去甲肾上腺素在快动眼睡眠剥夺降低大鼠内脏感觉功能中的作用

目的 研究去甲肾上腺素(NE)在快动眼(REM)睡眠剥夺降低大鼠内脏感觉功能中的作用.方法 大鼠随机分为实验对照组(YC)、REM睡眠剥夺组(SD)、REM睡眠剥夺后育亨宾干预组(YSD).采用"花瓶技术"对SD组及YSD组进行REM睡眠剥夺48 h,YSD组在48 h时给予腹腔注射育亨宾.造模完成后行结直肠扩张(CRD),观察各组大鼠疼痛感觉阈值,记录大鼠的腹壁肌电图了解腹壁肌的放电次数.采用RT-PCR半定量检测丘脑及肠道组织单胺氧化酶A(MAO-A)和酪氨酸羟化酶(TH)基因表达水平.结果 REM睡眠剥夺48 h时各组大鼠在20、40、60、80 mm Hg(1 mm Hg=0.133 kPa)扩张压力下的腹壁肌放电结果显示:(1)SD组大鼠扩张刺激后的腹壁肌放电次数(178±98、839±323、1331±444、1703±478)显著低于YC组(413±171、1400±245、2070±386、2510±469),且疼痛感觉压力阈值显著增高(P＜0.05);(2)YSD组大鼠扩张刺激后的腹壁肌放电次数(415±212、1490±227、2129±435、2381±399)明显高于SD组,且疼痛感觉压力阈值显著降低(P＜0.05);(3)SD组REM睡眠剥夺48 h后,丘脑及肠道中MAO-A mRNA的水平明显低于YC组(P＜0.05),而TH mRNA的表达显著增高(P＜0.05).结论 REM睡眠剥夺降低大鼠的内脏感觉功能与NE合成增加及代谢减少有关,α2受体拮抗剂可提高大鼠的内脏感觉功能.

The role of norepinephrine in down-regulation of visceral sensitivity in rats deprived of rapid eye movement sleep

OBJECTIVE: To investigate the role of norepinephrine in the down-regulated visceral sensitivity of rats deprived of rapid eye movement (REM) sleep. METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into 3 groups: cage-yoked rats as control (YC), rats with REM sleep deprivation (SD) and rats with yohimbine administered intraperitoneally after REM sleep deprivation (YSD). Flower pot technique was employed to make sleep deprivation model. YSD group was given yohimbine intraperitoneally at the 48th hour after REM sleep deprivation. After both SD and YSD groups had completed these processes, rats of all the three groups were given colorectal distension (CRD) and electromyogram (EMG) was recorded at the same time. The number of discharges of EMG and the threshold of pain perception of the rats were observed to evaluate the visceral sensitivity. The thalamus, rectum and distal colon were taken after CRD; MAO-mRNA and TH-mRNA in three tissues were detected with RT-PCR. RESULTS: On 48th hour, the number of discharges of EMG in 10 seconds responding to CRD in group SD was significantly less than that in group YC and the threshold of pain perception in group SD was higher than that in group YC (P < 0.05). The number of discharge of EMG in group YSD was significantly more than that in group SD (P < 0.05). The expression of MAO-mRNA in group SD was lower than that in group YC (P < 0.05) and the expression of TH-mRNA in group SD was higher than that in group YC (P < 0.05). CONCLUSIONS: The visceral sensitivity in rats is down-regulated by REM sleep deprivation, which can increase synthesis of norepinephrine. Norepinephrine can modulate visceral sensitivity.