Central regulation of gastric emptying of solid nutrient meals by corticotropin releasing factor

Central regulation of gastric emptying of a solid nutrient meal and spatial and temporal parameters of gastro-pyloro-duodenal contractions by corticotropin-releasing factor (CRF) were investigated in conscious dogs. Intracerebroventricular (i.c.v.) infusion of CRF at 0.033 nmol kg-1 min-1 for 15 min in a volume of 0.2 mL significantly delayed the total gastric emptying time of the meal. I.c.v infusion of CRF also increased the mean frequency of proximal duodenal contractions and decreased the percentage of distally propagating contractions in the whole duodenum. The remaining parameters of pyloric and duodenal contractions were not affected. A prior i.c.v. infusion of I-helical CRF9-41 (0.166 nmol kg-1 min-1 for 15 min in a volume of 0.2 mL) blocked the central effects of CRF on gastric emptying time and the duodenal contractions. Central infusion of CRF had no significant effect on the lag phase of gastric emptying. Bilateral truncal vagotomy significantly delayed the gastric emptying time of the solid nutrient meal. However, after vagotomy, i.c.v. infusion of CRF had no effect on gastric emptying time or the spatial and temporal parameters of gastro-pyloro-duodenal contractions. In conclusion, CRF, the mediator of stress response, delays the total gastric emptying time of solid nutrient meals. The delay in gastric emptying may not be due to a change in the spatial and temporal parameters of gastric or pyloric contractions, but mainly due to changes in the parameters of duodenal contractions. The central effects of CRF on gastric emptying and duodenal contractions may be mediated by the vagus nerves.