Role of cyclic GMP in submandibular gland secretion.

Cholinergic stimulation of rat submandibular gland slices resulted in a rapid increase in the level of cyclic GMP. This increase was dependent upon the presence of Ca2+ and a phosphodiesterase inhibitor. Adrenergic agonists did not produce a significant elevation of cyclic GMP. The addition of Ca2+ to slices preincubated with the divalent ionophore A23187 caused a rapid rise in cyclic GMP levels which were unaffected by cholinergic stimulation. While these results could support a function for cyclic GMP in cholinergic-mediated K+-release from these glands, they do not support a role for this nucleotide in alpha-adrenergic agonist-induced K+-release or protease secretion.