Lack of Sympathetic Augmentation in Response to Intravenous Load of Glucose in Rabbits

We investigated a link between sympathetic nervous function and carbohydrate metabolism by measuring renal sympathetic nerve activity in response to intravenous load of glucose in alpha-chloralose-urethane anaesthetized rabbits. 2. Intravenous infusion of a 25% glucose solution (0.5 g/kg) over 3 min caused a transient increase in arterial blood pressure and a decrease in renal sympathetic nerve activity. Thereafter, these parameters were restored and remained around preload levels while plasma glucose and insulin concentrations were still elevated. 3. Equimolar mannitol solution produced similar patterns of change in blood pressure and nerve activity without an elevation of plasma glucose and insulin levels. 4. The transient changes in blood pressure and renal nerve activity could be attributed to acute hypervolaemia indicated by similar changes in plasma osmolality and haematocrits in the two groups of treatment. 5. The present study did not support a close relationship between carbohydrate metabolism and the sympathetic nervous system regulating cardiovascular function.