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

The effect of the neuropeptide galanin on insulin and somatostatin secretion in the rat was studied under various conditions. In the perfused rat pancreas, insulin secretion stimulated by arginine, but not cholecystokinin-8 (CCK-8) or acetylcholine (ACh) was inhibited by both rat and porcine galanin, whereas ACh-stimulated somatostatin release was inhibited by rat but not porcine galanin. Neither arginine nor CCK-8 significantly altered somatostatin secretion and galanin was without effect under those conditions. Gastric inhibitory polypeptide-stimulated insulin release from cultured mixtures of purified rat beta- and non-beta-cells was inhibited by rat and porcine galanin in a concentration-dependent and equipotent manner. The results suggest that the inhibitory effect of galanin on insulin and somatostatin secretion may be stimulus-specific and species-specific.
 ...
PMID:Stimulus-specific inhibition of insulin release from rat pancreas by both rat and porcine galanin. 128 Jul 55

Huntington's disease is a progressive neurodegenerative disease in which the basal ganglia are preferentially affected. Recent evidence, however, suggests involvement of the cerebral cortex as well, with sparing of neurochemically defined subsets of gamma-aminobutyric acid (GABA)-ergic interneurons. In the present study, we examined changes in concentrations of the amino acid neurotransmitters GABA, glutamate, and aspartate in nine cortical regions from 23 patients with advanced Huntington's disease and 12 control brains. GABA concentrations were significantly increased in eight of the nine regions, consistent with a sparing of GABAergic local circuit neurons in the context of progressive cortical atrophy. Small but significant increases in glutamate were found in six of the nine regions, while aspartate levels were generally unaffected. Striate cortex (Brodmann's area 17) showed the most profound increases in GABA and glutamate. We also investigated the effects of powdering the excitotoxins N-methyl-D-aspartate (NMDA) or kainic acid onto the dura of rats. The resulting lesions were examined at 1 week and 6 months. The NMDA-induced lesions showed striking sparing of parvalbumin-positive neurons (a subset of GABAergic interneurons), and this sparing was reflected in neurochemical measurements of GABA; kainic acid lesions failed to display this selectivity. Somatostatin, cholecystokinin, and vasoactive intestinal polypeptide concentrations were spared by the NMDA-induced lesions, and substance P levels were significantly increased. These results provide evidence that NMDA excitotoxic lesions of cerebral cortex can produce a selective pattern of neuronal damage similar to that which occurs in Huntington's disease.
 ...
PMID:The cortical lesion of Huntington's disease: further neurochemical characterization, and reproduction of some of the histological and neurochemical features by N-methyl-D-aspartate lesions of rat cortex. 128 Sep 37

Pulmonary neuroepithelial endocrine cells have been shown to contain serotonin-immunoreactivity in almost every species studied. Regulatory peptides, of which at least ten have been reported so far, were mostly only demonstrated in a number of the investigated species or in a subpopulation of neuroepithelial endocrine cells. Calcitonin gene-related peptide, calcitonin, bombesin/gastrin-releasing peptide, enkephalin, somatostatin, substance P, cholecystokinin and polypeptide YY were found in normal lung tissues, whereas ACTH and several other bioactive substances should be regarded as ectopic. The human pulmonary neuroepithelial endocrine system seems to harbour the largest spectrum of bioactive mediators. The distribution patterns of bioactive substances in various subpopulations of solitary neuroepithelial endocrine cells or neuroepithelial bodies and in different cells of a single neuroepithelial body reveal a great complexity. Therefore, further research is needed to elucidate the chemical coding of this system.
 ...
PMID:Comparative histological overview of the chemical coding of the pulmonary neuroepithelial endocrine system in health and disease. 128 Sep 75

Biopsies of human cerebral cortex were fixed by immersion and immunostained for the detection of neuropeptides in neuronal cell bodies and axons. Four neuropeptides (neuropeptide Y, somatostatin, , substance P and cholecystokinin) were visualized in a series of adjacent sections. All populations of immunoreactive neurons had a morphology characteristic of interneurons, with variations in dendritic arborizations and laminar distribution. The cholecystokinin-immunoreactive neurons were most numerous in the supragranular layers, whereas neurons containing the other three peptides occurred mainly in infragranular layers, or even in neurons populating the subcortical white matter. Quantitatively, each population of neuropeptide-containing neurons accounted for 1.4-2.5% of the total neuronal population. The distribution of these neurons varied slightly between cytoarchitectonic divisions, with substance P- and somatostatin-immunoreactive neurons dominating in the temporal lobe and cholecystokinin-immunoreactive neurons in the frontal lobe. Neuropeptide Y-immunoreactive neurons dominated in the gray matter of the frontal half of the hemisphere and in the subcortical white matter of the caudal half of the hemisphere. Furthermore, co-existence of neuropeptide Y or substance P immunoreactivity within somatostatin-immunoreactive neurons could be demonstrated using double labeling immunofluorescence techniques. The axonal plexuses immunoreactive for neuropeptide Y, somatostatin, or substance P were distributed in all layers, with a strong predominance of horizontally oriented fibers in layer I, a moderate plexus of randomly oriented fibers in the supra- and infragranular layers, and a slightly weaker innervation of layer IV. Immunoreactive axons formed, in addition, complex terminal arbors, mostly in older subjects, suggesting that they resulted from an as yet undefined aging process. The present study underlines several aspects of the organization of the neuropeptide-containing neurons of the human cerebral cortex, which are of particular interest in the light of the involvement of these neurons in several neurodegenerative diseases.
 ...
PMID:Morphology and distribution of neuropeptide-containing neurons in human cerebral cortex. 128 28

The HCN-1A clonal cell line, derived from the cortical tissue of a patient with unilateral megencephaly, was shown to differentiate into a mature neuronal-like state in the presence of the nerve growth factor, dibutyryl cyclic adenosine, 3',5'-monophosphate and either 1-isobutyl-3-methylxanthine or forskolin. Differentiation was assessed by measuring the percentage of cells that displayed branched, varicose processes that stained for synaptophysin. Treatment of cultures with a cocktail containing forskolin increased immunocytochemical staining for gamma aminobutyric (GABA), neurofilament protein and the nerve growth factor receptor species p75NGFR. Treatment with acetyl-L-carnitine alone had some effects on the cell morphology while acetyl-L-carnitine arginyl amide and nerve growth factor together increased the GABA content. Positive staining levels for the neurotransmitters gamma aminobutyric acid, glutamate, somatostatin, cholecystokinin and vasoactive intestinal polypeptide were measured quantitatively for HCN-1A under basal conditions.
 ...
PMID:Effects of nerve growth factor and acetyl-L-carnitine arginyl amide on the human neuronal line HCN-1A. 128 85

The regulation of histamine release from oxyntic mucosa is complex because of two potential sources of histamine: mast cells and enterochromaffin-like (ECL) cells. A gastrin-responsive histamine pool was identified in the rat oxyntic mucosa two decades ago, but these ECL cells from the rat have not yet been isolated or characterized in vitro. In vivo studies in canine and human mucosa have been more difficult because of the high content of histamine in mast cells. Using enzyme-dispersed canine oxyntic mucosal cells, we have studied regulation of histamine release from a mast cell-depleted fraction prepared by sequential elutriation and density gradient. Histamine-like immunoreactivity was demonstrated, using peroxidase-anti-peroxidase immunohistochemistry. After short-term culture, histamine was released in response to gastrin, cholecystokinin, carbachol, and forskolin. Somatostatin potently and effectively inhibited the response to gastrin. The cultures used for these studies also contained somatostatin cells, and, furthermore, the response to gastrin was enhanced by incubation with monoclonal antibodies to somatostatin. The latter findings suggested that somatostatin was acting in these cultures by a paracrine route. This pattern contrasts with that obtained in previous studies of canine oxyntic mucosal mast cells.
 ...
PMID:Regulation of histamine release from oxyntic mucosa. 128 99

Dogs were given a prostaglandin analogue, misoprostol, at a dose that significantly increases gastrointestinal epithelial cell proliferation. Both basal and postprandial concentrations of gastrin were significantly higher in the misoprostol-treated dogs and more than doubled after the meal in both the controls and in the test group. Plasma enteroglucagon, cholecystokinin, insulin and glucose-dependent insulinotrophic peptide all increased postprandially, with no effect of misoprostol. Tissue concentrations of bombesin, gastrin and somatostatin were unaffected by misoprostol, but the fundic glucagon-like immunoreactivity was significantly increased. Thus high doses of misoprostol have only minor effects on gastrointestinal regulatory peptides, suggesting that the trophic effect of prostaglandins on the intestinal tract may be direct.
 ...
PMID:Plasma and tissue hormones in the dog after administration of the prostaglandin analogue, misoprostol. 128 66

Sympathetic ganglia are innervated by neuropeptide-containing fibers originating from pre- and postganglionic sympathetic neurons, dorsal root ganglion neurons, and in some cases, myenteric neurons. In the present report receptor autoradiography was used to determine whether sympathetic ganglia express receptor binding sites for several of these neuropeptides including bombesin, calcitonin gene-related peptide-alpha, cholecystokinin, galanin, neurokinin A, somatostatin, substance P, and vasoactive intestinal polypeptide. The sympathetic ganglia examined included the rat and rabbit superior cervical ganglia and the rabbit superior mesenteric ganglion. High levels of receptor binding sites for cholecystokinin, galanin, somatostatin, substance P, and vasoactive intestinal polypeptide were observed in all sympathetic ganglia examined, although only discrete neuronal populations within each ganglion appeared to express receptor binding sites for any particular neuropeptide. These data suggest that discrete populations of postganglionic sympathetic neurons may be regulated by neuropeptides released from pre- and postganglionic sympathetic neurons, dorsal root ganglion neurons, and myenteric neurons.
 ...
PMID:Receptor binding sites for cholecystokinin, galanin, somatostatin, substance P and vasoactive intestinal polypeptide in sympathetic ganglia. 131 31

The possible influence of several neuropeptides on muscarinic receptor binding and function in fronto-parietal cortex of young and senescent Fischer 344 rats was examined. Low concentrations (100 nM) of cholecystokinin, neurotensin and vasoactive intestinal polypeptide (VIP), added in vitro, enhanced carbachol-stimulated phosphoinositide metabolism in cortical miniprisms from both young and senescent rats, while somatostatin was ineffective. Interestingly, the VIP receptor antagonist [d-parachloro-Phe6,Leu17[VIP shifted the dose-response curve for carbachol significantly to the right, indicating inhibition of phosphoinositide hydrolysis. No direct actions of neuropeptides on the number or affinity of [3H]l-quinuclidinyl benzilate binding sites nor on agonist conformation states of the muscarinic receptor were noted in cortex from young animals. The neuropeptide modulation of phosphoinositide metabolism was selective for muscarinic systems, as norepinephrine-stimulated phosphoinositide hydrolysis was not altered. Pretreatment with hemicholinium-3, an inhibitor of high-affinity choline uptake, did not prevent the neuropeptide effects, indicating the interaction was probably postsynaptic. It is possible that pharmacologic manipulation of peptidergic processes could improve cholinergic neurotransmission in brain.
 ...
PMID:Neuropeptide modulation of muscarinic receptors and function in cerebral cortex of young and senescent rats. 131 40

Intrahepatic bile duct epithelial cells, or cholangiocytes, contribute to bile secretion in response to hormones, including secretin. However, the mechanism by which secretin stimulates ductular bile flow is unknown. Since recent data in nonhepatic epithelia have suggested a role for exocytosis in fluid secretion, we tested the hypothesis that secretin stimulates exocytosis by isolated cholangiocytes. Cholangiocytes were isolated from normal rat liver by a newly described method employing enzymatic digestion and mechanical disruption followed by immunomagnetic separation using specific monoclonal antibodies, and exocytosis was measured using a fluorescence unquenching assay employing acridine orange. Secretin caused a dose-dependent (10(-12)-10(-7) M) increase in acridine orange fluorescence by acridine orange-loaded cholangiocytes with a peak response at 10 min; the half-maximal concentration of secretin was 7 x 10(-9) M. The secretin effect was inhibited by preincubation of cholangiocytes with colchicine (30% inhibition, p less than 0.05) or trypsin (90% inhibition, p less than 0.001); no inhibition was seen with lumicolchicine and heat-inactivated trypsin. Cholecystokinin, insulin, and somatostatin had no effect on fluorescence of acridine orange-loaded cholangiocytes; secretin had no effect on fluorescence of acridine orange-loaded hepatocytes or hepatic endothelial cells. Exposure of isolated cholangiocytes to secretin at doses that stimulated exocytosis caused a dose-dependent increase in cyclic AMP levels (218% maximal increase, p less than 0.05); moreover, an analogue of cyclic AMP stimulated exocytosis by cholangiocytes. Secretin had no effect on intracellular calcium concentration using Fura-2-loaded cholangiocytes assessed by digitized video microscopy. Our results demonstrate, for the first time, that secretin stimulates exocytosis by rat cholangiocytes. The effect is cell- and hormone-specific, dependent on intact microtubules, on a protein(s) on the external surface of cholangiocytes, and on changes in cellular levels of cyclic AMP. The results are consistent with the hypothesis that secretin-induced changes in bile flow may involve an exocytic process.
 ...
PMID:Secretin stimulates exocytosis in isolated bile duct epithelial cells by a cyclic AMP-mediated mechanism. 132


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>