The rat isolated stomach sheet; an in vitro model for the study of the physiology and pharmacology of gastric acid secretion.

The development of an isolated stomach preparation from immature rats is described. Acid secretion was measured by titration of mucosal samples taken at 15 min intervals. Nonstimulated acid secretion was generally in the range 60-180 mumol H+g-1 wet weight of mucosa hr-1 and was maintained for up to 5.5 hr. A small proportion of stomachs (20%) had a higher level of spontaneous secretion which fell to the more usual low level within 1.5 hr. Pentagastrin (1.3 X 10(-8) M-1.3 X 10(-7) M), bethanechol (2 X 10(-6) M-3 X 10(-5) M), histamine (5 X 10(-6) M-5 X 10(-4) M) and theophylline (2 X 10(-4) M-1 X 10(-3) M) induced concentration-dependent stimulation of acid secretion. Linear log-dose response relationships were obtained for each of the four stimulants. The regression coefficients from each drug study, calculated over a similar increase in concentration, were not significantly different from one another. The maximal secretory rates recorded with the four secretagogues were comparable, range 152.5-226.0 mumol H+g-1hr-1. The methodology and results are compared with other mammalian in vitro stomach preparations currently used to study the physiology and pharmacology of gastric acid secretion.