SUMATRIPTAN, A SELECTIVE 5-HT1 RECEPTOR AGONIST, INDUCES A LAG PHASE FOR GASTRIC-EMPTYING OF LIQUIDS IN HUMANS

Sumatriptan, a 5-hydroxytryptamine(1) (5-HT1) receptor agonist at ente ric neuronal 5-HT receptors, causes a relaxation of the gastric fundus and inhibition of antral contractile activity. The present study exam ined the effect of sumatriptan on gastric emptying of solids and Liqui ds in humans. In eight healthy subjects the gastric emptying rate for Liquids and solids was measured using the carbon-labeled glycine and o ctanoic acid breath test after subcutaneous administration of placebo or sumatriptan. Sumatriptan increased the gastric half-emptying time o f liquids (P < 0.0005) and induced a prolonged lag phase for liquids ( P < 0.0005) in all subjects. Sumatriptan increased gastric half-emptyi ng time (P < 0.005) and the lag phase of solids (P < 0.05) in all subj ects. In two healthy subjects gastric emptying of liquids and solids a ft er subcutaneous administration of sumatriptan was studied by radios cintigraphy. Radioscintigraphy confirmed the delayed emptying and the prolonged lag phases after sumatriptan. In conclusion, sumatriptan del ays gastric emptying of solids and liquids in healthy subjects. Moreov er, sumatriptan induces a lag phase for Liquids. The mechanism by whic h sumatriptan alters gastric emptying remains to be studied.