ULTRASTRUCTURAL AND CYTOCHEMICAL ANALYSIS OF NA-CELLS OF GASTRIC-MUCOSA IN THE RABBIT(, K+, ATPASE AND H+, K+, ATPASE IN PARIETAL)

Rabbit gastric secretion has the physiological peculiarity of being co ntinuous and uninfluenced by food intake. In this respect, ultrastruct ural analysis of rabbit parietal cells has revealed morphofunctional f eatures situated between states of rest and very active acid secretion . Our cytochemical study shows that Mg2+ ATPase and ADPase activities vary from cell to cell and can even be totally absent. These activitie s concern either microcanaliculi or laterobasal folds or both, but nev er tubulovesicles. Application of the technique of Mayahara to K+ pNPP , associated or not with inhibitors (ouabain, vanadate, N-ethyl-maleim ide, sodium fluoride), enabled us to confirm the coexistence of H+, K, ATPase and Na+, K+, ATPase activities in the rabbit and to determine that these activities concern basolateral folds, microcanaliculi, hya loplasm and tubulovesicles. The global activity of K+, pNPPase varied considerably in intensity. The results of using inhibitors suggest tha t proton transport ceases completely in certain cells. The signs of fu nctional alternation found in this study are in agreement with physiol ogical data relative to this animal.