Beta-adrenoceptor stimulation increases the pH of parotid acinar cells

To characterize the effect of L-norepinephrine on intracellular pH (pHi) in parotid acinar cells, were measured the accumulation of 14C-labelled 5,5-dimethyloxazolidine-2,4-dione ([14C]DMO), in slices of parotid glands from Sprague-Dawley rats. L-Norepinephrine enhanced the [14C]DMO uptake in a concentration-dependent manner with half-maximal effect at about 1 microM and maximum effect at about 1 mM. The half-maximal effect corresponded to an increase in pHi by 0.08 units and was reduced by 2 microM L-propranolol (beta-adrenoceptor antagonist), but was not affected by 2 microM phentolamine (alpha-adrenoceptor antagonist). The results suggest that L-norepinephrine increases intracellular pH in rat parotid acini and that this effect may be mediated by beta-adrenoceptor stimulation.