大麻素受体-1对内毒素诱导的大鼠小肠肌电活动的影响

目的研究不同浓度脂多糖（lipopolysaccharides,LPS）对大鼠小肠肌电活动的影响及大麻素1受体（CB1受体）激动剂HU210和拮抗剂AM251对这些影响的干预作用,以探讨LPS影响肠道运动的可能的机制。方法将48只SD雄性大鼠分为3大组8小组（每小组6只）：LPS处理组（包括LPS低浓度组、LPS高浓度组）,CB1受体激动剂干预组（包括HU210组、LPS低浓度＋HU210组、LPS高浓度＋HU210组）,CB1受体拮抗剂干预组（包括AM251组、LPS低浓度＋AM251组、LPS高浓度＋AM251组）。分别经腹腔注射各种相应药物,用Power Lab八道生理记录仪记录大鼠小肠平滑肌峰电活动的频率及振幅等,观察腹腔注射LPS、大麻素受体激动剂及拮抗剂后这些指标的变化。结果腹腔注射不同浓度LPS后,大鼠小肠平滑肌峰电频率和振幅均有明显降低（P〈0.05）;注射HU210后,大鼠小肠平滑肌峰电频率和幅度也均明显降低（P〈0.05）;而注射AM251后,大鼠小肠平滑肌峰电频率及幅度明显增加（P〈0.05）;腹腔注射不同浓度LPS和HU210,分别与LPS单独注射的比较,小肠平滑肌峰电频率更为降低,注射后30-60 min之间降低最为显著（P〈0.05）;腹腔注射不同浓度LPS和AM251,分别与LPS单独注射比较,肠平滑肌峰电频率升高,AM251逆转LPS的效应主要在注射后的30 min内,尤其对放电频率的逆转作用明显（P〈0.05）。结论腹腔注射LPS有降低大鼠小肠平滑肌电峰电频率和振幅的作用,且有浓度依赖性;CB1受体激动剂和拮抗剂对LPS诱导的大鼠小肠平滑肌峰电活动变化均有不同程度的影响,揭示CB1受体存在于大鼠体内,并参与内毒素血症时肠道运动紊乱的调节。

Effects of Cannabinoid-1 receptor on the intestinal myoelectric disturbance induced by lipopolysaccharide in rat

Objective To study the effect of different concentrations of LPS on rat intestinal myoelectric activity and the possible mechanism related to cannabinoid （CB） receptor. Methods Forty-eight male rats were allocated randomly into three groups and 8 subgroups, with 6 animals in each subgroup：LPS treated groups （incliding LPS low and high concentration groups）, CB1 receptor agonist HU210 treated groups （ including HU210 group, HU210 ＋ LPS low or high concentration groups）, CB1 receptor antagonist AM251 treated groups （ including AM251 group, AM251 ＋ LPS low or high concentration groups）. The frequency and amplitude of the myoelectric spiking activity （SA） in the rat jejunum were recorded by using a Power Lab device after injecting peritoneally （ip） different drugs. Results After injection of different concentration of LPS, the frequency and amplitude of SA decreased obviously （P 〈 0.05）. The frequency and amplitude of SA were reduced by HU210 （P 〈 0.05 ）, but were raised by AM251 （P 〈 0.05 ）. Compared with the LPS injection alone, the frequency of SA decreased obviously in different concentrations of LPS ＋ HU210 groups and the reduction was even more significant between 30 min to 60 min after the injection （ P 〈 0.05 ）. Noticeably, the decreased frequency of SA induced by LPS could be reversed by CB1 receptor antagonist AM251 and the effect was more obvious in 30 min after AM251 injection （ P 〈 0.05 ）. Conclusion LPS causes decrease in the frequency and amplitude of SA in rat jejunum in a concentration-dependent manner. CB1 receptor existing in rat gastrointestinal tract takes part in the regulation of the changed SA induced by LPS.