CNS INVOLVEMENT IN THE GLUCOSE-INDUCED INCREASE OF ISLET BLOOD-FLOW IN OBESE ZUCKER RATS

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 inj ected 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 i nsulin level and islet blood flow without a significant change in plas ma glucose concentration in both lean and obese rats. Prior vagotomy o r clonidine injection resulted in a decrease in glucose-induced islet blood flow. Both the effect of glucose and its reversal were more pron ounced in obese rats. CONCLUSION: In obese rats, an alteration of the CNS could result in an increase in the parasympathetic tone and a decr ease in the sympathetic one. These alterations would in turn contribut e to the modifications in islet blood flow.