Abdominal surgery-induced delayed gastric emptying in rats: Role of CRF and sensory neurons

The role of peripheral corticotropin-releasing factor (CRF) and afferent pathways in mediating abdominal surgery-induced delayed gastric emptying was investigated using an intravenous injection of the competitive CRF antagonist α-helical CRF_9-41 and capsaicin pretreatment in adult fasted rats. Gastric emptying of a non-caloric solution was measured by the phenol red method. Intravenous CRF (0.13 nmol) inhibited by 65% gastric emptying. CRF effect was completely reversed by simultaneous intravenous injection of α- helical CRF_9-41 (13 nmol). Abdominal surgery under enflurane anesthesia inhibited gastric emptying by 60% measured 3 h postoperatively. Enflurane anesthesia alone had no effect on gastric emptying 3 h after exposure. Abdominal surgery-induced delay of gastric emptying was reversed by 46, 60, and 100% by capsaicin pretreatment (125 mg/kg, -3 wk), intravenous injection of α-helical CRF_9-41 (13 nmol), and combined pretreatments with capsaicin and CRF antagonist, respectively. Capsaicin and α-helical CRF_{9- 41} given alone or in combination did not influence gastric emptying. These results indicate that peripheral CRF receptors along with capsaicin-sensitive afferent neurons contribute to somatovisceral stress (abdominal surgery)- induced delayed gastric emptying.