Possible mechanism of stimulation of gastrin secretion by exogenous serotonin in rats.
The effect of 6-hydroxydopamine, propranolol, phentolamine, alpha-methyl-tyrosine and alpha-methyl-tyrosine plus propranolol on serotonin-stimulated gastrin secretion in rats has been examined. Gastrin secretion in response to administration of serotonin alone (10 mg/kg i.p.) was significantly reduced in rats pretreated with 6-hydroxydopamine or with propranolol. These results suggest that the effect of exogenous serotonin on gastrin secretion can be described as sympathomimetic and indirect. The serotonin-stimulated gastrin secretion was significantly enhanced by previous administration of phentolamine. Pretreatment with alpha-methyl-tyrosine also elevated serotonin-stimulated gastrin secretion, indicating that in the presence of diminished concentrations of the catecholamines, the influence of exogenous serotonin on secretion by G cells is increased. This enhancement in the serum gastrin levels was also reduced to a significant extent by simultaneous administration of propranolol, which suggested the activation of G-cell beta-adrenergic receptors after serotonin administration.
D000818:Animals; D004357:Drug Synergism; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism; D005755:Gastrins / Q000378:metabolism*; D008297:Male; D051381:Rats; D011941:Receptors, Adrenergic / Q000494:pharmacology*; D011943:Receptors, Adrenergic, beta / Q000494:pharmacology*; D012701:Serotonin / Q000494:pharmacology*; D013268:Stimulation, Chemical
D005755:Gastrins; D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D012701:Serotonin