Gastric function before and after gastric sympathectomy and subsequent truncal vagotomy

A surgical technique for selective gastric sympathectomy (SGS) has been developed by total devascularization of the dog stomach with immediate revascularization via the divided and reanastomosed splenic artery and vein. Splenectomy is also performed to divert the entire splenic blood-flow to the stomach. Several months later biopsy of vessels from the gastric wall shows that all catecholamine staining is lost. Blood-flow studies using the aminopyrine clearance method show that a significant decrease in blood-flow occurs, particularly during maximal acid secretion. The effects of SGS on the gastric acid responses of 5 dogs were: (1) increased responsiveness to histamine with a left shift of the dose-response curve (D50 = 35 +/- 5 before, and 17 +/- 4 micrograms kg-1 hr-1 after; p less than 0.05); (2) increased response to insulin hypoglycemia (peak 15 min output = 3.5 +/- 0.9 before, and 5.5 +/- 0.9 mMol after; p less than 0.05); but (3) a reduction of acid response to meal (peak 15 min output = 7.1 +/- 0.9 before, 3.7 +/- 1 after; p less than 0.05). Propranolol, on the other hand, had no effect on the response to meal before SGS but enhanced it after SGS restoring the response to pre-SGS levels. Subsequent vagotomy abolished acid response to insulin but did not alter the post-SGS response to a meal. We conclude that the sympathetics exert a beta-adrenergic inhibitory influence on gastric acid response to insulin and histamine but not to food. Following SGS, the enhancing effect of propranolol probably implies supersensitivity of the stomach to circulating catecholamines.