Fluid and protein secretion from ferret submandibular and parotid glands in response to sympathetic nerve stimulation or administration of sympathomimetics.

Abstract

Electrical stimulation of the sympathetic innervation evoked secretion of submandibular and parotid saliva. By changing the mode of stimulation from a continuous to an intermittent one the fluid response increased and glandular blood flow improved. The volumes from the submandibular glands were larger than those from the parotid glands and further, the protein concentration of submandibular saliva was higher than that of parotid saliva. Adrenaline, isoprenaline and phenylephrine evoked larger fluid responses from submandibular than from parotid glands. However, the fluid response was small compared to the parasympathetic one. Substance P-evoked saliva was used as carrier for protein released by sympathetic nerve stimulation or administration of adrenaline and isoprenaline. In vitro tissues of submandibular and parotid glands responded to adrenaline with a dose-dependent release of protein. Taken together, the analytical pharmacology performed in vivo and in vitro, and including the antagonists phentolamine, dihydroergotamine, propranolol and metoprolol, showed that in submandibular glands, alpha(alpha 1)adrenoceptors were predominantly involved in fluid secretion and beta(beta 1)-adrenoceptors predominantly involved in protein secretion. In parotid glands, fluid secretion seemed solely to depend on alpha(alpha 1)-adrenoceptors, while beta(beta 1)-adrenoceptors seemed almost solely involved in protein secretion.