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)

The effects of a number of peptides which are found in the gastrointestinal tract have been ascertained on the direct current recorded dorsal and ventral root responses of the isolated hemisected toad spinal cord. Motilin, substance P, bombesin, neurotensin, and thyrotropin releasing hormone had potent depolarizing actions on dorsal root terminals and motoneurons. These substances evoked discernable effects at concentrations as low as 10--7 M, or even lower with motilin. The effects of motilin, neurotensin, and thyrotropin-releasing hormone were greatly reduced or abolished by perfusion of the preparation with tetrodotoxin. Adrenocorticotrophic hormone, secretin, and pancreozymin (cholecystokinin) also depolarized dorsal root terminals and motoneurons. The effects of secretin and cholecystokinin were not abolished by tetrodotoxin. Leu- and Met-enkephalin had weak hyperpolarizing actions on the dorsal and ventral root potentials of repetitively stimulated preparations. Gastrin, gastric inhibitory peptide, glucagon, and somatostatin had no apparent effects on the responses of the preparation. Angiotensin and vasopressin both had rather weak depolarizing effects on the dorsal and ventral roots.
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PMID:Actions of various gastrointestinal peptides on the isolated amphibian spinal cord. 11 60

The substances stimulating the release of immunoreactive corticotropin-releasing factor from cultured human placental cells were investigated. Monolayer primary cultures of trophoblast cells from pregnant women at term were used. The immunoreactive corticotropin-releasing factor released in the culture medium eluted from high-performance liquid chromatography with the same retention time as human corticotropin-releasing factor. Norepinephrine and acetylcholine increased immunoreactive corticotropin-releasing factor release into the culture medium in a dose-related manner. Epinephrine was partially active, whereas dopamine and serotonin did not induce significant changes of immunoreactive corticotropin-releasing factor release from placental cultures. Angiotensin II, interleukin-1, oxytocin, and arginine-vasopressin also increased placental immunoreactive corticotropin-releasing factor release in a dose-related manner, whereas other peptides (vasoactive intestinal peptide, substance P, somatostatin, atrial natriuretic factor, interleukin-2) were ineffective. These results showed that several neurotransmitters and peptides stimulate the release of immunoreactive corticotropin-releasing factor from placental cells, suggesting their possible involvement in the physiologic regulation of placental immunoreactive corticotropin-releasing factor release during pregnancy and parturition.
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PMID:Neurotransmitters and peptides modulate the release of immunoreactive corticotropin-releasing factor from cultured human placental cells. 256 97

Receptors sites for angiotensin II and atrial natriuretic factor were concentrated in the zone glomerulosa of the adrenal cortex in the rat, mouse, hamster, rhesus monkey, guinea-pig and the cow. Angiotensin Ii receptor sites were also accumulated in adrenal medullary tissue of the rat, mouse and the hamster. With exception of the cow the zonae fasciculata and reticulata of the adrenal cortex were not labelled with the angiotensin II ligand, but showed a moderate density of atrial natriuretic factor receptor sites in all species except the rhesus monkey. In comparison, somatostatin receptors were even more heterogeneously distributed in all species mentioned above. In the rat, the increased growth of zona glomerulosa cells found after three weeks of sodium deprivation was accompanied by a similar increase in number of receptor sites for angiotensin II, atrial natriuretic factor and somatostatin. This shows that all three peptide receptors are regulated simultaneously by a single metabolic disturbance, suggesting that they might be localized on the same cell type in the adrenal cortex.
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PMID:Distribution and coregulation of three peptide receptors in adrenals. 301 26

Autoradiographic studies reveal densities of binding to somatostatin, neurotensin, mu-opiate, and benzodiazepine receptors in substantia nigra specimens from neurologically normal human brains. Binding to nigral angiotensin converting enzyme is also dense, whereas more modest densities of kappa-opiate, dopamine, and serotonin receptors are noted. In nigral specimens taken from patients with idiopathic Parkinson's disease, substantial reductions in somatostatin, neurotensin, mu-opiate and kappa-opiate receptors contrast with more modest reductions in dopamine and benzodiazepine I receptor subtypes. Angiotensin converting enzyme, serotonin, and benzodiazepine II binding are virtually unaltered. These results underscore the likelihood of strong peptidergic influences on normal and pathologically altered human nigrostriatal circuitry.
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PMID:Parkinson's disease: nigral receptor changes support peptidergic role in nigrostriatal modulation. 301 28

Hypertensin, gastrin-releasing peptide, neuromedin and substance P activated the buccal ganglia in Planorbis corneus and Lymnaea stagnalis, whereas secretin, somatostatin, pancreosimin and octapeptide of cholecystokinin suppressed them. No effect of neurotensin and alitesine were found. The peptides seem to rearrange functioning of buccal nervous network. Application of the peptides induced no pattern of food program.
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PMID:[Effect of neuropeptides on the motor output of the buccal ganglia of freshwater mollusks]. 362 30

The octapeptide angiotensin II is a major regulator of the adrenal glomerulosa zone, acting both as an acute stimulus of aldosterone secretion and as a trophic hormone which increases steroidogenic enzymes and angiotensin II receptors in glomerulosa cells. Angiotensin II also mediates the adrenal effects of altered sodium balance, and is essential for the aldosterone response to sodium restriction. However, the adrenal effects of angiotensin II are attenuated during sodium loading, suggesting that other local or humoral factors modulate its actions on adrenal glomerulosa function. Somatostatin, the somatotropin release inhibiting factor of the hypothalamus, has been shown to inhibit the secretion and action of several pituitary and non-pituitary hormones. Because somatostatin has been found in several non-neural tissues, and seems to act as a local regulator of endocrine function, we have now examined the possibility that it may also modulate the effects of angiotensin II in the adrenal glomerulosa cell. Our studies have shown that low concentrations of somatostatin specificity inhibit the production of angiotensin II-stimulated aldosterone, and that this action is mediated by specific, high-affinity receptors for somatostatin in the zona glomerulosa.
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PMID:Somatostatin modulates effects of angiotensin II in adrenal glomerulosa zone. 611 34

In the neonatal rat spinal cord slice preparation responses of the dorsal horn interneurons to iontophoretic or bath application of methionine-enkephalin (ME), substance P (SP) and somatostatin (SS) were qualitatively similar to those obtained in intact spinal cord. Thus, SP powerfully excited almost all neurons tested (15/16), while ME and SS depressed neuronal discharges in 13/14 and 4/6 units respectively. In some dorsal horn neurons the iontophoretic application of ME caused a marked depression of the SP-induced excitation. Angiotensin II (AgII) had no effect on dorsal horn units (n = 8). In the slices perfused with a Ca2+-free, Mg2+-high Krebs solution the extracellularly recorded effects of ME, SP and SS were not significantly modified, suggesting that the peptides were acting directly on postsynaptic sites. The results also indicate that the in vitro rat spinal cord slice preparation can be successfully utilized for further studies on the cellular mechanisms of actions of neuropeptides, particularly in relation to synaptic transmission processes in the dorsal horn.
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PMID:Neonatal rat spinal cord slice preparation: postsynaptic effects of neuropeptides on dorsal horn neurons. 616 14

There are now about twelve substances, many of them peptides, that are thought to act as neurotransmitters in the enteric nervous system. Most of the studies of peptides have relied on immunochemical methods for their detection. However, difficulties arise in these studies because of the close similarities between peptides. Related peptides can be grouped in several ways according to similarities of origin, function, effects in bioassays and amino acid sequences. Peptides with the same function in different species, and only slight differences in amino acid sequence, have been called isopeptides. Peptide families that have sequences of amino acids in common, but do not necessarily have similar functions are described. In the guinea-pig small intestine, used as a model, the concentrations of fourteen nerve-related peptides and amines are compared. The actual chemical natures of the peptides are discussed. It is concluded that nerves containing authentic leu- and met-enkephelin, somatostatin and substance P are present. VIP in guinea-pig enteric nerves is different from the porcine standard. Peptides similar to authentic CCK8 and amphibian skin bombesin are present. Angiotensin and neurotensin-like peptides shown immunohistochemically are not the authentic peptides. In the longitudinal muscle plus myenteric plexus, most neuropeptide concentrations are in the range of 10-500 pmole/g. The exception is met-enkephalin (1,300 pmole/g). The amine transmitters have considerably higher concentrations, noradrenaline having a concentration of about 3,500 pmole/g and acetylcholine 1-2 x 10(5) pmole/g.
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PMID:Detection and characterisation of neurotransmitters, particularly peptides, in the gastrointestinal tract. 617 12

The role of ACTH-(1-24) on angiotensin II receptors has been studied in bovine adrenal glomerulosa cells in primary culture. Angiotensin II receptors were measured in cells pretreated or not by ACTH-(1-24) on day 4 of culture. ACTH-(1-24) decreased angiotensin II binding sites in a time and a dose-dependent manner. After 24 hours of treatment the minimal effective dose of ACTH-(1-24) was 10(-11)M and the maximal effect was obtained with 10(-8)M. Moreover, ACTH-(1-24) 10(-8)M decreased significantly angiotensin II receptors after 6 hours of treatment. Scatchard plot analysis showed that ACTH-(1-24) treatment did not modify the affinity of angiotensin II receptors (Ka = 0.42 and 0.44 X 10(9)M-1 in control and treated cells respectively) but reduced by about half the number of angiotensin II sites per cell. Like ACTH-(1-24), 8-Bromo-cAMP, forskolin and cholera toxin decreased angiotensin II receptors. Factors such as prolactin, somatostatin, ACTH-(11-24) and dopamine which are bound to adrenal membranes without increasing cAMP production had no effect. In conclusion, these studies in vitro demonstrate for the first time that ACTH decreases angiotensin II receptors by a direct mechanism acting on glomerulosa cells, and they also suggest that this effect could be mediated by cAMP.
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PMID:Adrenocorticotropin regulates angiotensin II receptors in bovine adrenal cells in vitro. 632 3

The present experiments were devoted to analyzing the hypothesis that somatostatin (SS) could modulate glomerular filtration rate by interacting with mesangial cells. Studies were performed in cultured human mesangial cells, passages 3-5. Radioligand experiments demonstrated the presence in the cells of two kinds of receptors, with high (dissociation constant 14 pM. Number of sites: 426 fmol/mg) and low (dissociation constant 56 pM. Number of sites: 20, 111 fmol/mg) affinity. SS prevented in a dose-dependent manner the reduction in planar cell surface area induced by 100 nM Angiotensin II (AII). This effect was not inhibited by the blockade of the vasorelaxing prostaglandins (indomethacin, 10 microM), nitric oxide (L-N-methyl-arginine, 0.2 mM), adenylate cyclase (2,5'-dideoxyadenosine, 0.1 mM), or guanylate cyclase (Methylene blue, 30 microM; LY-83583, 10 microM), but it was potentiated by zaprinast, an inhibitor of the cyclic GMP (cGMP)-specific phosphodiesterase. SS also blocked the increase in myosin light chain phosphorylation induced by AII. SS increased cGMP synthesis by cultured human mesangial cells, an effect that seemed to be dependent on the stimulation of a particulate guanylate cyclase. Preincubation of the cells with pertussis toxin (0.5 microgram/ml) inhibited the effect of SS on the AII-dependent changes in planar cell surface area, as well as the SS-dependent cGMP stimulation. In summary, these results demonstrate the ability of SS to relax cultured human mesangial cells, thus supporting a role for this peptide in the regulation of the glomerular filtration rate. The SS-dependent mesangial cell relaxation may be due to changes in the intracellular concentrations of cGMP, as a consequence of the activation of a particulate guanylate cyclase.
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PMID:Effects of somatostatin on cultured human mesangial cells. 762 80


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