CENTRAL REGULATION OF GASTRIC-EMPTYING OF SOLID NUTRIENT MEALS BY CORTICOTROPIN-RELEASING FACTOR

Central regulation of gastric emptying of a solid nutrient meal and sp atial and temporal parameters of gastro-pyloro-duodenal contractions b y corticotropin-releasing factor (CRF) were investigated in conscious dogs. Intracerebroventricular (ICV) infusion of CRF at 0.033 nmol kg(- 1) min(-1) for 15 min in a volume of 0.2mL significantly delayed the t otal gastric emptying time of the meal. ICV infusion of CRF also incre ased the mean frequency of proximal duodenal contractions and decrease d the percentage of distally propagating contractions in the whole duo denum. The remaining parameters of pyloric and duodenal contractions w ere not affected. A prior ICV infusion of I-helical CRF9-41 (0-166 nmo l kg(-1) min(-1) for Is 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 o f gastric emptying. Bilateral truncal vagotomy significantly delayed t he gastric emptying time of the solid nutrient meal. However, after va gotomy, ICV infusion of CRF had no effect on gastric emptying time or the spatial and temporal parameters of gastro-pyloro-duodenal contract ions. In conclusion, CRF, the mediator of stress response, delays the total gastric emptying time of solid nutrient meals. The delay in gast ric emptying may not be due to a change in the spatial and temporal pa rameters of gastric or pyloric contractions, but mainly due to changes in the parameters of duodenal contractions. The central effects of CR F on gastric emptying and duodenal contractions may be mediated by the vagus nerves.