephalon. In order to elucidate the possible interrelationships between somatostatin and growth hormone-releasing factor (GRF) synthesizing neurons at the hypothalamic level, immunocytochemical double labelling studies were performed on sections containing the arcuate nucleus (ARC) of the rat. Somatostatin producing neurons were located in the dorsomedial part of the ARC, while somatostatin immunoreactive (IR) axons were found in the ventro-lateral part of the nucleus, an area containing GRF-synthesizing cells. The use of the dual antigen localization technique revealed the approach and juxtaposition of somatostatin containing axons to dendrites and cell bodies of GRF-synthesizing neurons. At the light microscopic level, several somatostatinergic axon varicosities were clustered around single GRF-synthesizing cells. Ultrastructural analysis of the ventro-lateral part of the ARC showed that (i), somatostatinergic axons established synaptic connections (ii), GRF-producing neurons received axons terminals on their somata and dendrites and (iii), somatostatin-IR axons formed asymmetric synaptic specializations with both dendrites and somata of GRF-synthesizing neurons. These morphological findings indicate that the hormone production and release of hypophysiotrophic GRF-IR neurons can be influenced by the central somatostatin system via direct synaptic mechanisms. The data support the concept, that the interaction of inhibiting and releasing hormones, which determines responses of the pituitary target cells, may take place also at the hypothalamic level.
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PMID:Synaptic communication between somatostatinergic axons and growth hormone-releasing factor (GRF) synthesizing neurons in the arcuate nucleus of the rat. 290 Feb 29


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