The intracellular pH (pHi) of rat submandibular cells was measured by 2', 7'-bis (carboxyethyl)-5 (6)-carboxyfluorescein (BCECF). The cells recovered from ammonium (30 mM) prepulse to their resting pHi within 10 min. Ethylisopropylamiloride (EIPA), an inhibitor of the Na+/H+ exchanger, slows the rate of pHi recovery. ATP (1 mM), in the presence of EIPA, increases the rate of recovery 3.7-fold in the absence or presence of ethylene glycol-bis (beta-aminoethyl ether)-N, N, N', N'-tetraacetic acid. The recovery was blocked by the addition of 5 mM Mg2+ or 10 microM Coomassie blue. The response was elicited by 2'-and 3'-O-(4-benzoylbenzoyl)-adenosine 5'-triphosphate but not by ADP, UTP, adenyl (beta-gamma-methylene)-diphosphonate, 2-methylthioadenosine 5'-triphosphate, or muscarinic or beta-adrenergic agonists. The purinergic response was also observed when the cells …