Axonal transport of noradrenaline and noradrenergic transmission in rats with streptozotocin-induced diabetes.

The accumulation of noradrenaline in constricted sciatic nerves was measured in 6 month diabetic rats (streptozotocin 35 mg/kg) and 4 day diabetic rats (streptozotocin 70 mg/kg) together with two groups of age-matched control animals. There was no alteration in the amount of noradrenaline accumulated in the nerves of the diabetic animals when compared with the controls. The vasa deferentia of the long-term diabetic animals showed an impaired response to stimulation of their noradrenergic nerves and a hypersensitivity to exogenous noradrenaline. These vasa were not wasted and showed a normal contractility in response to potassium chloride. Vasa deferentia from the short-term diabetic rats showed no abnormalities of function. Vasa deferentia from all groups of rats were also examined at the ultrastructural level. Specimens from all the chronically diabetic animals contained many abnormal nerve terminals. These lesions were not seen in vasa from the short-term diabetic rats. Taken together these findings indicate that rats with chronic streptozotocin-induced diabetes exhibit pathological changes in the noradrenergic nerves supplying the vas deferens. These animals do not, however, show an impairment of the axonal transport of noradrenaline.