Effect of 5-HT on basal and stimulated secretions of acid and pepsin and on gastric volume outflow in thein vivo gastrically and intestinally perfused cod,Gadus morhua

Abstract

Gastric acid and pepsin responses to 5-HT was measured, in cod, during gastric and intestinal perfusions. During basal conditions, both acid and pepsin secretions were stimulated by 0.25 mumol/kg X h of 5-HT. A higher dose, 1 mumol/kg X h inhibited acid secretion and stimulated the output of pepsin both during basal conditions and during stimulation with histamine or carbachol. Histamine and carbachol, when given alone, were powerful acid stimulators but in comparison with 5-HT poor pepsigogues. Most probably due to inhibition of gastric volume secretion, gastric outflow volume decreased during treatment with higher doses of 5-HT. However, when the intestinal perfusion was omitted and water support instead given by the intramuscular route, 5-HT induced a large increase in gastric outflow volume. Our results suggest that 5-HT may be a physiological regulator of acid and pepsin secretion in the fish. The dipsogenic effect seen in the absence of intestinal perfusion indicates that 5-HT may be involved also in the regulation of drinking.

Characterization with agonists of the histamine receptors mediating stimulation of gastric acid secretion in the Atlantic cod, Gadus morhua

“…The last factor, drinking, is low or absent during perfusion of the intestine at the rate presently used [6,9,10,11]. Generally, gastric volume outflow increased in proportion to stimulation of acid secretion, and decreased when acid secretion was inhibited (data not shown, cf.…”