The effects of electrical stimulation of the autonomic nerves and of drugs on the size of salivary glands and their rate of cell division.

The effects of electrical stimulation of the sympathetic and of the parasympathetic nerves on the size of rat salivary glands have been investigated and compared with those caused by isoproterenol. Sympathetic nerve stimulation increased the size and the mitotic index in the parotid acini; in the submaxillary acini, only the size was increased. These responses varied with the gland studied and the duration of stimulation; the parotid showed the larger increase in the mitotic index and thymidine uptake, the submaxillary the greater degree of cell enlargement. Prolonged electrical stimulation beyond that required to produce the maximum increase in size reduced the enlargement. Sympathetic nerve stimulation caused no enlargement in the extraorbital lacrimal or major sublingual glands. The responses to sympathetic nerve stimulation were inhibited by propranolol (17 nmol/pg), normetanephrine (2 X 45 nmol/g) and mecamylamine (50 nmol/g) but not by phentolamine (13.0 nmol/g) or atropine (7.5 nmol/g). Electric stimulation of the parasympathetic nerves produced no increase in the size or in the mitotic index.