Effect of pyloric blockade and infusion of histamine or pentagastrin on gastric secretion in horses

Objective—To determine the origin of the nonacid (nonparietal) component of gastric secretions in horses induced by pentagastrin infusion. Animals—6 horses. Procedure—A Latin square design was used, involving 6 horses, 3 treatments, and 2 duodenal intubation conditions (catheter with balloon to obstruct pylorus [B] or without balloon allowing movement of contents between stomach and duodenum [NB]). Each horse had an indwelling gastric cannula and a catheter positioned in the duodenum. Gastric and duodenal contents were collected during 15-minute periods. Each experiment consisted of serial collection periods: baseline; infusion of pyrilamine maleate (1 mg/kg of body weight, IV); not treated; and IV infusion of saline (0.9% NaCl) solution alone, saline solution containing pentagastrin (6 µg/kg·h), or saline solution containing histamine (30 µg/kg·h). Volume of samples was recorded, and electrolyte concentrations were measured. Results—Pentagastrin and histamine stimulated maximal acid output; however, duri...