Estazolam逆转结节乳头体核组胺引发的觉醒

Estazolam reverses histamine in tuberomammillary nucleus induced arousal effect

目的观察增加γ-氨基丁酸(gamma-aminobutyricacid,GABA)受体与GABA亲和力的Estazolam对结节乳头体核(tuberomammillary nucleus,TMn)组胺(histamine,HA)产生觉醒的作用,探究GABA与TMn的HA对睡眠-觉醒周期的调节。方法♂SD大鼠随机分为对照组,生理盐水组,Estazolam组,HA组,以及HA+Estazolam(2.5mg)组,HA+Estazolam(5mg)组。颅骨和颈肌植入脑电图(EEG)和肌电图(EMG)电极,带芯的不锈钢导管植入TMn邻近区以备微量注射药物。术后恢复7d,各组分别记录24h的EEG和EMG,分析睡眠-觉醒周期中各时相的变化。结果:TMn内注射HA(1μg.kg-1)在24h中觉醒时间增加(P<0.01),慢波睡眠被抑制,但不影响异相睡眠(paradoxicalsleep,PS)。灌胃给予Estazolam(5mg.kg-1)产生以深度慢波睡眠(SWS2)增加(P<0.01)为主要特征的总睡眠时间增加。在HA引起的觉醒达高峰(2h)的时候分别灌胃给予Estazolam2.5mg.kg-1与5mg.kg-1,使觉醒转为睡眠,并呈剂量依赖性。结论TMn内HA能神经元促进和维持觉醒,作用于GABA神经元末梢的苯二氮类(benzodiazepine,BZD)1受体的Estazolam,通过增加SWS2而增加总睡眠时间,并逆转HA引起的觉醒状态。

Aim The effect of Estazolam, a potential agonist for promoting gamma-aminobutyric acid （GABA） release, on histamine （HA） in tuberomammillary nucleus （TMn） induced arousal activity was investigated. The interaction between TMn histaminergic and GABAergic neurons for modulating sleep-wakefulness cycle was further studied. Methods 30 male Sprague-Dawley rats were randomly divided into 6 groups： control group, saline group, Estazolam group, HA group, HA ＋ Estazolam （2.5 mg · kg^-1） group, HA ＋ Estazolam （5 mg · kg^- 1 ） group. Four stainless steel screw electrodes （2 mm in diameter） were implantedinto the skull to the surface of the cerebral dura mater for recording EEG. Two silver wire electrodes were inserted bilaterally into the dorsal neck muscles for recording EMG. The stainless steel guide cannular （0. 06 mm in diameter） was implanted into the adja- cent of TMn for subsequent drug microinjection. After 7 d recovery, a basic sleep-wake cycle as control of EEG and EMG was recorded and every phase analyzed for 24 h. The wake and sleep states including light slow wave sleep （SWS1）, deep slow wave sleep （ SWS2 ） and paradoxical sleep （PS） were statistically calculated per 1 0 s epochs for 2 4 h , when saline anddrugs were subsequently administrated according to protocol. Results Microinjection HA （ 1 μg· kg^-1 ） into TMn increased the durational time of wake （ P 〈 0.01 ） and reduced the SWS time, but did not have effect on PS compared to saline microinjeetion into TMn for 24 h. Estazolam （5 mg· kg ^- 1, po） increased the total sleep time via increase of SWS2 （ P 〈 0.01 ） without SWS1 and PS time compared to control, and also reversed the HA-induced wakefulness into sleep（P 〈 0.01 ）. Conclusions Histaminergic neurons in the TMn play a key role in promoting and maintaining the wakefulness. Estazolam induces an increase of the total sleep time mainly through increasing SWS2, and reverses HA-induced wakefulness into sleep.