IN-VIVO SECRETORY RESPONSES OF SUBMANDIBULAR GLANDS IN STREPTOZOTOCIN-DIABETIC RATS TO SYMPATHETIC AND PARASYMPATHETIC NERVE-STIMULATION

Submandibular gland responses to sympathetic and parasympathetic nerve stimulation were studied in streptozotocin-diabetic rats. Morphologic ally, the acinar cells in control glands were relatively uniform in si ze and contained electron-lucent granules. The granular ducts were dis tinguished by the presence of electron-dense granules. With the except ion of intracellular lipid droplets and the presence of a few autophag osomes in diabetic glands, no consistent differences in acinar cell st ructure were observed. In contrast, the diameter of the granular ducts and the granule content of their cells were less in diabetic glands. At 3 weeks sympathetic flow rate, salivary protein concentration, and total protein output were unaffected by diabetes. Sympathetic flow rat e was greater at 3 months, and the concentration of protein in the sal iva was lower. In 6-month diabetic rats flow rate remained increased, but protein concentration and total protein output were reduced. The d ecrease in salivary protein concentration at 3 and 6 months was accomp anied by a reduction in secretory granule release from acinar and gran ular duct cells. No consistent differences in flow rate, protein conce ntration, protein output, or secretory granule release were observed f ollowing parasympathetic stimulation. We conclude that the effects of diabetes on nerve-stimulated flow rate and protein release depend on t he duration of diabetes and the type of stimulation, and are independe nt of one another.