Parasympathetic control of Na, K transport in perfused submaxillary duct of the rat.

The effects of stimulating the parasympathetic innervation to rat submaxillary gland on ductal transport of Na, K, water, and transepithelial PD, were tested in the main excretory duct during perfusion through its lumen. During nerve stimulation, transepithelial PD was consistently decreased, usually by about 15 mV, and this decrease could be blocked by atropine but not by adrenergic blocking agents. Net flux of Na, K, or water was not significantly changed during stimulation. One-way flux of Na from the lumen also was unaffected. The decrease in PD during stimulation was not affected by substituting isethionate for Cl or increasing [K] in the luminal perfusion medium. It is concluded that parasympathetic effects are exerted on the ductal cells, but that these probably do not involve conductance changes at the luminal membrane.