Autonomic receptors and cyclic nucleotides of rat parotid gland following simultaneous electrical stimulation of its parasympathetic and sympathetic nerves.

[3H]dihydroalprenolol and [3H]quinuclidinylbenzilate binding of membranes of rat parotid gland were generally unchanged after 10, 15, 30, or 60 min of simultaneous electrical stimulation of the parasympathetic and sympathetic nerves to the gland, although stimulation of either nerve separately caused nerve-specific changes in both. Concentrations of cyclic nucleotides of the gland were, however, increased significantly from levels of the unstimulated parotid gland. Cyclic GMP showed a 10-fold increase after 10 min of stimulation, whereas only a 2-fold increase in cyclic AMP was found at this time. The increases were maintained, albeit at reduced levels, at 15 and 30 min also but by 60 min both were not different from levels of the unstimulated gland. The increases induced by separate stimulation of each nerve were greater but nerve specific, and the changes induced with simultaneous stimulation tended to reflect a reigning influence of one nerve on the other.