title: Studies of acid and alkaline secretion by rabbit gastric fundus in vitro: effect of low concentrations of sodium taurocholate.
abstract: The effect of low concentrations of sodium taurocholate on the secretory and electrical activity of isolated rabbit fundic mucosa has been studied. Fundic mucosa maintained a stable potential difference (10.2 +/- 0.6 mV, n = 70) and electrical resistance (85 +/- 6 omega . cm-2, n = 70) and the majority of preparations spontaneously secreted acid (2.85 +/- 0.31 mumol . cm-2 . h-1, n = 70). Histamine (10(-5) and 10(-4) M) and carbachol (10-4 M) increased acid secretion, and these responses were prevented by cimetidine (10(-3) M) and atropine (10(-5) M), respectively. Mucosal application of taurocholate (10(-4) and 10(-3) M) increased net acidity without altering electrical activity. This response exhibited tachyphylaxis, was not altered by pretreating the tissues with cimetidine (10(-3) M), atropine (10(-5) M), or somatostatin (10(-6) M), and occurred in mucosas maximally stimulated by histamine. Sodium thiocyanate (6 x 10(-2) M, serosal side) inhibited spontaneous acid secretion revealing net alkalinization (0.83 +/- 0.05 mumol . cm-2 . h-1, n = 58) that was completely inhibited by anoxia and potassium cyanide (10(-2) M) and markedly reduced by 2,4-dinitrophenol (10(-4) M). Some fundic preparations spontaneously secreted alkali (1.20 +/- 0.20 mumol . cm-2 . h-1, n = 6) after an initial period of acid secretion. Mucosal-side taurocholate (10(-3) M) converted net alkali secretion by both thiocyanate-treated and spontaneously-secreting mucosas to acid secretion without affecting electrical conductance. These secretory responses may be implicated in the pathogenesis of gastric mucosal damage by bile salts.
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D002927:Cimetidine / Q000494:pharmacology; D004553:Electric Conductivity; D005744:Gastric Acid / Q000378:metabolism; D005748:Gastric Fundus / Q000187:drug effects / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism; D006632:Histamine / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D011817:Rabbits; D013004:Somatostatin / Q000494:pharmacology; D013656:Taurocholic Acid / Q000494:pharmacology*
chemical_list: D013004:Somatostatin; D013656:Taurocholic Acid; D001285:Atropine; D002927:Cimetidine; D006632:Histamine; D002217:Carbachol