The Cytosolic Acidification in Rat Parotid Cells Is Associated with an Increase in Cytosolic Ca²⁺ Concentration

Abstract

A transient decrease in cytosolic pH ([pH]_i)in rat parotid cells was evoked by the addition of carbachol (CCh), phenylephrine, or substance P, whereas isoproterenol and dibutyryl cyclic AMP had little or no effect on [pH]_i. The decrease in [pH]_i induced by the Ca²⁺-mobilizing agonists was also observed in Ca²⁺-free medium, but not when the intracellular Ca²⁺ stores were previously depleted. lonomycin and thapsigargin elicited a decrease in [pH]_i with an increase in cytosolic Ca²⁺ concentration ([Ca²⁺]_i). The protein kinase C activator and inhibitor had no effect on the agonist-induced decrease in [pH]_{i. These results suggest that the cytosolic acidification is associated with an increase in [Ca²⁺]i.}