AJP - Gastrointestinal and Liver Physiology, Vol 240, Issue 3 245-G249, Copyright © 1981 by American Physiological Society
Effect of sodium taurocholate on secretion by amphibian gastric mucosa in vitro
W. D. Rees, A. Garner, K. H. Vivian and L. A. Turnberg
Effects of sodium taurocholate on the electrical and secretory activity of
amphibian gastric mucosa have been studied in vitro. Exposure of the
luminal surface of fundic mucosa to high concentrations (5 X 10(-2) M) at
low pH (2.0 and 3.0) produced a marked fall in potential difference and
electrical resistance. At lower concentrations (10(-3) to 10(-4) M) and
higher pH (7.4), taurocholate did not alter the electrical properties but
significantly increased net acidification from 1.39 +/- 0.27 to 2.01 +/-
0.18 mueq . cm-2 . h-1 (means +/- SE; P less than 0.01). Pretreatment of
fundic mucosa with cimetidine resulted in net alkaline secretion (0.27 +/-
0.07 mueq . cm-2 . h-1), and addition of taurocholate (10(-4) M) to the
luminal surface at pH 7.4 converted net alkalinization to net acidification
(0.94 +/- 0.28 mueq . cm-2 . h-1). This response was not inhibited by
atropine (10(-5) M) or somatostatin (10(-6) M) but exhibited marked
tachyphylaxis. Taurocholate (10(-4) M) inhibited alkaline secretion in
thiocyanate-treated fundic mucosa (0.63 +/- 0.04 to 0.14 +/- 0.09 mueq .
cm-2 . h-1; P less than 0.001) and in spontaneously alkaline-secreting
antral mucosa (0.36 +/- 0.12 to 0.09 +/- 0.06 mueq . cm-2 . h-1; P less
than 0.05), but acidification did not occur. Apparent stimulation of acid
secretion and simultaneous inhibition of alkaline secretion of sodium
taurocholate may play a role in the pathogenesis of mucosal damage by bile.
