Muscarinic and alpha-adrenergic stimulation of Na and Ca uptake by dispersed lacrimal cells.

Rat lacrimal gland acinar cells were isolated and observed to be physiologically stable for several hours of incubation in vitro. With a double-isotope technique, it was found that carbachol and epinephrine stimulated the uptake of 22Na and 45Ca by lacrimal cells. These respnses were maximal at agonist concentrations of 10(-5) M and were blocked by atropine and phentolamine, respectively. It is concluded that muscarinic and alpha-adrenergic receptor activation increase the membrane permeability of the lacrimal gland acinar cell to Na and Ca, ions that may be important in the secretion of water by the lacrimal gland.