小剂量纳洛酮对吗啡致大鼠自主活动的影响

Effects of low doses of naloxone on morphine-induced autonomic activity reduction in rats

目的观察小剂量纳洛酮对吗啡致大鼠自主活动的影响。方法 36只雄性SD大鼠,根据皮下注射药物的不同将其随机分为6组,吗啡对照组(M组,皮下注射15mg/kg的吗啡),吗啡复合纳洛酮组(MN组),根据纳洛酮的剂量大小(1μg/kg,100ng/kg,10ng/kg,1ng/kg和0.1ng/kg),MN组分为MN1、MN2、MN3、MN4和MN5。测定药物注射前(T1)、注射后10min(T2)、20min(T3)、30min(T4)、45min(T5)、60min(T6)、90min(T7)、120min(T8)对大鼠的自主活动评分(水平运动和垂直运动评分)。结果注射吗啡后,M组大鼠自主活动从T3点显著降低,持续至T5点(P<0.05);其他各时间点相互比较差异没有统计学意义(P>0.05);与M组比较,MN1、MN2、MN3组的自主活动评分在T3、T4、T5三个时间点显著升高(P<0.01)。结论 10ng/kg-1μg/kg的纳洛酮对15mg/kg的吗啡所引起大鼠自主活动减少有拮抗作用。

Objective To observe the effects of low doses of naloxone on morphine-induced rat autonomic activities. Methods Thirty-six adult male Sprague-Dawley rats were randomly divided into six groups（6 rats for each group）.Rats in morphine group received 15 mg/kg of morphine.The different doses of naloxone（1 μg/kg,100 ng/kg,10 ng/kg,1 ng/kg and 0.1 ng/kg）and 15 mg/kg of morphine were given in MN1,MN2,MN3,MN4 and MN5 groups.Autonomic activities（horizontal movements and vertical movements）were measured before injection（T1）and after subcutaneous injection of morphine alone or plus naloxone for 10 min（T2）,20 min（T3）,30 min（T4）,45 min（T5）,60 min（T6）,90 min（T7）,120 min（T8）. Results After injection of morphine,the autonomic activities in morphine group significantly decreased at T3,T4 and T5（P〈0.05）.Compared with morphine group,autonomic activities significantly increased in MN1,MN2,MN3 groups at T3,T4 and T5（P〈0.01）. Conclusion Low doses of naloxone 10 ng/kg^-1 μg/kg has an antagonistic effect on autonomic activity reduction induced by 15 mg/kg morphine in rats.