下丘脑Hypocretin神经肽在大鼠缰核对睡眠-觉醒调节中的作用

Effect of Hypocretin neuropeptide in hypothalamus participating in regulation of habenular nucleus on sleep-wakeness process

目的:研究下丘脑Hypocretin神经肽在缰核(Hb)对睡眠-觉醒调节中的作用,为探讨Hb在睡眠-觉醒调节中的作用提供理论依据。方法:成年雄性Wistar大鼠20只,随机分为实验组(n=10)和对照组(n=10),实验组灌胃给予催眠药唑吡坦5mg.kg-1,对照组给予等量生理盐水,待唑吡坦药效达峰值时,将大鼠断头处死,取出Hb组织,提取总RNA,采用逆转录聚合酶链反应(RT-PCR)检测Hb中HcrtR2 mRNA的表达水平。另取大鼠(n=5)单侧Hb微量注射霍乱毒素b亚单位(CTb),采用CTb逆行追踪法观察下丘脑内是否有免疫阳性神经元存在。结果:经RT-PCR检测,实验组和对照组Hb中HcrtR2 mRNA的表达水平(相对平均灰度值分别为0.13±0.03和0.26±0.04)比较差异有显著性(P<0.05)。免疫组织化学染色显示,在大鼠下丘脑外侧区(LHA)、外侧视前区(LPO)和弓状核(ARC)都可见CTb标记免疫阳性神经元。结论:下丘脑Hypocretin神经肽及其受体参与Hb对睡眠-觉醒调节的作用,且Hb接受下丘脑内睡眠相关结构LHA、LPO、ARC的纤维投射。

Objective To study the effect of Hypocretin neuropeptide in hypothalamic nuclei participating in regulation of habenular nucleus （Hb） on sleep-wakeness process and to provid theoretical basis for it. Methods Zolpidem （5mg·kg^-1） and saline were administered respectively to adult wistar rats by gavage in experimental group （n=10） and control group （n=10） and the Hb tissue was extracted when the drug action was at peak. The expression of HcrtR2 mRNA of Hb was determined by using RT-PCR technique. Choleratoxin B solution was microinjected into the isolateral Hb of rats （n=5） to retrograde and observe whether labelled cells existed in hypothalumic nuclei. Results The expression of HcrtR2 mRNA in the Hb of experimental group （0.13±0.03） was lower than that of control group （0.26±0.04, P〈0.05）. The choleratoxin B labelled cells distributed in the lateral hypothalamic area, the lateral preoptic area and the arcuate nucleus. Conclusion Hypocretin neuronpeptide in hypothalamic nuclei and its receptor are involved in the regulation of the Hb on sleep-wakeness process. The Hb is innerved by the lateral hypothalamic area, the lateral preoptic area and the arcuate nucleus.