PREEXPOSURE TO AMPHETAMINE AND NICOTINE PREDISPOSES RATS TO SELF-ADMINISTER A LOW-DOSE OF COCAINE
PREEXPOSURE TO AMPHETAMINE AND NICOTINE PREDISPOSES RATS TO SELF-ADMINISTER A LOW-DOSE OF COCAINE
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DOI：
10.1007/bf02245147
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发表时间：
1992-06-01
影响因子：
3.4
通讯作者：
SCHENK, S
中科院分区：
文献类型：
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作者：
HORGER, BA;GILES, MK;SCHENK, S
在接受安非他明（1.0 mg/kg，IP）、尼古丁（0.6 mg/kg基重，SC）或溶剂每日9次注射的大鼠中测量了低剂量（0.25 mg/kg/输注）静脉内可卡因自我给药的获得。对于对照大鼠，自我给药的获得是逐渐的，在第3天和第9天之间，每2小时每日试验期的反应次数增加。相比之下，大鼠预先暴露于安非他明和尼古丁表现出升高的反应手段在早期的测试，这表明更快速的收购。所有组最终都达到了相似的渐近响应水平。在测试的早期，在预先暴露于安非他明和尼古丁的大鼠中观察到的反应增强是由于可靠地自我施用可卡因的受试者数量增加。因此，预先接触安非他明和尼古丁的大鼠似乎更容易受到可卡因的强化作用。在自我管理的数据相反，预先暴露于尼古丁未能敏感的可卡因的运动激活作用的大鼠。事实上，相同的暴露前方案似乎对可卡因的这种作用产生了耐受性。这些数据提供证据表明，不同的机制可能介导的可卡因的增强和自发激活作用的敏化。
The acquisition of low-dose (0.25 mg/kg/infusion) intravenous cocaine self-administration was measured in rats that had received nine daily injections of amphetamine (1.0 mg/kg, IP), nicotine (0.6 mg/kg base weight, SC) or vehicle. For control rats, the acquisition of self-administration was gradual with the number of responses per 2 h daily test session increasing between days 3 and 9. By comparison, rats preexposed with amphetamine and nicotine demonstrated elevated response means during the early days of testing, suggesting more rapid acquisition. All groups eventually reached similar asymptotic levels of responding. The enhanced responding observed during the early days of testing in the rats preexposed with amphetamine and nicotine was due to an increased number of subjects that reliably self-administered cocaine. Thus, the rats preexposed with amphetamine and nicotine seemed predisposed to the reinforcing effects of cocaine. In contrast to the self-administration data, preexposure to nicotine failed to sensitize rats to the locomotor activating effects of cocaine. In fact, the same preexposure regimen appeared to produce tolerance to this effect of cocaine. These data give evidence that different mechanisms may mediate sensitization to the reinforcing and locomotor activating effects of cocaine.