Centrally injected atropine reduces hyperglycemia caused by 2-DG or immobilization stress in awake rats

Abstract

The physiological significance of central cholinergic neurons was investigated by verifying the effect of previous intracerebroventricular administration of atropine on the hyperglycemia induced by 2-deoxyglucose (2-DG) or by immobilization stress in unrestrained, nonanesthetized rats. Intravenous 2-DG induced a marked increase in plasma glucose that was not affected by atropine injected intracerebroventricularly 30 min before. However, the hyperglycemia induced by intracerebroventricular 2-DG was significantly reduced by previous intracerebroventricular injection of atropine. Immobilization induced a rapid increase of plasma glucose levels that was reduced by about 50% by intracerebroventricular injection of atropine. The increase in plasma lactate induced by intravenous 2-DG, or immobilization, was not significantly affected by previous intracerebroventricular injection of atropine. The data suggest that central cholinergic neurons participate in the complex neural events responsible for the hyperglycemic response to neurocytoglucopenia and to stressful situations.