Electrophysiological effects of substance P and VIP in the denervated rat parotid gland.

The effects of SP and VIP were studied in vitro in normal and denervated parotid glands of the rat using electrophysiological techniques. After sympathetic, and especially after parasympathetic, denervation the number of cells responding to peptides increased significantly. Furthermore, sub-threshold doses for control glands induced membrane potential changes after denervation. It seems reasonable to correlate these findings to the development of supersensitivity. The underlying mechanisms, however, require further investigation.