A study of parotid salivation in the horse

Abstract

Saliva flowed from the horse''s parotid duct only during mastication. The surface-active local anesthetic administered by mouth inhibited salivary secretion. Salivary secretion was stimulated by pilocarpine and inhibited by atro-pine. The volume and composition of saliva secreted in 24 hr from one parotid duct was determined. The concentration of Na, K, Ca, Cl and HCO2 depended upon the rate of flow. The highest concentrations of these electrolytes were observed during periods of high flow rates. Horse parotid saliva contained a high concentration of Ca. In the absence of a dietary supplement of sodium bicarbonate, the Na concentration of the saliva fell after about 21 das. There was an associated increase in the K concentration. The addition of a Na supplement restored the Na concentration of the saliva within 24 hr.