Acid secretion of parietal cells is paralleled by a redistribution of NSF and alpha,beta-SNAPs and inhibited by tetanus toxin

Stimulation of parietal cells causes fusion of intracellular tubulovesicles with the canalicular plasma membrane thereby increasing the apical membran e area up to tenfold. The presence of the SNARE proteins synaptobrevin, syn taxin1, and SNAP25 in parietal cells and their intracellular redistribution after stimulation suggest a SNARE-mediated mechanism. Here we show that NS F and alpha, beta -SNAPs which are involved in the dissociation of the SNAR E complex in neurons also occur in parietal cells exhibiting subcellular di stributions similar to the ones obtained for SNARE proteins and for the H+, K+-ATPase. More importantly proteolytic cleavage of synaptobrevin by tetan us neurotoxin completely inhibits the cAMP-dependent increase of acid secre tion further supporting the crucial role SNARE proteins play in parietal ce lls.