Cocaine self-administration in rats with histories of cocaine exposure and discrimination
Cocaine self-administration in rats with histories of cocaine exposure and discrimination
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DOI：
10.1007/s00213-006-0364-9
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发表时间：
2006-06-01
影响因子：
3.4
通讯作者：
Stolerman, I. P.
中科院分区：
文献类型：
--
作者：
Childs, E.;Shoaib, M.;Stolerman, I. P.
基本原理：精神活性药物的区别性刺激和强化特性之间的相互关系以及它们相互作用以控制药物摄入的方式尚不清楚。研究表明，药物史可以影响药物产生的行为效应的表达。目的：本研究探讨了收购和维持静脉注射可卡因自我管理的历史药物歧视的大鼠。研究方法：两组雄性hooded大鼠（每组n = 12）成功地训练了单杠杆食物强化程序，以区分可卡因（10 mg/kg）和盐水。对照组（每组n = 12）仅接受药物注射和/或生理盐水注射，并接受无辨别训练的食物挤压。随后，所有受试者均植入慢性颈静脉导管，并允许鼻戳以输注可卡因（每次输注0.2 mg/kg）。结果：所有组的初始应答率相似。可卡因暴露组大鼠获得FR-10给药时间表的自我给药明显快于所有其他组（P < 0.02）。有没有组之间的可卡因和生理盐水的临界点上的渐进比例的自我管理的时间表的差异。通过两种方法获得剂量-反应函数，所有组的剂量-反应函数相似。结论：这些结果与早期的研究表明，弱致敏的初级强化性能的可卡因预暴露大鼠是一致的。以前学习辨别可卡因损害了这种敏感性。
Rationale: Interrelationships between the discriminative stimulus and reinforcing properties of psychoactive drugs and the way in which they may interact to control drug intake are unclear. Studies have shown that drug history can influence the expression of drug-produced behavioral effects. Objective: The present study examined the acquisition and maintenance of intravenous cocaine self-administration in rats with a history of drug discrimination. Methods: Two groups of male hooded rats (n = 12 each) were successfully trained in a single-lever food-reinforced procedure to discriminate cocaine (10 mg/kg) from saline. Control groups (n = 12 each) received drug injections and/or saline injections only and lever-pressed for food reinforcers with no discrimination training. Subsequently, all subjects were implanted with chronic jugular catheters and allowed to nose-poke for infusions of cocaine (0.2 mg/kg per infusion). Results: Initial rates of responding were similar for all groups. Acquisition of self-administration on a FR-10 schedule of drug delivery was significantly faster for cocaine-exposed rats in comparison to all other groups (P < 0.02). There were no differences between groups in the breaking points of cocaine and saline on a progressive ratio schedule of self-administration. Dose-response functions were obtained by two methods and were similar for all groups. Conclusion: These results are consistent with earlier studies demonstrating weakly sensitized primary reinforcing properties of cocaine in preexposed rats. Previous learning to discriminate cocaine impaired this sensitization.