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Query: UNIPROT:P15088 (
mast cell
)
14,925
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Intravenous injections of neurotensin (NT) (0.5, 1 and 2 nmoles kg-1) evoked dose-dependent increases in histaminemia and hematocrit, and marked hypotensive effect, in anesthetized rats. The increase of plasma histamine was rapid in onset (within sec), peak plasma histamine being reached in less than 2 min. The decline of plasma histamine was gradual and almost complete 15 min after injection of NT. The hematocrit increased slowly, maximum values being obtained 5-10 min after injection of NT, and it persisted throughout the period of observation. The hypotensive effect of NT was rapid in onset and of prolonged duration. Compound 48/80, a well known histamine liberator and
mast cell
depletor, produced variations of blood pressure, of hematocrit and of plasma histamine very similar to those elicited by NT. Pretreatment of rats with cromoglycate, a well known
mast cell
stabilizer, or with dexamethasone, inhibited markedly the changes of histaminemia, of hematocrit and of blood pressure evoked by NT and compound 48/80. The results clearly suggest that the effects of NT on blood pressure and on vascular permeability in rats are mediated to some extent by
mast cell
histamine.
Hexamethonium
, a ganglion blocker, inhibited slightly the effect of NT on histaminemia but it did not block NT-induced changes of hematocrit. However, the hypotensive effect of NT was severely blocked in hexamethonium-treated rats. These results were interpretated as an indication that hexamethonium prevents NT-induced hypotension not merely by reducing the mobilization of
mast cell
histamine by NT but most likely by interfering with the mechanism by which NT and/or its
mast cell
mediators produce their effects on blood pressure.
...
PMID:Influence of various drugs on the variations of blood pressure, hematocrit and plasma histamine caused by neurotensin and compound 48/80 in rats. 613 90
Treatment 20 min beforehand with an inhibitor of nitric oxide (NO) synthesis NW-nitro-1-arginine methyl ester (L-NAME) (12.5, 25, 50 or 100 mg/kg, s.c.), dose-dependently intensified gastric glandular mucosal ulceration produced by cold-restraint stress.
Hexamethonium
(20 mg/kg) or atropine (1 mg/kg) pretreatment s.c. 20 min before stress strongly antagonised stress-evoked ulceration, as well as the ulcer-potentiating effects of L-NAME when either cholinoceptor antagonist was given concurrently with the NO inhibitor. Stress-induced
mast cell
degranulation was not worsened by L-NAME pretreatment. The findings suggest that NO could confer partial protection against stress-induced gastric ulcer formation; its activity is triggered off by the ulcerogenic mechanism of stress.
...
PMID:Nitric oxide inhibition intensifies cold-restraint induced gastric ulcers in rats. 809 77
Chronic nicotine treatment worsens stomach mucosal damage by cold (4 degrees C) and restraint (stress): it dose- and time-dependently intensifies stress-evoked gastric glandular ulceration,
mast cell
degranulation and motility. Nicotine 50 micrograms/ml drinking water, given ad libitum to female Sprague-Dawley rats for 10 days, increases the sensitivity of the isolated stomach strip to acetylcholine-induced contractions; atropine abolishes this action. The isolated anococcygeus muscle from nicotine-treated male rats shows increased sensitivity to noradrenaline-induced contractions, but not to those by acetylcholine.
Hexamethonium
or atropine pretreatment antagonises stress-induced gastric effects in nicotine-drinking rats. Muscarinic M1- and M2-, but not M3-, receptor block (by pirenzepine, AF-DX 116BS and HHSiD, respectively) inhibits stress ulcer formation in female rats. Although tobacco smoking has been reported to increase free radical formation, mucosal xanthine oxidase which initiates free radical formation is uninfluenced by nicotine; antagonising this enzyme (by allopurinol) or hydroxyl free radical scavenging (by dimethylsulfoxide) does not lessen the effect of nicotine on stress-evoked ulceration. The findings suggest that chronic nicotine treatment produces partial ganglionic blockade of the vagal nerve which leads to muscarinic receptor supersensitivity. This phenomenon contributes significantly to the ulcer-worsening mechanism; muscarinic M1- and M2-receptors appear to be involved. The gastric ulcer-aggravating effect of nicotine in stressed rats appears not to be due to increased free radical formation.
...
PMID:Nicotine and gastric ulcers in stress. 829 87
We determined the effects of immobilization stress on rat colonic mucus release and
mast cell
degranulation and examined whether corticotropin releasing factor (CRF) was involved in these responses. After 30-min immobilization, rats were killed, colonic mucosal explants were cultured, and levels of rat mast cell protease II (RMCP II) and prostaglandin E2 (PGE2) were measured. Mucin release from explants was assayed by incorporation of [3H]glucosamine into colonic mucin and by histological evaluation of goblet cell depletion. Stress caused significant increases of colonic RMCP II, PGE2, and mucin release and fecal pellet output and caused an approximately 10-fold increase in colonic mucosal levels of cyclooxygenase-2 (COX-2) mRNA. These stress-associated changes were reproduced by intravenous or intracerebral injection of CRF in conscious, nonstressed rats. Pretreatment of rats with the CRF antagonist alpha-helical-CRF9-41, hexamethonium, atropine, or bretylium, or the
mast cell
stabilizer lodoxamide inhibited stress-induced release of RMCP II, PGE2, and mucin, whereas indomethacin prevented mucin release but not
mast cell
degranulation.
Hexamethonium
and CP-96,345, a substance P antagonist, inhibited fecal pellet output caused by stress. We conclude that CRF released during immobilization stress increases colonic transit via a neuronal pathway and stimulates colonic mucin secretion via activation of neurons and mast cells.
...
PMID:Acute stress causes mucin release from rat colon: role of corticotropin releasing factor and mast cells. 894 4