5-Hydroxytryptamine can antagonize the ability of metoclopramide and SCH 23390 to enhance electrical field stimulation-evoked contractions of guinea-pig isolated stomach muscle

Abstract

Electrical field stimulation of guinea-pig stomach strips caused frequency related contractions that were enhanced by metoclopramide and SCH 23390 (10−7 −10−5 M) and antagonized by atropine (5 times 10−8 M. 5-HT (3 times 10−8 −3 times 10−5 M) antagonized the ability of metoclopramide and SCH 23390 to enhance the contractions. It is concluded that metoclopramide and SCH 23390 can enhance electrical field stimulation-induced contractions in the stomach strips by a 5-HT receptor blockade which can facilitate cholinergic mediated contractions.