PHYSIOLOGICAL REGULATION OF THE SECRETION OF HISTATINS AND STATHERINSIN HUMAN PAROTID-SALIVA

The small salivary phosphoproteins, histatins and statherins, have imp ortant functions in the oral cavity in terms of antimicrobial actions and regulation of calcium phosphate homeostasis. Neither the effects o f various physiological stimuli on their secretidon nor the nature of the efferent receptor involved in the stimulus-secretion coupling has been determined previously. These aspects are important for improved u nderstanding of the secretory control of salivary proteins and may hav e implications regarding the effects of specific medications on saliva ry constituents and oral health. The effects of graded mechanical (che wing on short and long silicone tubings) and gustatory stimulation (0. 5, 1.5, and 5.0% citric acid) on the secretion of histatins and stathe rins were studied in the presence and absence of adrenolytic agents (n = 10). In this model, secretory rates of both proteins increased with increases in flow rate, with 5.0% citric acid representing a particul arly potent stimulus. Histatin and statherin secretory rates were sign ificantly reduced by the beta(1)-adrenolytic agent (histatins to 58 to 72% and statherins to 11 to 29% of that in corresponding control expe riments), but not by the alpha(1)-adrenolytic agent. Since the beta(1) -adrenergic receptors played an important role in the stimulus-secreti on coupling of these proteins, protective salivary functions in the or al cavity may be compromised during beta(1)-adrenolytic treatment.