Objectives: The aim of this work was to study the role of the central nervous system in the glucose-induced increase in islet blood flow in obese Zucker rats.
Design: A small amount of glucose (9 mg/kg) was injected towards the brain via the left carotid artery in lean obese rats either intact or vagotomized and after a pretreatment with clonidine.
Results: Glucose injection induced a significant increase in plasma insulin level and islet blood flow without a significant change in plasma glucose concentration in both lean and obese rats. Prior vagotomy or clonidine injection resulted in a decrease in glucose-induced islet blood flow. Both the effect of glucose and its reversal were more pronounced in obese rats.
Conclusion: In obese rats, an alteration of the CNS could result in an increase in the parasympathetic tone and a decrease in the sympathetic one. These alterations would in turn contribute to the modifications in islet blood flow.