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 effect of intrathecally injected substance P and somatostatin on spinal flexion reflex excitability was examined in decerebrate, spinalized, unanaesthetized rats. Substance P increased the excitability of the spinal cord to mechanical and thermal stimuli suprathreshold for C-afferents. Somatostatin had a similar effect with thermal, but not with mechanical stimuli. It is suggested that both peptides are released in association with C-afferent activation. Substance P may be released by polymodal nociceptors whereas somatostatin may be released by thermosensitive C-afferents.
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PMID:Substance P and somatostatin modulate spinal cord excitability via physiologically different sensory pathways. 242 89

Substance P, vasoactive intestinal polypeptide, somatostatin and neuropeptide Y-like immunoreactivity was studied by immunocytochemistry in the wall of the blood vessels of the small intestine of the cat, rat and guinea-pig. Immunoreactive nerve fibres were localized by means of the peroxidase-antiperoxidase (PAP) procedure, by use of antisera raised against these peptides. These neuropeptide-containing nerve fibres were widespread in association with the blood vessels and especially with the dense network of perivascular nerves supplying arterioles. At the ultrastructural level, immunoreactive nerve fibres were found very close to the basement membrane of the capillary walls. No immunoreactive nerve fibres were found in the wall of the veins. The anatomical findings of the present study are consistent with the proposal that several neuropeptides could function as neurotransmitters or neuromodulators in the control of blood flow in the small intestine.
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PMID:Ultrastructural localisation of substance P, vasoactive intestinal polypeptide, somatostatin and neuropeptide Y immunoreactivity in perivascular nerve plexuses of the gut. 242 25

Supramaximal repetitive field stimulation with pulses of 50 microseconds produced contraction of strips of bladder from rabbits and guinea-pigs. Atropine reduced responses at all frequencies to about 60% and the contraction was poorly maintained. With the double sucrose-gap technique large excitatory junction potentials (e.j.p.s) were recorded with superimposed action potentials. These were not reduced by atropine or phentolamine. Substance P (SP) produced contraction and increased the frequency of spontaneous action potentials recorded with micro-electrodes from bladder strips. Vasoactive intestinal peptide (VIP) produced relaxation and slowed action potentials in rabbit but had no effect in guinea-pig; neurotensin, somatostatin and leu-enkephalin were without action in either species. When the tissue was kept in contact with SP, a second application after 10 min produced only a small contraction suggesting that SP receptors were desensitized. However, the electrical response to field stimulation was unchanged and the mechanical response was increased. Chymotrypsin reduced mechanical responses to SP but had no effect on responses to field stimulation. The SP analogue, D-Pro2, D-Phe7, D-Trp9-SP, had no effect on responses to SP or to field stimulation. It is concluded that the bladder receives excitatory non-cholinergic innervation which is responsible for a large excitatory junction potential and contraction. Although SP can contract the detrusor muscle, it is unlikely that it is an excitatory transmitter or that any of the five peptides act as modulators of transmitter release.
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PMID:Non-cholinergic neurotransmission and the effects of peptides on the urinary bladder of guinea-pigs and rabbits. 242

A bland procedure, conducted in ice, is described for the extraction with HCl of smooth-muscle-contracting substances from plexus-containing ileal longitudinal muscle (l.m.) sheets obtained mainly from rabbits and some guinea-pigs. The spasmogenic activity in rabbit extracts was distinguished from acetylcholine, histamine and 5-hydroxytryptamine by antagonists; and from prostaglandins, by its insolubility in ether at acid pH and by pretreatment of the animals with indomethacin. The fact that it contracts the separated l.m. of the guinea-pig ileum, whether plexus-containing or plexus-free, and in atropine distinguishes it also from methionine-enkephalin, somatostatin, 13-norleucine motilin, bombesin, and cholecystokinin octapeptide (CCK8). This activity was partially purified, first by several partitions with ether at pH 1.4-2.2 and then by treatment at pH 4.5-5 with lead acetate. The virtual absence of ATP was confirmed by the firefly bioluminescence technique. The guinea-pig-ileum-contracting component in the partially purified extracts was destroyed by pepsin, chymotrypsin and DPCC-treated trypsin, indicating its peptide nature and distinguishing it from oxytocin, vasopressin, bradykinin, etc. In parallel assays the partially purified rabbit extracts were considerably more active than Substance P on jird or rat ascending colons than on the guinea-pig l.m., suggesting the presence of a second spasmogenic component in the extracts. In guinea-pig extracts the partially purified activity was 8-16 times greater when plexus-containing than when plexus-free, pointing to Auerbach's plexus as the source of the activity.
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PMID:Extraction and partial purification of spasmogenic substances in Auerbach's plexus. 242 21

Substance P (SP) and somatostatin (SS) are two widely distributed neuropeptides that within the vagus and sciatic nerves are localized predominantly in sensory fibers. The effect of diabetes mellitus on their content or transport in sensory nerves is unknown. With the nerve ligation technique, the peripheral orthograde 24-h transport of both peptides was quantified in the vagus nerve 3 days or 1 mo after induction of streptozocin (STZ) diabetes and in both the vagus and sciatic nerves after diabetes of 3 mo duration. In acute (3-day) diabetics, neuropeptide transport in the vagus was unaltered. After 1 mo, SP transport was significantly increased; content in unligated contralateral nerve was unaltered. Transport of SS was unchanged, and content in contralateral nerve was too low to reliably quantitate. After diabetes of 3-mo duration, transport of both peptides in the vagus nerve was increased in STZ-induced diabetic (STZ-D) rats versus both weight- and age-matched controls: SP 474 +/- 17 (N = 10) vs. 358 +/- 32 (N = 13) pg/24 h, STZ-D rats vs. controls, mean +/- SE, P less than .03; SS 29 +/- 4 vs. 20 +/- 3 pg/24 h, STZ-D rats vs. controls, P less than .02. In the sciatic nerve, SP transport and content were unaltered. SS content was significantly reduced: 17 +/- 3 vs. 30 +/- 3 pg/3-mm nerve segment, STZ-D rats vs. controls, P less than .01. SS transport in the sciatic nerve of diabetic rats was variably reduced (P less than .07), and transport rates were increased (1.41 +/- 0.13 vs. 0.96 +/- 0.10 mm/h.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Substance P and somatostatin content and transport in vagus and sciatic nerves of the streptozocin-induced diabetic rat. 243 76

Substance P, present in primary sensory neurones, seems to take part in nociceptive transmission within the trigeminal system. Substance P, released by peripheral axons of these neurones, induces vasodilatation, plasma extravasation, miosis, conjunctival and nasal congestion. All these effects bear some similarity to symptoms of cluster headache and migraine attack. Opiates and somatostatin inhibit the release of substance P from primary sensory neurones and relieve both pain and autonomic symptoms of cluster headache attack. Plasma substance P-like immunoreactivity was decreased during spontaneous attack of cluster headache and migraine and during histamine precipitated attack of cluster headache. Taken together these data suggest that substance P and endogenous opioids could be implicated in the pathophysiology of cluster headache and migraine.
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PMID:Substance P and enkephalins: a creditable tandem in the pathophysiology of cluster headache and migraine. 243 12

The effects of a range of neuropeptides were investigated on the membrane potential of the Schwann cells of the giant nerve fibre of the tropical squid. Vasoactive intestinal peptide (VIP) produced a dose-dependent, long-lasting hyperpolarization of the Schwann-cell membrane potential. Among peptides structurally related to VIP, similar effects were produced by peptide histidine isoleucine (PHI) but not by secretin and glucagon. Substance P and somatostatin also hyperpolarized the Schwann-cell membrane potential but via receptor systems distinct from those activated by VIP. Methionine enkephalin ([Met]-enkephalin) blocked the actions of all the above peptides as well as the effects of DL-octopamine and carbachol. The actions of [Met]-enkephalin upon the VIP responses were antagonized by naloxone. VIP produces its effects on the Schwann-cell membrane potential via a receptor system that is independent from those described previously which mediate the effects of carbachol and DL-octopamine. However, VIP can potentiate the effects of the latter systems. The actions of VIP on the Schwann cell are unlikely to be mediated via changes in adenosine 3',5'-cyclic monophosphate (cyclic AMP) levels and are insensitive to changes in the level of extracellular calcium in the superfusate. The actions of VIP are, however, potentiated in the presence of low concentrations of lithium ions suggesting that the VIP receptor may mediate its effects by inducing the hydrolysis of polyphosphatidylinositols in the Schwann-cell membrane. Evidence is presented for the existence of an endogenous VIP-like component in the normal hyperpolarizing action of giant-axon activity on the membrane potential of the Schwann cell.
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PMID:Peptidergic modulation of the membrane potential of the Schwann cell of the squid giant nerve fibre. 243 97

Our studies have clearly shown that neuropeptides have a profound effect on immunoglobulin synthesis both in vivo and in vitro. The effects varied according to the neuropeptide added or the tissue from which the lymphocytes were obtained. Substance P caused the most pronounced enhancement of both functions, especially in Peyer's patch cells, where it selectively increased IgA synthesis. Somatostatin was inhibitory, and the effect of vasoactive intestinal peptide varied according to the source of the cells. We have previously shown that neuropeptides also cause mast cell secretion and that only substance P was effective in this regard on intestinal mucosal mast cells. Therefore, we looked for microanatomic relationships between peptidergic nerves and immune effector cells. Mast cells appear to have structural associations with neuropeptides-containing nerves in the intestine. Nerve growth factor, known to promote the growth of sensory afferent and sympathetic nerves, has significant direct effects on mast cells. In vitro, this substance caused enhanced antigen mediated histamine release and, in vivo, extensive mast cell hyperplasia. Also, in humans, we were able to produce increased numbers of mast cell/basophil colonies from peripheral blood in the presence of nerve growth factor.
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PMID:Neuropeptides and immunity. 244 42

From rat brain, a membrane bound substance P-degrading endopeptidase (SPE) was purified 1580 fold to near homogeneity. After extraction with 10 mM CHAPS, the enzyme preparation was subjected to ion exchange chromatography on DEAE-cellulose, adsorption chromatography on hydroxyapatite, gelfiltration through Ultrogel AcA 44 and FPLC on Mono Q. This enzyme of 70,000 molecular weight is optimally active at pH 7.5. Metal chelators (EDTA and EGTA) and sulfhydryl modifying reagents (N-ethylmaleimide and p-chloromercuriphenylsulfonic acid) are strongly inhibitory while the serine-protease inhibitor diisopropyl-fluorophosphate does not effect the enzyme activity. The enzyme is strongly inhibited by bacitracin but not by phosphoramidon and captopril. Degradation of substance P is strongly inhibited by neurotensin, somatostatin, ACTH 1-39, and less effectively by LHRH but not by Leucine-enkephalin. Substance P is preferentially hydrolyzed at the Gln6-Phe7 peptide bond but fragmentation at the Pro4-Gln5, Gln5-Gln6,Phe7-Phe8 and Gly9-Leu10 bonds was also observed.
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PMID:A membrane bound substance P degrading endopeptidase from rat brain. 244 28

A considerable number of neuropeptides have been localized immunohistochemically in the area of the locus coeruleus of the rat. The objective of this study was to assess the actions of some of these transmitter candidates on spontaneously active locus coeruleus neurons in vitro. The effects of bath-applied peptides on the discharge rate of individual locus coeruleus neurons were investigated. A midpontine slice preparation of the gerbil brain was used. Excitatory dose-dependent effects were found with four peptides with the following rank order of potency: Substance P, (Arg8)-vasopressin, neurotensin, ACTH1-24. Somatostatin hyperpolarized all neurons tested. Given the pronounced effects seen with substance P, somatostatin and vasopressin in the nanomolar range, it is conceivable that these peptides may have a role in regulating neuronal activity in locus coeruleus.
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PMID:Comparative investigations on the actions of ACTH1-24, somatostatin, neurotensin, substance P and vasopressin on locus coeruleus neuronal activity in vitro. 244 59


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