Effects of short-term (2 weeks) streptozotocin-induced diabetes on acetylcholine and noradrenaline in the salivary glands and secretory responses to cholinergic and adrenergic sialogogues in mice

Acetylcholine and noradrenaline concentrations in the submandibular, parotid and sublingual glands, and pilocarpine-, isoproterenol- and phenylephrine-induced salivation, were estimated in streptozotocin (STZ)-induced diabetic mice. Diabetic mice showed significant increases in acetylcholine and noradrenaline (expressed as nmol/gland) in sublingual and submandibular glands, respectively. The total volume of crude whole saliva in diabetic mice in response to pilocarpine and isoproterenol but not to phenylephrine was significantly reduced. These results suggest that alterations in the neurotransmitter levels and secretory function in the salivary glands occur rapidly after the induction of STZ diabetes, and that the secretory function appears to be more susceptible to effects of diabetes in the early stages than the autonomic nervous system. Since the alterations in neurotransmitter concentrations in diabetic salivary glands were slight and partial, it seems that they are unrelated to the markedly reduced salivation in response to pilocarpine and isoproterenol observed in these short-term diabetic mice.