alpha-Adrenergic regulation of secretion of mouse saliva rich in nerve growth factor

Nerve growth factor has been quantified by both bioassay and radial immunodiffusion in mouse saliva elicited by several secretagogues. The concentrations by bioassay of nerve growth factor in both epinephrine- and norepinephrine-induced saliva (3400 and 900 mug/ml, respectively) are higher than reported in any other source. In contrast, the concentrations of nerve growth factor in isoproterenol- and pilocarpine-induced saliva are relatively low (17 and 2 mug/ml, respectively). The specific activity of the salivary nerve growth factor was 41, 36, 2, and 0.6 mug/mg of protein in secretions elicited by epinephrine, norepinephrine, pilocarpine, and isoproterenol, respectively. Salivation after administration of either epinephrine or norepinephrine was completely inhibited by the alpha-adrenergic blocker, phenoxybenzamine. These results suggest that the release of saliva rich in nerve growth factor is primarily regulated through alpha-adrenergic receptors.