不同剂量纳洛酮对吗啡致大鼠胃肠功能紊乱的影响

目的 探讨不同剂量纳洛酮对吗啡致大鼠胃肠功能紊乱的影响.方法 雄性SD大鼠84只,体重200～250 g,随机分为7组(n=12),生理盐水对照组(NS组)单次皮下注射生理盐水4ml/kg;吗啡组(M组)单次皮下注射吗啡6 mg/kg(混合于Ns中,容积同NS组);不同剂量纳洛酮(1 μg/kg、100 ng/kg、10 ng/kg、1 ng/kg和0.1 ng,kg)混合吗啡(6 mg/kg)组(MNI组、MN2组、MN3组、MN4组和MN5组):分别单次皮下注射混合药液4 ml/kg(按照设定浓度将吗啡和纳洛酮混合于NS中).各组随机取6只大鼠,于给药前、给药后30 min、2、4、24 h时测定血浆胃动素浓度.各组取6只大鼠,自由饮水、进食(饲料中混有高岭土),于进食后12、24 h时测定高岭土摄入量和粪量.结果 与NS组比较,其余各组血浆胃动素浓度升高,高岭土摄入量增多,粪量减少(P＜0.01);与M组比较,MN1组、MN2组和MN3组血浆胃动素浓度降低,高岭土摄人量减少,粪量增多(P＜0.01);与MN1组和MN2组比较,MN4组和MN5组血浆胃动素浓度升高,高岭土摄入量增多,粪量减少(P＜0.01).结论 单次皮下注射纳洛酮1 μg/kg、100 ng/kg、10 ng/kg可减轻吗啡致大鼠胃肠功能紊乱.

Effects of different doses of naloxone on morphine-induced gastro-intestinal dysfunction in rats

Objective To investigate the effects of different doses of naloxone on morphine-induced gastro-intestinal dysfunction.Methods Eighty-four male SD rats weighing 200-250 g were randomly divided into 7 groups(n=12 each):Ⅰ control group received subcutaneous normal saline(NS)4 ml/kg;Ⅱ morphine group (M)received morphine 6 mg/kg S.C.;group Ⅲ-Ⅳ received a mixture of naloxone(1/ μg/kg,100 ng/kg,10 ng/kg,1 ng/kg,0.1 ng/kg)+ morphine 6 mg/kg(MN1-5).Blood samples were taken from 6 animals in each group before and at 30 min,2,4 and 24 h after drug administration for determination of plasma motilin concentration.Six animals in each group Were housed in a metabolism cage for 1 week with food and water available ad libitum for one week.The food contained kaolin.The kaolin intake and weight of feces were measured at 12 and 24 h after drug administration.Results The plasma motilin concentration was significantly lower in group MN1,MN2 and MN3 than in group M.The kaolin intake was significantly lower and weight of feces significantly greater at 12 h after drug administration in group MN1,MN2 and MN3 than in group M.Conclusion Naloxone 1 μg/kg,100 ng/kg,10 ng/kg can aUenuate the gastro-intestinal dysfunction caused by morphine.