SCH 23390 can enhance field stimulation-induced contractions of longitudinal smooth muscle from guinea-pig stomach.

Field stimulation-induced contractions of guinea-pig stomach longitudinal muscle strips were enhanced by metoclopramide (a D-2 receptor antagonist) and SCH 23390 (a D-1 receptor antagonist) but not by cis-flupenthixol (a D-1 and D-2 receptor antagonist) or sulpiride (a D-2 receptor antagonist). SCH 23390 is the first non-benzamide neuroleptic drug shown to enhance cholinergic mediated contraction responses of gastric smooth muscle, but the response does not appear to reflect a D-1 receptor antagonism.