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)

We studied the secretion of somatostatin and HCl and the release of vasoactive intestinal polypeptide (VIP) and gastrin-releasing peptide (GRP) from isolated, vascularly perfused, porcine non-antral stomach. Electric vagus stimulation increased acid secretion and the release of VIP and GRP and inhibited somatostatin secretion as determined in the venous effluent. Atropine abolished the HCl response and reversed the somatostatin inhibition to a three-fold increase, whereas GRP and VIP responses were unchanged. Both intra-arterial carbachol (10(-6) M) and GRP (10(-8) M) increased acid secretion and inhibited somatostatin secretion. VIP (10(-8) M) increased somatostatin secretion and had no effect on acid secretion. By immunohistochemistry, somatostatin was localized to both open-type and closed-type cells equally spread in the various parts of the gastric glands without particular relation to the parietal cells. Numerous GRP- and VIP-immunoreactive nerve fibers were seen between the glands. It is concluded that the fundic and antral secretion of somatostatin, investigated in a previous study, are differently regulated. The relation of fundic somatostatin release to acid secretion seems to be complex.
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PMID:Vagal control of the release of somatostatin, vasoactive intestinal polypeptide, gastrin-releasing peptide, and HCl from porcine non-antral stomach. 135 31

Bilateral electrical lesioning of the hippocampal CA3 region (HCA3-EL) or anterior commissura hippocampi (ACHF-EL) caused marked elevations in plasma basal levels of insulin. 2 weeks later, fasting blood glucose levels were also augmented with decreased glucose tolerance. In contrast, the secretory response of pancreatic B cells to glucose stimulation was markedly enhanced. Following intravenous glucose tolerance test (IVGTT), the relative amounts of glucagon-like and insulin-like immunoreactants were reduced in the pancreatic islets of both HCA3-EL and ACHF-EL rats in comparison with the controls. In the HCA3-EL group, the relative amounts of somatostatin-like immunoreactants and gross numbers of such immunostained cells in islets were also decreased as compared with the control. No difference was seen in pancreatic-polypeptide-like immunoreactivities as assessed by immunohistochemistry plus microphotometry method. The above results suggest strongly that HCA3 and ACHF exert a tonic inhibitory action on the insulin secretion in the rat.
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PMID:[Effects of electrical lesioning of hippocampal CA3 region and anterior commissura hippocampi fornix on plasma insulin level and islet cells in the rat]. 136 Jul 7

Postsynaptic targets of the GABAergic septohippocampal and the serotonergic raphe-hippocampal pathways were studied using anterograde tracing with Phaseolus vulgaris leucoagglutinin combined with pre- and postembedding immunocytochemistry in the rat. Two types of afferents were labeled in the hippocampus and dentate gyrus from the medial septum-diagonal band of Broca complex, one with large diameter varicosities and another with smaller terminals. The former type was shown to be immunoreactive for gamma-aminobutyric acid (GABA), and to innervate predominantly GABA-immunoreactive interneurons. Subsequently, these target interneurons were demonstrated to include all subpopulations of GABAergic cells which could be visualized by antisera against parvalbumin, calbindin D28k, calretinin, cholecystokinin, somatostatin, neuropeptide Y and vasoactive intestinal polypeptide. These types of interneurons have different afferent and efferent connections, and thus participate in different inhibitory processes in the hippocampal formation. The other subcortical pathway, the serotonergic projection from the median raphe nucleus, was also shown to establish synapses predominantly with GABAergic interneurons both in the hippocampus and in the dentate gyrus. In contrast to the septohippocampal projection, this pathway did not innervate all types of GABAergic neurons. They selected a particular subpopulation, i.e. those which contain calbindin D28k, and ignored those which contained parvalbumin or the other neurochemical markers. This suggests a strong functional specialization among local inhibitory circuits, as well as among the subcortical afferents originating in the septum and raphe. These findings suggest that a mechanism by which numerically small afferent pathways may have a profound global effect on the electrical activity of the hippocampal formation is the selective innervation of local interneurons. These GABAergic inhibitory cells, in turn, control the activity of large populations of principal cells. The level of GABAergic inhibition determines the degree of population synchrony and influences N-methyl-D-aspartate receptor-mediated epileptiform burst-firing. Thus, the specific subcortical modulation of hippocampal inhibitory circuits may also have fundamental implications for epileptogenesis.
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PMID:GABAergic septal and serotonergic median raphe afferents preferentially innervate inhibitory interneurons in the hippocampus and dentate gyrus. 136 33

The synaptic associations of neurons in the suprachiasmatic nucleus (SCN) of rats were examined by single immunolabeling for somatostatin (SRIH) and arginine vasopressin (AVP), and double immunolabeling for SRIH plus AVP and vasoactive intestinal polypeptide (VIP) plus AVP. Single immunolabeling showed that SRIH neurons, which displayed some somatic and dendritic spines, formed synaptic contacts with immunonegative and positive axon terminals. AVP neurons also formed synaptic contacts with both immunonegative and positive axon terminals. The immunonegative terminals contained small, spherical clear vesicles or flattened clear vesicles. A few immunopositive AVP fibers made synapses with immunonegative somatic or dendritic spines. Double immunolabeling showed synaptic associations between SRIH axons and AVP cell bodies or dendritic processes, and between AVP axons and the somata or dendrites of SRIH neurons. These findings suggest a reciprocal relation between the two types of neurons. Synaptic contacts between AVP neurons and VIP axon terminals were also demonstrated. Previously, we found synapses between SRIH axons and VIP neurons. Thus SRIH neurons appeared to regulate AVP and VIP neurons. On the basis of these findings, two possible oscillation systems of the SCN are proposed.
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PMID:Neuronal associations in the rat suprachiasmatic nucleus demonstrated by immunoelectron microscopy. 136 97

The times of origin of neurons immunoreactive for somatostatin (SRIF), cholecystokinin (CCK), and vasoactive intestinal polypeptide (VIP) were determined using a combined immunohistochemical-autoradiographic technique. 3H-thymidine (3H-dT) was injected into pregnant rats on gestational day 13 (G13), G15, G17, G19, or G21. Animals were killed on postnatal day 30, that is, after the completion of neuronal migration. Sections of the brain including posterior cingulate cortex (area 29), visual cortex (area 17), and somatosensory cortex (area 3) were processed serially for peptide immunoreactivity and autoradiographically for labeling with 3H-dT. SRIF- and CCK-immunoreactive neurons were cogenerated and comigrated according to an inside-to-outside sequence. Accordingly, neurons in layer VI were born on G13, neurons in intermediate layers were born on G15-G17, and neurons in layer II/III were born on G19-G21. In contrast, VIP-positive neurons did not follow such a sequence. Neurons in all layers of cortex were generated at relatively constant rates between G13 and G21. VIP-immunoreactive neurons were the only known subpopulation of neurons that did not migrate into cortex by an inside-to-outside sequence. Thus, the migration of local circuit neurons to cingulate cortex follows patterns that are similar to those discerned in more differentiated cortical areas.
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PMID:Migration of peptide-immunoreactive local circuit neurons to rat cingulate cortex. 136 6

The central amygdaloid nucleus (ACe) is part of the amygdaloid body, and it has been shown to participate in several stress related reactions. The ACe is densely innervated by tyrosine hydroxylase- (TH), corticotropin releasing factor- (CRF), calcitonin gene-related peptide- (CGRP), neurotensin- (NT), somatostatin- (SOM), enkephalin- (ENK), substance P- (SP), vasoactive intestinal polypeptide- (VIP) and cholecystokinin- (CCK) immunoreactive (IR) nerve terminals. In addition, the ACe contains numerous CRF-, NT-, SOM-, ENK- and SP-IR perikarya. In previous studies it has been shown that stress stimulates the expression of the immediate early gene c-fos in the ACe. The aim of this study was to demonstrate the colocalization of the Fos-IR neurons with the peptide- and TH-IR structures using an immunocytochemical double staining technique. In intact animals the ACe contained only a few Fos-IR neurons. After immobilization stress about 100 Fos-IR neurons were seen per section. They were mainly located in the area, which was enriched by peptide- and TH-IR nerve terminals. The close contacts observed between the Fos-IR neurons and the peptide- and TH-IR nerve endings suggest that the Fos-IR neurons were innervated by these nerve terminals. Furthermore, several NT-, ENK-, SOM- and CRF-IR neurons were observed and the vast majority of these cells exhibited Fos-like immunoreactivity. These results suggest that stress enhances the synaptic activity of the ACe, which stimulates the expression of c-fos. Subsequently, Fos may regulate the expression of the NT, ENK, SOM and CRF genes and thus affect the peptidergic efferents from the ACe.
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PMID:Colocalization of peptide- and tyrosine hydroxylase-like immunoreactivities with Fos-immunoreactive neurons in rat central amygdaloid nucleus after immobilization stress. 136 16

Thymosin alpha 1 (T alpha 1) is a well-characterized immunopotentiating polypeptide originally isolated from calf thymus. We have recently shown in vivo, probable hypothalamic effects of T alpha 1 to decrease the release of the pituitary hormones, TSH, PRL and ACTH from the pituitary gland. Therefore, in the present study we evaluated the effect of the peptide on the release of hypothalamic regulatory hormones: thyrotropin-releasing hormone (TRH) and corticotropin-releasing hormone (CRH), as well as somatostatin (SRIH), from medial basal hypothalamic (MBH) fragments incubated in vitro. After a preliminary time-course study indicated that a 30-min incubation period was optimal, it was used for all the other experiments. At the end of the incubation the tissue was still able to respond to a depolarizing K+ concentration for 15 min by a 4-fold increase of TRH concentration compared to control basal release during the preceding 30 min. T alpha 1 was shown to inhibit the release of TRH and CRH from MBH fragments incubated in vitro with a minimal effective dose (MED) of 10(-11) M. SRIH and CRH release was also inhibited but the MED for these peptides was 10(-9) M. The relative responsiveness to the action of T alpha 1 was TRH greater than CRH, which was greater than SRIH. This correlated with our previous in vivo results for pituitary hormone release, except in the case of SRIH since we previously did not detect any significant effect of the peptide on growth hormone release. Finally, we evaluated the possible involvement of other neurotransmitters in the effect of T alpha 1 on TRH release.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of thymosin alpha 1 on hypothalamic hormone release. 136 97

Secretion systems engineered for the expression of heterologous protein in E. coli provide several advantages for subsequent isolation of purified product. Proteins released from the periplasmic space, which represent a small fraction (i.e., 4-10%) of total cell protein, can readily be separated from other cellular proteins by centrifugation of the remaining cellular debris or cross-flow ultrafiltration. The starting material derived from secretion systems is generally of higher purity than comparable material produced from strains expressing cytoplasmically for systems exhibiting similar expression levels. The available evidence suggests that recombinant proteins derived from the periplasm are generally, but not always (44-46), soluble in a nonaggregated form. Consequently, simple purification protocols can be effectively employed for producing homogeneous product with a high yield. The majority of the secreted recombinant proteins reviewed in this chapter were purified by simple one- or two-step chromatography procedures. High-resolution techniques such as reversed phase HPLC were found necessary only in cases where the secreted polypeptides were contaminated with proteolytic degradation variants, e.g., hirudin (51) and beta-endorphin (22). The fact that a high level of biological activity has been shown to be characteristic of purified recombinant proteins secreted into the periplasmic space suggests the presence of a native conformation stabilized by the expected disulfide linkages. Intramolecular disulfide bonds most probably form either as the polypeptide is translocated through the cytoplasmic membrane into the periplasm or within the periplasmic compartment, which has a higher oxidation potential than that found in the cytoplasm (57). Studies performed with hGH (31) and muIL-2 (35) provide excellent examples of differences observed in protein folding and disulfide bond formation between heterologous proteins expressed in the cytoplasmic and periplasmic compartments. Thus, hGH and muIL-2 extracted from the cytoplasm of E. coli have been characterized as high molecular weight disulfide-bonded oligomers. It is likely that oligomerization occurs as the polypeptides are released from the reducing environment of the cytoplasm. In contrast, secreted hGH and muIL-2 extracted from the periplasm of E. coli by osmotic shock displayed the properties of a property folded native protein with correct disulfide pairing. In the case of muIL-2 only a small residual fraction (approximately 15%) of the purified secreted protein exhibited incomplete oxidation of cysteine (35). Secretion of heterologous proteins into the periplasm prevents their exposure to the action of proteases located in the cytoplasm of E. coli (58). The smaller polypeptides such as somatostatin (59), IGF-1 (46), and hEGF (54) are known to be particularly susceptible to intracellular degradation.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Purification of secreted recombinant proteins from Escherichia coli. 136 83

Specimens of the sigmoid colon were obtained from male and female patients (n = 11) with carcinoma of the colon or rectum and studied immunohistochemically for vasoactive intestinal polypeptide-, somatostatin-, substance P-, neuropeptide Y-, calcitonin gene-related peptide-, met- and leu-enkephalin-, 5-hydroxytryptamine-, and dopamine beta-hydroxylase-containing nerves. In the subdivisions of the submucous plexus (namely, Schabadasch's, Meissner's, and the intermediate plexuses), substance P- and vasoactive intestinal polypeptide-immunoreactive nerve fibers were the most numerous, and equal densities of these nerves were found in all three layers. In contrast, few neuropeptide Y-, met-enkephalin-, leu-enkephalin-, calcitonin gene-related peptide-, somatostatin-, 5-hydroxytryptamine-, and dopamine beta-hydroxylase-immunoreactive nerves were found in these regions. The nerve cell bodies of the submucous plexus contained vasoactive intestinal polypeptide, substance P, leu-enkephalin, somatostatin, and 5-hydroxytryptamine but not neuropeptide Y, met-enkephalin, calcitonin gene-related peptide, and dopamine beta-hydroxylase. Vasoactive intestinal polypeptide-containing nerve cell bodies were found in all three subdivisions. Substance P-, leu-enkephalin-, and somatostatin-immunoreactive nerve cell bodies were found in Schabadasch's plexus and the intermediate region of the submucous plexus, but they were absent from Meissner's plexus; 5-hydroxytryptamine-containing nerve cell bodies were only observed in Schabadasch's plexus. The possible function of the neuropeptide-, dopamine beta-hydroxylase-, and 5-hydroxytryptamine-containing neurons in the different layers of the submucous plexus is discussed.
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PMID:Peptide-containing neurons in different regions of the submucous plexus of human sigmoid colon. 848 77

The central amygdaloid nucleus (ACe) is part of the amygdaloid complex that participates in adrenocorticotrophin secretion, stress-related reactions and behavioral functions. The ACe contains numerous glucocorticoid receptor (GR)-immunoreactive (IR) neurons, and in addition it has been shown to contain several neuropeptide-IR somata and nerve terminals. In order to study the relationship between the GR- and neuropeptide-IR structures we mapped the distribution of GR-like immunoreactivity (LI) in amygdaloid complex and colocalized the neuropeptide- and GR-LIs in the ACe. In the amygdaloid complex the central, medial and cortical nuclei contained a high number of GR-IR neurons, whereas a moderate number of GR-IR neurons were observed in the basolateral and basomedial nuclei. Only a few GR-IR neurons were seen in the lateral nucleus. In the ACe, the majority of corticotrophin-releasing factor (CRF)-, met-enkephalin (met-ENK)-, neurotensin (NT)- and somatostatin (SOM)-IR neurons contained also GR-IR. About half of the substance P (SP)-IR neurons were seen to contain GR-IR, whereas only some of the few vasoactive intestinal polypeptide and cholecystokinin-IR neurons showed GR-LI. Nerve terminals containing calcitonin gene-related peptide and the above mentioned peptides were seen in close contact with the GR-IR neurons. These results suggest that the glucocorticoids may modulate directly the neurotransmitter synthesis of the CRF-, met-ENK, NT-, SOM- and SP-IR cells in the ACe.
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PMID:Colocalization of peptide and glucocorticoid receptor immunoreactivities in rat central amygdaloid nucleus. 137 77


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