SODIUM AND CHLORIDE TRANSPORT ACROSS THE RUMEN EPITHELIUM OF CATTLE IN-VITRO - EFFECT OF SHORT-CHAIN FATTY-ACIDS AND AMILORIDE

Isolated mucosal sheets of cattle rumen were studied in vitro in Ussin g chambers using a computer-controlled voltage clamp. Unidirectional f luxes of Na+ and Cl- were measured in standard (short-chain fatty acid (SCFA)-free) or SCFA-containing Ringer solution under zero voltage cl amp conditions. Net NaCl absorption was observed under zero voltage cl amp conditions, was stimulated by SCFAs and was not reduced by 1 mmol l(-1) amiloride, although short-circuit current was significantly redu ced by this concentration of the blocker. A constant coupling ratio of Na+ and Cl- absorption was observed.