Leri Francesco, Rizos Zoe
Department of Psychology, University of Guelph, Guelph (Ontario), N1G 2W1, Canada.
Pharmacol Biochem Behav. 2005 Apr;80(4):621-30. doi: 10.1016/j.pbb.2005.01.013.
To investigate the process of relapse to drug seeking caused by reexposure to drugs, we studied the consequences of recurring instances of stimuli-drug associations using heroin conditioned place preference (CPP) in rats. After original conditioning and extinction, rats received either a single compartment-heroin pairing (reconditioning) or were primed with heroin and tested for reinstatement of CPP. It was found that the session of reconditioning, but not the session of reinstatement, caused the reappearance of a preference for the heroin-paired compartment on a test given 24 h later, in drug-free conditions. The effect of reconditioning was found to be dependent on heroin doses, and was not seen when heroin injections were given outside the conditioning environment. Furthermore, a single session of reconditioning elevated heroin seeking even on a test given 96 h later. Finally, heroin seeking was found to be significantly elevated on a test given 28 days after the last extinction session whether animals received 1 or 3 reconditioning sessions. These results suggest that the motivational value of cues associated with heroin is not eliminated by extinction and, importantly, that these cues can rapidly regain their ability to promote drug seeking behavior if they are re-associated with the effect of heroin.
为了研究再次接触毒品导致复吸寻求毒品的过程，我们利用大鼠海洛因条件性位置偏爱（CPP）实验，研究了刺激-毒品关联反复出现的后果。在最初的条件化和消退后，大鼠接受单次隔室-海洛因配对（重新条件化），或用海洛因进行激发，并测试CPP的恢复情况。结果发现，重新条件化阶段而非恢复阶段，会导致在24小时后无毒品条件下的测试中，对与海洛因配对隔室的偏爱再次出现。重新条件化的效果取决于海洛因剂量，且在条件化环境之外注射海洛因时未观察到该效果。此外，单次重新条件化阶段即使在96小时后的测试中也会提高海洛因寻求行为。最后，无论动物接受1次还是3次重新条件化阶段，在最后一次消退阶段28天后的测试中，海洛因寻求行为均显著增加。这些结果表明，与海洛因相关线索的动机价值不会因消退而消除，重要的是，如果这些线索再次与海洛因的效果相关联，它们能够迅速恢复促进毒品寻求行为的能力。
