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)

Vasoactive intestinal polypeptide (VIP) immunoreactive (IR) neurons in the rabbit retina constitute a population of wide-field amacrine cells. To better define this cell population, we examined the coexpression of VIP with other putative retinal transmitters or their biosynthetic enzymes, including gamma-aminobutryic acid (GABA), tyrosine hydroxylase (TH), and somatostatin (SRIF). Colchicine-treated retinas were immersion fixed in 4% paraformaldehyde. The retinas were cut either perpendicular or parallel to the vitreal surface and processed by double-label immunofluorescence techniques using antibodies directed to VIP, GABA, TH, and SRIF. The immunoreactive staining patterns obtained with these antibodies were the same as those described in previous studies. GABA-IR neurons were localized to the proximal inner nuclear layer (INL) and ganglion cell layer (GCL) and processes were distributed throughout the inner plexiform layer (IPL). TH- and SRIF-IR neurons were sparsely distributed to the proximal INL and GCL, respectively. TH-IR processes ramified in laminae 1, 3, and 5, and SRIF-IR processes in laminae 1 and 5 of the IPL. Colocalization experiments showed that all VIP-IR neurons contain GABA immunoreactivity. In contrast, colocalization of VIP and TH or SRIF immunoreactivities was never observed. These results demonstrate that VIP-IR wide-field amacrines of the rabbit retina make up a neurochemically and morphologically distinct subpopulation of the GABA-IR amacrine cell population. Furthermore, VIP-IR amacrine cells constitute a distinct group with respect to the TH- and SRIF-IR amacrine cells.
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PMID:Colocalization of vasoactive intestinal polypeptide and GABA immunoreactivities in a population of wide-field amacrine cells in the rabbit retina. 134 29

The aim of this study was to localize cells immunoreactive for glutamate decarboxylase (GAD), the enzyme of GABA synthesis, in pyloric and oxyntic regions of the rat stomach as well as in the rat and mouse pancreas. GAD immunocytochemistry was carried out on polyethylene glycol or cryostat sections of alkaline paraformaldehyde fixed tissue, with simultaneous immunolabelling of various gastro-pancreatic hormones for topographical comparison. In the rat stomach, nerve fibers displaying intense GAD-like immunoreactivity were seen in the myenteric plexus, the circular muscular layer, the submucosa and the lamina propria of the mucosa. But, they were absent from the submucous plexus. Colchicine treatment of the rats allowed to detect some labelled perikarya in the myenteric plexus suggesting that the GABAergic innervation is at least partly intrinsic to the stomach. In the oxyntic and pyloric mucosa, endocrine cells appeared immunostained for GAD. However, the nature of their hormones remained unknown since double immunodetections revealed that they were immunoreactive neither for gastrin nor for somatostatin. In the rat and mouse pancreas, GAD-like immunoreactivity was found in islet cells which corresponded only to insulin-secreting cells. Somatostatin-, glucagon- and pancreatic polypeptide-immunopositive cells were devoid of GAD immunolabelling. No GAD-like immunoreactivity was detected in the exocrine tissue and innervation. These results strenghten the hypothesis that GABA is not only a neurotransmitter in the stomach but that it could also be an endocrine or paracrine factor in the stomach and pancreas.
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PMID:Localization of GAD-like immunoreactivity in the pancreas and stomach of the rat and mouse. 178 8

The coexistence of immunoreactivity to the peptides substance P, bombesin, calcitonin gene-related peptide and somatostatin has been determined in single, lumbar and sacral dorsal root ganglion cells in the cat. Colchicine pretreated L7 and S1 dorsal root ganglia were embedded in wax and cut into 5 microns sections. Groups of four, serially adjacent sections were reacted with antisera to one of four peptides using avidin-biotin immunocytochemistry. It was thus possible to determine the coincidence of the four peptides in single cell bodies by examining the immunoreactivity in a ganglion cell in one section and then locating the same cell in three adjacent sections. As a comparison, this procedure was repeated on a different population of ganglion cells using antiserum to substance P, bombesin and calcitonin gene-related peptide only. The results indicate that different combinations of three or four peptides may occur in single, small diameter sensory neurons in the cat. It would appear that immunoreactivity to bombesin and/or calcitonin gene-related peptide coexists with immunoreactivity to substance P in some dorsal root ganglion cells. However, immunoreactivity to each of these peptides was also found to occur alone in single cells. Immunoreactivity to calcitonin gene-related peptide but not to the other three peptides was found to occur in some medium-sized cell bodies (up to 70 microns). Somatostatin-like immunoreactivity was found to have a high level of coexistence with substance P-like immunoreactivity in cells which contained immunoreactivity to these two peptides only. Immunoreactivity to all the four peptides tested was found to occur in 18-26% of ganglion cells which contained at least one peptide.
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PMID:The coexistence of neuropeptides in feline sensory neurons. 247 76

In this study, we have correlated the translocation of somatostatin (SRIF) receptors from the cell interior to the plasma membrane with the ability of SRIF to inhibit insulin release. Islets were perifused with glucose (30, 100, 165, 200, or 300 mg/dl) in the presence of sodium isethionate. Sodium isethionate inhibits insulin release, but not the recruitment of SRIF receptors. Thus, the recruitment of SRIF receptors to the surface membrane continued without the lysis of secretion vesicles. SRIF binding rose from 3.75 +/- 0.16 to 6.46 +/- 0.28 fmol/10 islets as glucose concentration increased. Sodium isethionate was then removed, islets perifused with low glucose (30 mg/dl), and challenged with 400 microM isobutylmethylxanthine (IBMX) with or without SRIF (5 micrograms/ml). In the islets perifused with high glucose concentration, IBMX lysed a greater number of vesicles and caused enhanced release of insulin. The greater the number of secretion vesicles marginated to the plasma membrane by glucose, the greater the response to IBMX. Colchicine (1 mM) prevented secretion vesicle migration and this potentiation effect of higher concentrations of glucose was eliminated. In experiments with IBMX and SRIF, the degree of inhibition of IBMX-induced insulin release by SRIF was proportional to the magnitude of SRIF binding to these islets. SRIF inhibited insulin release by 20 microU/100 islets initially perifused with low glucose (30 mg/dl) and by 875 microU/100 islets perifused with high glucose (300 mg/dl). The maximal effect of SRIF was observed when its binding reached a level of 5.4 fmol/10 islets. We conclude that inhibition of insulin release by SRIF is proportional to the SRIF receptor concentration, and that translocation of SRIF receptors during exocytosis plays an important role in paracrine regulation of insulin secretion by rendering the islets more sensitive to SRIF.
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PMID:A unique control mechanism in the regulation of insulin secretion. Secretagogue-induced somatostatin receptor recruitment. 258 96

Using the iodinated luteinizing-hormone-releasing hormone analogue [D-Ala6, N alpha MeLeu7, Pro9 NEt]-luteinizing-hormone-releasing hormone as radioligand, specific binding sites have been visualized in the rat both in the pituitary and the hippocampal formation of the brain. In the hippocampus, the CA1, CA2 and particularly CA3 regions were heavily labelled. These hippocampal sites have a pharmacological specificity resembling that of luteinizing-hormone-releasing hormone receptors in pituitary homogenates and could therefore represent true luteinizing-hormone-releasing hormone receptors. The luteinizing-hormone-releasing hormone superagonist [D-Ala6, Pro9 NEt]-luteinizing-hormone-releasing hormone and the potent antagonist [D-pGlu1, D-Phe2, D-Trp3,6]-luteinizing-hormone-releasing hormone were highly potent in displacing the iodinated luteinizing-hormone-releasing hormone analogue. The weak agonist [Gln8]-luteinizing-hormone-releasing hormone, however, was at least two orders of magnitude less potent. Somatostatin was inactive. Hippocampal luteinizing-hormone-releasing hormone receptors were species-specific, being present in the rat but not in the mouse, guinea-pig, hamster, rabbit and human brains. In order to identify the cellular location of these hippocampal receptors, various lesions were performed. Electrolytic lesions of the septal afferents did not reveal any receptor density change. Colchicine as well as kainic acid injections did, however, reduce considerably the number of hippocampal receptors. Interestingly, in the electrolytically and kainic-acid-lesioned animals, the appearance of non-displaceable luteinizing-hormone-releasing hormone binding sites within a well-defined area corresponding to the lesioned, gliosis-rich area was observed. The present results suggest the presence of pharmacologically specific, species-dependent, luteinizing-hormone-releasing hormone receptors located, at least partly, on intrinsic hippocampal neurons, in particular granule and pyramidal cells.
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PMID:Specific luteinizing-hormone-releasing hormone receptor binding sites in hippocampus and pituitary: an autoradiographical study. 281 69

The possibility that antral somatostatin cells have a self-replicating activity has been studied in three species of rodents: mice, rats and guinea-pigs, after a flash tritiated thymidine injection. The immunocytochemical staining of somatostatin cells, using specific antiserum, was combined with radioautographic procedures. The labelling index for somatostatin cells--and for gastrin cells identified on serial sections--was established after counting a large number of cells at the optical microscope level, on parallel tissue strips removed throughout the entire antrum. A significant percentage of the somatostatin cell population synthesized DNA. Values were similar for the three species of rodents ranging from 0.8 to 1.1%, that is slightly higher than the percentage of labelled gastrin cells, which was 0.67-0.7%. After a 36-hr continuous infusion of radioactive precursor in one rat, the labelling index observed remained low; 2.33% for somatostatin cells and 1.68% for gastrin cells. Colchicine injection in mice allowed the observation of mitotic figures in well differentiated somatostatin cells. Four hours after that injection, the mitotic index was estimated roughly at 0.3%. Thus, evidence has been presented that in rodents a fraction of the antral somatostatin cell population is capable of dividing, similar to the situation in gastrin cells.
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PMID:Self-replication of somatostatin cells in the antral mucosa of rodents. 612 62

The indirect immunofluorescence technique was used to localize substance P, somatostatin, methionine--enkephalin, neurotensin, and oxytocin in the dorsal horn of the rat spinal cord. The unique distribution of each peptide is described and the relative amount of each peptide in laminae I--III of the dorsal horn and the dorsal part of the lateral funniculus qualitatively assessed. Colchicine treatment and dorsal rhizotomy were used to determine, in part, the origin of immunoreactive fibers and terminals observed in the dorsal horn.
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PMID:Immunohistochemical studies of peptidergic neurons in the dorsal horn of the spinal cord. 615 31

Postprandial elevation of 5-phosphoribosyl 1-diphosphate (PPRibP) concentration in the mouse liver (Lalanne, M. and Henderson, J.F. (1975) Can. J. Biochem. 53,394-399) was further studied regarding the effects of protein intake and the underlying mechanisms. The extent and duration of the increase depended on the quantity and quality of proteins ingested. The order of effectiveness of various diets was as follows: 60% casein greater than 20% egg albumin greater than 20% casein greater than 20% gelatin = 20% gluten greater than 20% zein greater than 0% casein. Hepatic purine and pyrimidine biosyntheses de novo, as measured by labelled tracer incorporation, increased with increasing protein intake. Nicotinic acid incorporation into NAD increased equally, whether casein-containing or casein-free diets were given. Therefore, the increase of PPRibP level may be brought about by increase in its synthesis. Administration of glucagon or epinephrine similarly elevated the hepatic level of PPRibP. Somatostatin, known to inhibit secretion of pancreatic hormones, suppressed the casein-diet-dependent PPRibP level increase. Colchicine markedly inhibited the casein-diet- and glucagon-dependent responses, but not the epinephrine effect. It is likely that glucagon is a major factor in mediation of the protein-diet-dependent PPRibP level increase and that the cytoskeleton is involved in the glucagon-mediated response.
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PMID:Protein-diet-induced elevation of 5-phosphoribosyl 1-diphosphate concentrations in mouse liver associated with increased syntheses of various nucleotides and the possible involvement of glucagon. 620 43

Glucose stimulation of [32P]-prelabelled pancreatic islets induced an increased incorporation of radioactivity into phosphatidylinositol. Glucagon and agents that increases cAMP in the islet did not affect phosphatidylinositol turnover, in spite of increased release of insulin. Furthermore, the potent inhibitor of insulin release, somatostatin did not alter phospholipid metabolism. Colchicine inhibited glucose-stimulated turnover of phosphatidylinositol as well as insulin release. These results may suggest that: (1) cAMP and phosphatidylinositol turnover are involved in different transmembrane control system for regulating insulin release; and (2) the function of microtubules modulate phospholipid metabolism.
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PMID:Effects of insulin secretagogues and inhibitors on phospholipid metabolism in Langerhans' islets of rat pancreas. 630 18

The proportion of somatostatin-containing dorsal root ganglion cells innervating the knee joint of the cat via the medial articular nerve was determined by using retrograde labeling with fast blue and immunohistochemistry. Immunoreactivity was found in 8.6% of labeled cell bodies. In colchicine-treated ganglia, the proportion increased to 16.8%. Only small and intermediate-sized perikarya showed somatostatin-like immunoreactivity, indicating that this neuropeptide is synthesized predominantly in primary afferent units with unmyelinated sensory axons but may also be present in primary afferents with thinly myelinated sensory fibers. Colchicine treatment had no influence on the cell size distribution. Colocalization of somatostatin with substance P was determined by comparing the proportions of immunopositive dorsal root ganglion cells after incubation with antibodies against substance P or somatostatin or with a mixture of both. Substance P-like immunoreactivity was found in 18.1% (untreated ganglia) and 19.6% (colchicine treated ganglia) of the labeled neurons. After incubation with a mixed antibody solution, 18.2% of joint afferents in untreated and 19.9% of the cells in colchicine-treated ganglia were immunopositive. Comparing this result with the results obtained using somatostatin and substance P antibodies alone, one can calculate that both neuropeptides are colocalized in about 17% of the cat's knee joint afferents. About 3% of the neurons contain only substance P, whereas almost none of the neurons contain only somatostatin. Based on this fact, one can assume that both neuropeptides are coreleased in peripheral tissue as well as in the central nervous system.
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PMID:Somatostatin-like immunoreactivity in primary afferents of the medial articular nerve and colocalization with substance P in the cat. 754 5


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