中枢内源性大麻素在快动眼睡眠剥夺导致的内脏感觉降低中的作用

Effects of central endocannabinoid system on visceral hyposensitivity induced by rapid eye movement sleep deprivation： experiment with rats

目的研究中枢内源性大麻素系统是否参与快动眼（REM）睡眠剥夺导致的内脏感觉降低。方法采用花瓶技术制作大鼠REM睡眠剥夺模型，24只SD大鼠随机分成实验对照组（YC组），睡眠剥夺组（SD组）和睡眠剥夺加大麻素CB1受体拮抗剂利莫那班组（Rim组）。睡眠剥夺持续48h后对各组大鼠行结直肠扩张（CRD），同时用电生理记录仪记录腹壁肌电活动，以反映内脏感觉的变化。分别采用RT-PCR和蛋白质印迹技术测定YC组和SD组大鼠丘脑、脑干、脊髓（腰髓）中CB1受体、脂肪酸酰水解酶（FAAH）和单酰甘油脂肪水解酶（MGL）mRNA和蛋白表达。结果（1）给予40、60、80mmHg（1mm Hg=0．133kPa）扩张结直肠后，SD组腹外斜肌放电次数（次：220±94、313±162、493±279）均显著低于YC组（次：5064±223、10534±548、16324±249，均P〈0．05）；Rim组（次：668±257、11444±93、16534±153）均显著高于SD组（均P〈0．01），Rim组与YC组差异无统计学意义（均P〉0．05）。（2）丘脑、脑干、脊髓中CB1受体mRNA以及蛋白表达SD组均显著高于YC组（均P〈0．05），而FAAH、MGL表达量则显著低于YC组（均P〈0．05）。结论REM睡眠剥夺导致的内脏感觉降低可能与中枢内源性大麻素受体表达增加、代谢降低有关。

Objective To study the effects and role of central endocannabinoid system in the mechanism of visceral hyposensitivity induced by rapid eye movement （REM） sleep deprivation. Methods Twenty-four SD rat were divided randomly in to 3 groups： cage-yoked group （ YC Group, experimental control group）, REM sleep deprivation group （SD Group） exposed to REM sleep deprivation by means of flower pot technique lasting for 48 hours, and Rim Group, receiving rimonabant, a cannabinoid antagonist, after REM sleep deprivation. 48 hours after the sleep deprivation abdominal electromyogram in response to colorectal distension （CRD） was recorded to asses the visceral sensitivity. Then the rats were killed with their central nervous system taken out. RT-PCR and Western blotting were used to detect the RNA and protein expression of cannabinoid receptor CB1, fatty acid amide hydrolase （FAAH）, and monoacylglycerol lipase （MGL） in the thalamus, brain stem, and spinal cord. Results （1） Under the pressures of 40, 60, and 80 mm Hg, the abdominal electrical activity frequencies of external oblique muscle responding to CRD in SD Group were （220±94）, （313 ± 162）, and （493 ±279） times respectively, all significantly lower than those in YC Group [ （ 506± 223 ）, （ 1053 ± 548 ）, and （ 1632± 249 ） times respectively, all P 〈 0. 05 ], and those of Rim Group were （ 668 ± 257 ）, （ 1144 ± 93 ）, and （ 1653 ± 153 ） times respectively, all significantly higher than those of SD Group （ all P 〈 0. 05 ）, but not significantly different from those of YC Group. （2）The RNA and protein expression levels of CB1 receptor in the thalamus, brain stem , and spinal cord of SD Group were all significantly higher than those of YC Group（ all P 〈 0. 05 ） , while the RNA and protein expression levels of FAAH and MGL in the thalamus and spinal cord of SD Group were all significantly lower than those of YC Group （ all P 〈 0. 05 ）. Conclusion The visceral hyposensitivity induced by REM sleep deprivation may be associated with the increase of expression of CNS endocannabinoid receptor and decrease of its metabolism.