Reduction of secretory responses of salivary glands to cholinergic and adrenergic silogogues in rats in early stages of diabetes mellitus

ABSTRACT

A dry mouth caused by decreased salivary secretion is a common complication in human diabetes mellitus. Diabetes was induced in rats using two different pancreatic Beta-cells toxins, streptozotocin [STZ] and alloxan. Two weeks after induction of diabetes, pilocarpine-, isoproterenol-, and phenylephrine-induced salivary secretion were estimated and compared to control normal rats. Diabetic rats showed significant decrease in the total volume of crude saliva in response to pilocarpine and isoproterenol but not to phenylephrine. Correction of the diabetic condition by giving insulin subcutaneously resulted in significant improvement of salivary glands response to sialogogues. Taken together, these results suggest that salivary glands dysfunction that occurs early in diabetes is probably due to metabolic deterioration in the acinar cells due to insulin insufficiency, rather than due to developing autonomic neuropathy that may affect salivary glands function in long-term diabetes