تاثير اتساع مري بر جريان خون معده ترشح هورمون هاي گاسترين و سوماتوستاتين در موش صحرايي

Effect of esophageal distension on gastric blood flow, gastrin and somatostatin secretion in rat

Introduction: There are many studies about the inhibitory effect of the esophageal distention (ED) on gastric motility. Recently, it has been shown that ED decreases gastric secretions. It is well established that the inhibitory effect of ED is mediated by activation of vago-vagal inhibitory reflex. However, there is not any investigation about the effect of the reflex on the gastric blood flow and release of gastric hormones. The aim of this study was to investigate the effect of esophageal distention (ED) on gastric blood flow and release of gastrin and somatostatin hormones. Methods: Seventy-nine male Wistar rats (175-230 g) were used in this study. The rats were deprived of food but not water 24 h before the experiments. Animals underwent tracheostomy and laparotomy under urethane anesthesia (1.2 g/kg, i.p.). A catheter was inserted in the stomach through the duodenum for gastric distension. The esophagus was cannulated with a balloon orally to distend distal portion of the esophagus (0.3 ml, 10 min). Saline was used for gastric distension (1.5 ml/100 g b.w., pH 7 and 37 °C). Gastric blood flow was measured by a Laser Doppler flow meter. Serum gastrin and plasma somatostatin levels were assessed by RIA method. Vagotomy was carried out in a group to reveal the role of vagus nerve in this action. Results: ED reduced the blood flow of gastric proximal portion (P<0.001) but the antrum blood flow was unaffected by ED. Cervical vagotomy abolished the inhibitory effect of the ED on the proximal area blood flow. Serum gastrin and plasma somatostatin levels were unaffected by ED. Conclusion: Removal of the inhibitory effect of ED after vagotomy shows that the vagus nerve is involved in the inhibitory effect on gastric blood flow.