Orexin-A对肥胖大鼠弓状核葡萄糖敏感神经元影响

EFFECTS OF OREXIN-A ON GLUCOSE-SENSITIVE NEURONS IN THE ARCUATE NUCLEUS OF OBESE RATS

目的观察orexin-A对正常大鼠和肥胖大鼠弓状核(Arc)葡萄糖敏感(GS)神经元放电活动的影响。方法高脂饮食诱导肥胖大鼠,观察orexin-A对正常大鼠和肥胖大鼠Arc GS神经元放电活动的作用,并比较两组大鼠orexin-A作用的差异。结果 Arc注射生理盐水,正常大鼠和肥胖大鼠GS神经元的放电频率均无显著改变(P>0.05)。Arc注射orexin-A后,正常大鼠葡萄糖兴奋型(GE)神经元放电频率降低(t=10.93,P<0.05),葡萄糖抑制型(GI)神经元放电频率升高(t=10.84,P<0.05);注射orexin-A+SB-334867后,orexin-A对正常大鼠GI神经元的兴奋作用和GE神经元的抑制作用消失(P>0.05)。Arc注射orexin-A后肥胖大鼠GE神经元放电频率降低(t=11.50,P<0.05),GI神经元放电频率升高(t=11.17,P<0.05);注射orexin-A+SB-334867后,orexin-A对肥胖大鼠GS神经元的作用消失(P>0.05)。与正常大鼠比较,orexin-A对肥胖大鼠Arc GS神经元的作用显著增加(t=11.38、11.13,P<0.05)。结论 Orexin-A可以影响Arc GS神经元的放电活动,且在肥胖大鼠中的作用更显著。

Objective To investigate the effects of orexin-A on the discharge of glucose-sensitive（GS）neurons in the arcuate nucleus（Arc）of normal and obese rats. Methods Obese rats were induced by high-fat diet.The effects of orexin-A on the discharge of GS neurons in the Arc were observed and compared between the normal rats（normal group）and the obese rats（obese group）. Results Both groups had no significant change in the discharge frequency of GS neurons in the Arc after the injection of normal saline into the Arc（P〉0.05）.After the injection of orexin-A into the Arc,the normal group and the obese group had a significant decrease in the discharge frequency of glucose-excited（GE）neurons（t=10.93,11.50;P〈0.05）and a significant increase in the discharge frequency of glucose-inhibited（GI）neurons（t=10.84,11.17;P〈0.05）;however,after the injection of orexinA＋SB-334867 into the Arc,the above effects of orexin-A on GS neurons were not observed in both groups（P〉0.05）.Compared with the normal group,the effects of orexin-A on GS neurons in the Arc were increased significantly in the obese group（t=11.38,11.13;P〈0.05）. Conclusion Orexin-A can affect the discharge of GS neurons in the Arc and the effect is increased significantly in obese rats compared with normal rats.