Cox B, Ary M, Lomax P
J Pharmacol Exp Ther. 1976 Mar;196(3):637-41.
Stereotyped behavior induced by injection of apomorphine hydrochloride (10 mg/kg i.p) was measured in control rats, rats made dependent on morphine and dependent rats undergoing naloxone-precipitated withdrawal. The dose of apomorphine chosen was approximately the ED50 dose, so that changes in sensitivity to apomorphine in either direction could be determined. Rats which had received a subcutaneous morphine (75 mg) pellet implant 72 hours previously demonstrated an increased sensitivity to apomorphine when compared with placebo-implanted controls. During withdrawal precipitated by injection of naloxone hydrochloride (0.2 mg/kg i.p.) this increased sensitivity disappeared. Naloxone alone, in a dose of 1.0 mg/kg but not 0.2 mg/kg, significantly antagonized apomorphine-induced stereotyped behavior and these effects of apomorphine were also reduced by an acute injection of morphine sulfate (10 mg/kg). The significance of these findings with regard to changes in central dopaminergic systems during dependence and withdrawal is discussed.
在对照大鼠、吗啡依赖大鼠以及经历纳洛酮诱发戒断的依赖大鼠中，测量了注射盐酸阿扑吗啡（10毫克/千克，腹腔注射）所诱发的刻板行为。所选用的阿扑吗啡剂量约为半数有效剂量（ED50），以便能够确定对阿扑吗啡的敏感性在任何一个方向上的变化。与植入安慰剂的对照大鼠相比，72小时前接受皮下植入75毫克吗啡丸的大鼠对阿扑吗啡的敏感性增加。在注射盐酸纳洛酮（0.2毫克/千克，腹腔注射）诱发戒断期间，这种增加的敏感性消失。单独使用剂量为1.0毫克/千克而非0.2毫克/千克的纳洛酮可显著拮抗阿扑吗啡诱发的刻板行为，急性注射硫酸吗啡（10毫克/千克）也可降低阿扑吗啡的这些效应。本文讨论了这些发现对于依赖和戒断期间中枢多巴胺能系统变化的意义。
