Chloride Concentration of Rat Parotid Saliva Evoked by Electrical Stimulation of Parasympathetic or Sympathetic Nerves with or Without Antagonists

Abstract

Abstract

Chloride (Cl) of saliva evoked by electrical stimulation of the parasympathetic nerve to parotid gland was from two to seven times higher than that elicited with sympathetic nerve stimulation; [Cl] remained elevated (125–135 mEq/liter) for 60 min of parasympathetic nerve stimulation, whereas Cl of sympathetically evoked saliva decreased from high levels of 58 to 15 to 20 mEq/liter. The administration of propranolol, the β-adrenergic antagonist, 20 min prior to initiation of sympathetic nerve stimulation resulted in saliva with Cl of 100 mEq/liter; when phentolamine, the α-adrenergic antagonist was administered prior to sympathetic nerve stimulation, [Cl] was 48–35 mEq/liter. Values with the β-agonist, isoproterenol, were about 35 mEq/liter, whereas phenylephrine, an α-adrenergic agonist, evoked saliva with Cl ranging from 113 to 85 mEq/liter. Flow rate was very high with parasympathetic nerve stimulation and low with sympathetic nerve stimulation, but [Cl] with β-blockade was not flow dependent: flow was very low but Cl high. Cl secretion is principally regulated by activation of cholinergic and α-adrenergic receptors.