Secretin inhibits gastric emptying in rats via a capsaicin-sensitive vagal afferent pathway.

In awake rats, fitted with chronic gastric fistulas, secretin (30 and 300 pmol intraperitoneal, i.p.) inhibited gastric emptying of a non-nutrient liquid by 16% (NS) and 38% (P < 0.01) respectively. Functional ablation of vagal, but not spinal, capsaicin-sensitive afferents reversed the action of secretin by 61%. Inhibition of gastric emptying induced by cholecystokinin (CCK) (30 pmol i.p.) was reversed by around 50% by ablation of either the vagal or spinal capsaicin-sensitive afferent pathway. These results suggest that hormones released after a meal can inhibit gastric emptying via activation of visceral afferent pathways.