结节乳头体核微量注射GABA_A受体激动剂对大鼠睡眠—觉醒周期的影响

发布时间：2018-05-14 16:04

本文选题：睡眠-觉醒周期 + 能谱　；参考：《兰州大学》2009年硕士论文

【摘要】： 研究背景:脑内GABA能神经元分布于基底前脑(basal forebrain,BF)、视前区(preoptic area,POA)及其邻近区域、结节乳头体核(tubermammillary nucleus,TMN)等区域。已知GABA能神经元在睡眠的启动和维持中起很重要的作用。TMN是组织胺能(histaminergic,HAergic)神经元存在的唯一部位并在觉醒的启动和维持中起重要的作用,该神经元存在GABA_A受体,视前腹外侧区(ventrolateralpreoptic area,VLPO)的80%神经元为GABA并向TMN投射参与觉醒-睡眠周期变化。我们的前期研究表明TMN内GABA在sleep drive过程起一定的作用。但TMN接受GABA_A受体激动剂后睡眠觉醒时相及脑电(electroencephalogram,EEG)变化特征仍不清楚。目的:本研究通过微量注射GABA_A受体的激动剂muscimol于自由活动大鼠TMN,观察睡眠-觉醒周期变化以及对HA引发的觉醒的作用,分析EEG能谱变化,探究TMN的HA能神经元与GABA相互作用对于睡眠-觉醒周期的调节,以及变化过程中EEG变化的特点。方法:雄性SD大鼠,随机分成对照组(n=7),生理盐水组(n=7),muscimol 0.5μg组(n=6)和0.25μg组(n=4),HA组(n=7)、HA+muscimol(n=5)组。水合氯醛(350 mg/kg,ip)麻醉,脑立体定位仪固定,暴露颅骨,在额顶骨的两侧分别植入4个脑电极,在项肌植入3根肌电(electromyogram,EMG),所有的电极连接到一微型插座,以备EEG和EMG记录。两根导管依照Paxinos和Watson的大鼠脑立体定位图谱植入TMN上方2 mm处(以前囟为零点,AP,—4.3 mm;ML,±1.3 mm;DV,—7.4 mm),注射药物针头至TMN(DV,—9.4 mm)。常规消毒,微型插座和导管用牙科水泥固定于颅骨上。大鼠恢复一周后头部微型插座经导线连至脑电仪,EEG信号经Micro 1401MKⅡ(Cambridge Electronic Design Limited(CED),London,UK)转化为数字信号并经spike2(CED)记录到计算机。24 h基础睡眠-觉醒周期记录后药物经导管微量注射入TMN。Muscimol组20:00记录,22:00给药。HA组和HA+muscimol组8:00记录,10:00注射HA,在HA+muscimol组于12:00注射muscimol。各组均记录EEG和EMG 24小时,并以30秒为单位分析睡眠-觉醒周期,并对注药后的bout持续时间及数目改变和转换次数进行分析。用spike2对生理盐水或给药6小时的EEG能谱进行分析,用于分析的能谱位于1-60 Hz。EEG的频率带区分如下:δ:1.2-4 Hz;θ:4.2-8 Hz;α:8.2-12 Hz;β:12.2-30 Hz(包含β_1:12.2-20 Hz;β_2:20.2-30 Hz);γ:30.2-60 Hz。结果:1.各时相的变化:(1)Muscimol 0.25μg组与生理盐水组比较,觉醒(wakefulness,W)在12小时内减少10.98%(P＜0.05),浅慢波睡眠(light slow wavesleep,SWS1)和深慢波睡眠(deep slow wave sleep,SWS2)分别增加22.09%(P＜0.05)和62.08%;muscimol 0.5μg组,W减少19.46%(P＜0.05),SWS1和SWS2分别增加29.34%(P＜0.05)和114.43%(P＜0.05)。各组间异相睡眠(paradoxical,PS)的变化无统计学差异。注射muscimol后经过约42.4分钟潜伏期,药物起效,药效持续三个小时以上。此外,与生理盐水组比较,注射muscimol出现以δ活动增加β活动减少为特征的SWS2的增加,δ活动在各时间点从占总能量的不到25%增加到大于50%,β活动的能量几乎消失。 (2)HA组与生理盐水组比较,12小时内W时间明显增加(P＜0.01),SWS1,SWS2和PS均有不同程度的减少(P＜0.05)。注射HA后经过约37分钟潜伏期,诱发长达三个小时以上的觉醒。Muscimol能逆转HA诱发的以β_2波增多α,θ和δ活动减少为特征的觉醒,并能通过增加δ波来再现SWS2。HA注射后β_2活动在各时间点从占总能量的25%以下增加到大于50%,α,θ,δ活动几乎消失,muscimol能逆转这一作用,使δ活动增加到占总能量的约50%。 2.Bout的变化:Muscimol组与生理盐水组比较,SWS1减少＜120 sec(P＜0.01)而增加120-240 sec(P＜0.05)和＞240 sec(P＜0.05),而且增减与muscimol的剂量呈依赖关系。Muscimol对SWS2的影响与对SWS1的相似。W,120-240 sec(P＜0.05)和＞240 sec(P＜0.05)减少且与剂量有关。PS的改变各组间无差异。另外,给予muscimol后W至SWS,SWS至W,SWS至PS,PS至W的转换次数与生理盐水组比较无变化。结论:1.TMN微量注射muscimol能够通过抑制β波活动,增强δ活动来增加睡眠。Muscimol作为GABA_A受体的激动剂,它的作用提示,TMN的GABA能神经元参与了抑制觉醒,增加慢波睡眠,而对异相睡眠没有影响。 2.Muscimol作为GABA_A受体的激动剂是通过延长睡眠的持续时间,而不是通过增加转换的次数使动物进入睡眠。 3.TMN注射HA可以通过增强β_2波,抑制α,θ和δ活动来促进和维持觉醒,抑制慢波睡眠和异相睡眠。 4.Muscimol可以逆转HA的作用,增强δ活动使觉醒转变为睡眠,提示TMN的GABA能神经元可能通过局部环路抑制HA能神经元的活性。
[Abstract]:GABA - ergic neurons play an important role in the initiation and maintenance of sleep . It is known that GABA - ergic neurons play an important role in the initiation and maintenance of sleep .

AIM : To investigate the changes of sleep - wake cycle and the effects of GABA interaction on the sleep - wake cycle and the characteristics of EEG changes during the course of changes of sleep - wake cycle by means of microinjection of the agonist muscimol of GABA _ A receptor in free - active rats .

Methods : Male SD rats were randomly divided into control group ( n = 7 ) , physiological saline group ( n = 7 ) , muscimol 0.5 渭g group ( n = 6 ) and 0.25 渭g group ( n = 4 ) , HA group ( n = 7 ) , HA + muscimol ( n = 5 ) group . Dental cement for routine disinfection , micro - sockets and catheters is fixed to the skull .

EEG and EMG for 24 hours were recorded at 12 : 00 in HA + muscimol group . The frequency bands of EEG were analyzed . The frequency bands of EEG were analyzed . The frequency bands of EEG were as follows : 未 : 1.2 -4 Hz ; 胃 : 4.2 -8 Hz ; 伪 : 8.2 -20 Hz ; 尾 _ 2 : 20.2 -30 Hz ; 纬 : 30 . 2 - 60 Hz .

Results : 1 . The changes of each time phase : ( 1 ) Muscimol 0.25 渭g group decreased 10.98 % ( P & lt ; 0.05 ) and 62.08 % ( P & lt ; 0.05 ) in 12 hours . The changes of SWS1 and SWS2 increased by 29.34 % ( P & lt ; 0.05 ) and 62.08 % ( P & lt ; 0.05 ) , respectively .

The activity of 尾 _ 2 increased from 25 % of the total energy to more than 50 % , 伪 , 胃 , 未 activities almost disappeared after HA injection , and muscimol could reverse this effect , and the activity of 尾 _ 2 increased to about 50 % of the total energy .

2 . The changes of Bout : Muscimol group compared with physiological saline group , SWS1 decreased < 120 sec ( P < 0.01 ) and increased 120 - 240 sec ( P < 0.05 ) and > 240 sec ( P < 0.05 ) . The effect of Muscimol on SWS2 was similar . W , 120 - 240 sec ( P < 0.05 ) and > 240 sec ( P < 0.05 ) .

Conclusion : 1 . Mcimol can increase sleep by inhibiting 尾 - wave activity . Muscimol is an agonist of GABA _ A receptor .

2 . Muscimol as an agonist of the GABA _ A receptor is by extending the duration of sleep , rather than by increasing the number of conversions .

3 . HA can enhance 尾 _ 2 wave , inhibit 伪 , 胃 and 未 activities to promote and maintain awaking , inhibit slow wave sleep and out - phase sleep .

4 . Muscimol can reverse HA ' s function , enhance the activity of 未 - activity to sleep , and suggest that the GABAergic neurons may inhibit the activity of HA neurons through local loop .

【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R33

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