Gill Margaret J, Weiss Mark L, Cain Mary E
Kansas State University, Manhattan, KS 66506, United States; North Central College, Department of Psychology, 30 North Brainard St, Naperville, IL 60540, United States.
Kansas State University, Manhattan, KS 66506, United States.
Drug Alcohol Depend. 2014 Dec 1;145:231-4. doi: 10.1016/j.drugalcdep.2014.09.779. Epub 2014 Oct 13.
Rearing rats in environmental enrichment alters psychostimulant-induced locomotor activity as well as neurotransmitter expression. Exposure to novelty and psychostimulants induces c-fos expression in neurons in the mesolimbic dopamine (DA) pathway. Here we investigated changes in the expression of the immediate early gene c-fos in the mesolimbic DA pathway of enriched, isolated, or socially reared rats due to the neurobiological changes that result from rearing conditions and influence drug taking behavior.
Rats were reared in either enriched (EC), isolated (IC), or social (SC) conditions for 30 days, after which they received an acute amphetamine or saline injection (1.0 mg/kg) and locomotor activity was measured. Following immunohistochemical staining c-fos positive neurons were quantified in the NAcc, mPFC, and amygdala.
Greater locomotor activity was observed in differentially reared rats treated with amphetamine compared to saline, as well as in SC compared to EC and IC rats. Rats reared in an IC context demonstrated greater c-fos expression than EC rats in the NAcc when treated with amphetamine, and EC saline rats demonstrated greater c-fos expression in the cingulate and prelimbic cortices compared to SC saline rats. Additionally, IC amphetamine rats displayed greater c-fos expression in the NAcc compared to IC saline rats, while EC saline rats displayed greater c-fos expression in the prelimbic cortex compared to EC amphetamine rats.
These results suggest regional specificity of psychostimulant-induced c-fos expression in the prelimbic/NAcc pathway that is altered in differential rearing, and influences initial c-fos activation following psychostimulant exposure.
在丰富环境中饲养大鼠会改变精神兴奋剂诱导的运动活动以及神经递质表达。接触新事物和精神兴奋剂会诱导中脑边缘多巴胺（DA）通路神经元中的c-fos表达。在此，我们研究了由于饲养条件导致的神经生物学变化并影响药物摄取行为，在丰富环境、隔离环境或群居环境中饲养的大鼠中脑边缘DA通路中即时早期基因c-fos表达的变化。
将大鼠分别饲养在丰富环境（EC）、隔离环境（IC）或群居环境（SC）中30天，之后对它们进行急性苯丙胺或生理盐水注射（1.0mg/kg）并测量运动活动。免疫组织化学染色后，对伏隔核（NAcc）、内侧前额叶皮质（mPFC）和杏仁核中的c-fos阳性神经元进行定量。
与生理盐水处理组相比，用苯丙胺处理的不同饲养方式的大鼠表现出更大的运动活动，并且与EC和IC大鼠相比，SC大鼠也是如此。在IC环境中饲养的大鼠在接受苯丙胺处理时，伏隔核中的c-fos表达高于EC大鼠，并且与SC生理盐水处理组大鼠相比，EC生理盐水处理组大鼠在扣带回和前额叶皮质中表现出更高的c-fos表达。此外，与IC生理盐水处理组大鼠相比，IC苯丙胺处理组大鼠在伏隔核中表现出更高的c-fos表达，而与EC苯丙胺处理组大鼠相比，EC生理盐水处理组大鼠在前额叶皮质中表现出更高的c-fos表达。
这些结果表明，精神兴奋剂诱导的c-fos表达在前额叶/伏隔核通路中具有区域特异性，这种特异性在不同饲养方式中会发生改变，并影响精神兴奋剂暴露后的初始c-fos激活。
