Gastrointestinal motor effects of corticotropin-releasing factor in mice

Abstract

The present investigation examined the effects of centrally and peripherally administered corticotropin-releasing factor on gastric emptying and gastrointestinal transit in mice. Corticotropin-releasing factor, given either intracerebroventricularly or intrathecally, caused a dose-dependent inhibition of gastric emptyping and gastrointestinal transit. Intravenous or intraperitoneal administration of corticotropin-releasing factor, while 5- to 7-fold less potent than after central injection, produced an equivalent level of effect. α-Helical corticotropin-releasing factor 9–41, a corticotropin-releasing factor receptor antagonist, blocked the effects of intracerebroventricularly administered corticotropin-releasing factor when the antagonist was given concurrently by the intracerebroventricular, but not by the intraperitoneal, route. Conversely, corticotropin-releasing factor, when given peripherally, was antagonized equally well by intracerebroventricular or intraperitoneal administration of the antagonist. The inhibition of gastric emptying induced by corticotropin-releasing factor was reduced by pretreatment with the ganglionic blocking agent, chlorisondamine, and in adrenalectomized mice, but this effect was not antagonized by naloxone. These findings provide evidence for an action of corticotropin-releasing factor within the central nervous system, as well as a peripheral site of action, to inhibit gastric emptying in the mouse. The gastrointestinal motor effects of corticotropin-releasing factor are not mediated through opioid mechanisms although their full expression may require intact autonomic innervation and adrenal function.