Central nervous system action of corticotropin-releasing factor to inhibit gastric emptying in rats

The present study evaluates the central nervous system action of rat corticotropin-releasing factor (CRF) on gastric emptying of a liquid meal in conscious rats using the phenol red method. Intracisternal injection of CRF (63-210 pmol) dose-dependently inhibited gastric emptying of a liquid meal by 37-80%. Peptide action was rapid in onset, long acting, and not mimicked by intracisternal injection of growth hormone-releasing factor. Intracisternal CRF-induced inhibition of gastric emptying was reversed by subdiaphragmatic vagotomy but not by naloxone pretreatment or adrenalectomy. Intravenous injection of CRF (21-630 pmol) also dose-dependently inhibited gastric emptying. CRF antiserum blocked the effect of intravenous but not of intracisternal injection of CRF (63 pmol). These results demonstrated that CRF injected in a picomole amount into the cerebrospinal fluid acts within the brain to inhibit gastric emptying of a liquid meal through vagal-dependent pathways.