Corticotropin-releasing factor (CRF) has been implicated as a central nervous system mediator of stress. This study examined the effects of CRF and stress on gastric secretory and gastrointestinal motor functions in rats. Partial body restraint as a stress-producing stimulus significantly decreased gastric acid secretion, gastric emptying, and small bowel transit but markedly increased large bowel transit. Corticotropin-releasing factor given cerebroventricularly mimicked the gastrointestinal secretory and motor responses induced by partial body restraint. Cerebroventricular administration of a specific CRF receptor antagonist, alpha-helical CRF-(9-41), but not of the CRF fragment CRF-(1-20), prevented the gastrointestinal secretory and motor responses elicited either by partial body restraint or by exogenous administration of CRF in a dose-dependent fashion. These results suggest that the gastrointestinal secretory and motor responses in rats produced by stress (partial body restraint) are mediated by the endogenous release of CRF. They also indicate that CRF exerts its central nervous system actions on the gastrointestinal tract by a receptor-mediated event.