中国图书资料分类法分类号R338.63
Pharmacological study of slow wave sleep
KU Bao-Shan
(Department of Pharmacology, Beijing Medical University, Beijing100083)
MeSHSlow wave sleep☆Sleep/drug effHypnotics and sedatives/pharmacolInsomnia/drug ther
ABSTRACT There are three sleeping stages: light sleep, slow wave sleep (SWS)and rapid eye movement sleep(REM sleep). A hypothesis is presented: SWS is the most important one in the sleeping stages. The most important hypnotics will be the drugs selectively promoting SWS. The drugs will be improving insomnia, helping the treatment of anxiety, depression and dementia. The recent decade advances on sleep regulation include the following: (1)Ventrolateral preoptic area-tuberomammillary nucleus (VLPO-TMN) seems to generate sleep and wakefulness . The rostral basal forebrain, which was sensitive to pGD2, may be involved in regulating sleep. (2)Growth hormone releasing hormone (GHRH), melatonin, prostaglandin D2(pGD2), IL-1 and adenosine could increase the SWS. Our studies on SWS include the following: (1)Setup the auto-analysis sleeping stages systems (ASS)for rabbits and rats. (2)With the ASS the effects of immune-enhancing substances were studied such as transfer factor, muramyl dipeptide and TNF on sleeping stages in rabbits and the effects of 5-HT1A receptor agonist and 5-HT2 receptor antagonist on sleeping stages in rats. (3)Researched the relationship between 5-HT1A receptor, depriving REM sleep and 5-HT2 receptor. The recent advances on sleep regulation proved feasibility and validity of the hypothesis. Our results showed the approach: the immune enhancing -TNF increasing -5-HT turnover increasing -SWS. The result of stimulating 5-HT1A receptor was similar to that of antagonizing 5-HT2 receptor, and showedsynergistic effects with the both. The development of new type of hypnotics, which selectively prolong SWS, might consider the following clues : pGD2stimulators, adenosine receptor agonists, immune-enhancing substances, some hormones and agents influencing 5-HT2 subreceptors.
(J Beijing Med Univ, 1999,31:204-208)
1催眠药物开发构想的提出
睡眠是一种最基本的生理行为,也是保障身心健康的最重要条件,睡眠障碍是常见的疾病和多种疾病伴随症状。睡眠有3种主要成分:浅睡眠、深睡眠又叫慢波睡眠(slow wave sleep, SWS)和快眼动睡眠(rapid eye movement sleep,REM sleep)。研究有关文献发现下述重要现象:脑发育成熟后REM睡眠在睡眠中所占比例比较固定(20%左右),具有不可压缩性,人为减少后(催眠药或剥夺睡眠)会引起强烈“反跳”,其功能与大脑白天获得信息的处理、学习记忆、躯体休息和性功能发育有关。SWS是大脑皮层睡眠(高幅慢波),期间生长激素分泌达最高峰;正常短睡眠者(4~5 h)和普通人(8 h)最大区别在于前者SWS所占比例明显增加(前者40%,后者20%左右);如果剥夺正常青年人3 d睡眠,恢复自由睡眠后的第一夜主要是SWS“反跳”,第二夜则主要是REM睡眠“反跳”,浅睡眠总量增加并不明显;某些重症神经精神疾病如早老性痴呆、重症焦虑和抑郁症,SWS明显减少甚至完全消失。浅睡眠的重要性则远不及SWS和REM睡眠。
镇静催眠药和抗焦虑药是应用最多的药物,作用特点在于使失眠者入睡快,浅睡眠时间明显延长,中间不易醒,但都(95%以上)程度不同地缩短了SWS和REM睡眠。据此,作者于1991年率先提出“催眠药物开发新构想”,即主张开发选择性增加SWS、同时能够保证REM睡眠正常比例的药物,因为这种催眠药物可以更有效地改善睡眠,并且有可能辅助治疗焦虑症、抑郁症和老年痴呆。此构想见文献[1]。
2近十年来SWS研究进展
自提出“催眠药开发新构想”后,十分关注SWS研究动态。首先有两个药物,丁螺环酮(buspirone, 5-HT1A受体部分激动剂)和利坦色林(ritanserin, 选择性5-HT2受体拮抗剂),可以增加SWS,临床上用来治疗抑郁症和焦虑症[2]。Sherin等[3]联合应用逆向示踪剂霍乱毒素B和Fos免疫组化技术,证明腹外侧视前区(ventrolateral preoptic area, VLPO)对结节乳头核(tuberomammillary nucleus, TMN)通过γ-氨基丁酸(gamma-aminobutyric acid, GABA)能神经起抑制作用,而TMN参与上行觉醒系统。Scammell等[4]在基底前脑吻端的蛛网膜下腔内灌注前列腺素D2(prostaglandin D2,pGD2)后,SWS睡眠明显增加,同时VLPO有强烈Fos表达。那么,从pGD2激动软脑膜上的受体到VLPO神经元活动增强之间信号传导是怎样的呢?Satoh等[5]以选择性腺苷A2受体激动剂CGS21680和拮抗剂KF17837为工具研究证实,pGD2受体激动后通过诱导软脑膜细胞分泌腺苷来激动邻近的VLPO神经元,抑制TMN觉醒系统,诱发和促进SWS。睡眠与夜间激素分泌之间存在明显相关性,睡眠早期SWS占优势,此时下丘脑-垂体-肾上腺皮质(hypothalamus pituitary adrenal, HPA)轴分泌活动显著低下,生长激素分泌最活跃;睡眠后期则REM睡眠占优势,此时HPA轴分泌最活跃,生长激素分泌低下。研究证明生长激素释放激素(growth hormone releasing hormone, GHRH)和促肾上腺皮质激素释放因子(corticotrop releasing factor, CRF)之间的平衡在睡眠调节中发挥着重要作用,给予GHRH增加SWS,给予CRF则减少SWS[6]。直接影响睡眠的激素是褪黑激素(melatonin),正常情况下它主要调节睡眠时相,在失眠状态下外源性给予褪黑激素可起催眠作用。值得注意的是β肾上腺素受体阻断剂明显减少褪黑激素的分泌(松果体受交感神经支配,突触后膜为β受体),造成入睡困难、REM睡眠和SWS减少及觉醒次数增加,给予melatonin可使之恢复到正常水平[7]。细胞因子中除早已证明的TNF外,IL-1促进SWS效应倍受重视,而且与pGs有关,在pGD2敏感的基底前脑吻端的蛛网膜下腔灌流IL-1使SWS增加,环氧酶抑制剂双氯芬酸(diclofenac)可以阻断这种效应[8]。
3为实现“构想”所进行的研究工作
3.1建立睡眠成分自动分析系统
此前,国内研究药物的镇静催眠作用,主要采用的实验方法是观察给药后动物(大鼠或小鼠)自主活动是否减少,能否增强戊巴比妥钠在动物的麻醉作用。少见药物对于睡眠成分影响的研究报道。究其原因是国内缺乏睡眠成分自动分析系统(auto-analysis sleeping stages system ,ASS)。要想实现“构想”,当务之急是建立此类系统。
3.1.1家兔睡眠成分自动分析系统家兔为昼行性动物,夜间睡眠为连续性,头大易于进行实验,通过分析脑电图(electroencephalogram, EEG)、肌电图(electromyogram, EMG)和眼电图(electro-oculogram, EOG)在清醒和睡眠中的变化特点和规律,结合特定药物(中枢兴奋药,有代表性的催眠药等)引起的变化,与航空航天大学计算机专家合作建立起家兔睡眠成分自动分析系统,并对此系统进行了稳定性、可信性和准确性试验(原理见大鼠ASS),作为方法学已发表在1996年的中国药理学通报[9]。利用家兔ASS,将一昼夜分成4段,每段6h进行记录和分析,发现以16:00~22:00睡眠
