Klebaur J E, Bevins R A, Segar T M, Bardo M T
Department of Psychology, University of Michigan, Ann Arbor, USA.
Behav Pharmacol. 2001 Jul;12(4):267-75. doi: 10.1097/00008877-200107000-00005.
Previous work has shown that individual differences in locomotor activity in an inescapable novel environment can predict acquisition of amphetamine self-administration. The current study examined whether individual differences in approach to novelty in a free choice test could also predict amphetamine self-administration. Further, the current study examined whether individual differences in either free choice or inescapable novelty tests could predict responding for a nondrug reinforcer (sucrose) in the presence and absence of amphetamine. Male and female rats were first tested for their response to free choice novelty (playground maze and novelty-induced place preference tests) and inescapable novelty. They were then tested for acquisition of sucrose-reinforced responding, amphetamine-induced changes in maintenance of sucrose-reinforced responding, and amphetamine self-administration. Based on the inescapable novelty test, acquisition of sucrose-reinforced responding was more rapid in male high responders (HR) compared to low responders (LR). This effect in males did not generalize to females. None of the novelty tests predicted the ability of amphetamine to decrease sucrose-maintained responding. However, using the inescapable novelty test, both male and female HRs self-administered more amphetamine than LRs within the dose range tested (0.03-0.16 mg/kg/infusion). Neither the playground maze nor the novelty-induced place preference test predicted amphetamine self-administration. These results indicate that responses to free choice novelty and inescapable novelty predict different components of amphetamine-induced behavior.
先前的研究表明，在无法逃避的新环境中运动活动的个体差异能够预测苯丙胺自我给药的习得情况。当前的研究考察了在自由选择测试中对新奇事物的接近程度的个体差异是否也能预测苯丙胺自我给药。此外，当前的研究还考察了自由选择或无法逃避的新奇测试中的个体差异是否能预测在有和没有苯丙胺的情况下对非药物强化物（蔗糖）的反应。首先对雄性和雌性大鼠进行自由选择新奇反应测试（游乐场迷宫和新奇诱导的位置偏好测试）以及无法逃避的新奇测试。然后对它们进行蔗糖强化反应的习得、苯丙胺对蔗糖强化反应维持的诱导变化以及苯丙胺自我给药的测试。基于无法逃避的新奇测试，与低反应者（LR）相比，雄性高反应者（HR）中蔗糖强化反应的习得更快。雄性中的这种效应并未推广到雌性。没有一项新奇测试能预测苯丙胺降低蔗糖维持反应的能力。然而，使用无法逃避的新奇测试，在测试剂量范围内（0.03 - 0.16毫克/千克/注射），雄性和雌性HR自我给药的苯丙胺都比LR多。游乐场迷宫和新奇诱导的位置偏好测试都不能预测苯丙胺自我给药情况。这些结果表明，对自由选择新奇和无法逃避新奇的反应能预测苯丙胺诱导行为的不同组成部分。
