Comparison of Physiological and Pharmacological Stimulation of Acid Secretion in Vagally Innervated and Denervated Gastric Pouches in the Same Dog

Abstract

The double-pouch dog with one vagally innervated Amdrup pouch (AP) taken from the lesser curvature side of the stomach and one denervated Heidenhain pouch (HP) from the corporo-fundic part permitted comparison of gastric secretion from innervated and denervated mucosa at the same time in the same animal. Food stimulation with a mixture of liver, heart, and bonemeal showed significantly higher response from AP than from HP for all doses, and the difference between the pouches in total acid output was constant for all doses, indicating that the relative contribution of vagal innervation is diminished when the size of the protein meal is increased. The difference between innervated and denervated mucosa is achieved by an immediate high response from the AP. After 150 min the responses to the larger meals were identical in the two pouches. Acid output during stimulation with pentagastrin reached 64.4% of maximal response to histamine in the AP and 36.2% in the HP, the innervated mucosa giving a statistically significant higher response for all doses. Absence of innervation gave an HP response similar to non-competitive inhibition with significantly lower calculated maximal response and a CD₅₀ not different from the CD₅₀ for the AP. Twenty-four-hour secretion studies during optimal physiological conditions with the dog fed two daily meals of standard composition showed sparse secretion from denervated mucosa, whereas a great part of the capacity of innervated mucosa is utilized during daily conditions.

Key-words:

• Food
• gastric hydrochloric acid
• histamine
• pentagastrin
• vagus nerve