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 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.