Histamine stimulated acid secretion in the isolated perfused porcine stomach: An in vitro model of acid secretion

Many gut peptides effect parietal cell acid secretion through intermediary mechanisms which can not be studied in isolated parietal cell or gastric gland systems. To more effectively investigate these mechanisms, we have developed an isolated perfused stomach model for studying acid secretion under conditions which maintain the integrity of the organ. The aim of this study was to develop and validate the model by comparing histamine (H) stimulated acid secretion in the intact pig and in the isolated perfused pig stomach. In anesthetized pigs (20 kg), the pylorus and esophagus were ligated and the stomach drained via a gastrostomy tube. In the in vitro studies, the stomach, duodenum, and pancreas were removed en bloc and placed into an isolated organ system and perfused with oxygenated krebs Ringers bicarbonate solution containing 10% porcine blood. H was infused in both models for one hour periods in graded doses of 2, 4, and 8 μg/kg/min. Basal level was 5 ± 1 μmol/min in both groups. H infusions of 2, 4, and 8 μg/kg/min in the anesthetized pig resulted in acid secretion of 133 ± 8 μmol/min, 241 ± 5 μmol/min and 298 ± 23 μmol/min, respectively. H infusions at the same levels in the isolated stomach resulted in acid secretion of 16 ± 5 μmol/min, 28 ± 9 μmol/min and 34 ± 9 μmol/min, respectively. H significantly stimulated acid secretion in vivo and in vitro at all three doses (p < 0.05). This study has demonstrated that a histamine stimulated dose response curve for acid secretion can be reliably obtained from an isolated perfused porcine stomach.