Serotonin‐Induced Short‐Circuit Current in Pig Jejunum

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Abstract
This paper presents the effects of serotonin (5-HT) on short-circuit current (SCC), sodium and chloride fluxes, and prostaglandin E2 release in pig jejunum, using the Ussing-chamber technique. 5-HT elicited a dose-dependent increase in SCC, yielding an EC50 of 6 ± 4 μM and EMAX of 77± 8 μA. cm−2 using about 100 ±. Inhibited sodium absorption and stimulated chloride secretion carried part of the 5-HT-induced SCC. 5-HT caused a dose-independent PGE2 release, and indomethacin reduced the SCC-inducing effect of 5-HT by 40%. Octreotide, a long-lasting somatostatin analogue, also reduced 5-HT-induced SCC by about 40%, while tetrodotoxin (TTX) did not alter the effect of 5-HT. In conclusion, 5-HT causes a dose-dependent indomethacin and octreotide-sensitive, and TTX-insensitive increase in SCC, and a chloride secretion and inhibited sodium absorption and an increased release of PGE2 in pig jejunum in vitro. Abbreviations: 5-HT, 5-hydroxytryptamine, serotonin; Cl−, chloride; Na+, sodium; HCO3−, bicarbonate; J, ion flux; PGE2, prostaglandin E2; TTX, tetrodotoxin; AUC, area under the curve; T1/2, halftime.