Cummins Erin, Boughner Emily, Leri Francesco
Department of Psychology, University of Guelph, Guelph, Ontario, Canada.
Neuroreport. 2014 Mar 26;25(5):297-302. doi: 10.1097/WNR.0000000000000084.
It is well established that re-exposure to a context paired with the effects of drugs of abuse can renew extinguished drug seeking behavior. A context, however, typically includes several stimuli, which may differ in their ability to control drug-oriented behaviors. Hence, the primary objective of this study was to assess whether a heroin-induced place preference could be recovered by re-exposure to a contextual stimulus that was part of the conditioning context before extinction. The second objective was to explore the role of the basolateral nucleus of the amygdala (BLA) in this conditioned effect. Male Sprague-Dawley rats were injected with 3 mg/kg heroin and confined in a compartment that was distinguished by a variety of contextual stimuli, including a ceramic floor tile. During extinction, the floor stimulus was removed, and it was reintroduced for a drug-free test of preference. A control experiment evaluated the unconditioned preference for the floor stimulus. It was found that reintroduction of the floor stimulus caused the recovery of heroin place preference. This effect was not observed in rats infused in the BLA with muscimol (0.03 nmol) and baclofen (0.3 nmol) just prior to the test. These data suggest that an extinguished heroin place preference can be renewed by a contextual tactual stimulus that was part of the conditioning context, and that this process requires an intact BLA.
重新接触与滥用药物效应相关联的环境能够使已消退的觅药行为再次出现，这一点已得到充分证实。然而，一个环境通常包含多种刺激，它们对药物导向行为的控制能力可能有所不同。因此，本研究的主要目的是评估重新接触作为消退前条件化环境一部分的情境刺激是否能恢复海洛因诱导的位置偏好。第二个目的是探究杏仁核基底外侧核（BLA）在这种条件化效应中的作用。雄性Sprague-Dawley大鼠注射3mg/kg海洛因，并被限制在一个通过包括陶瓷地砖在内的多种情境刺激来区分的隔室中。在消退过程中，地面刺激被移除，并在无药物的偏好测试中重新引入。一个对照实验评估了对地面刺激的无条件偏好。结果发现，重新引入地面刺激导致海洛因位置偏好的恢复。在测试前向BLA注射蝇蕈醇（0.03nmol）和巴氯芬（0.3nmol）的大鼠中未观察到这种效应。这些数据表明，作为条件化环境一部分的情境触觉刺激可以使已消退的海洛因位置偏好再次出现，并且这个过程需要完整的BLA。
