Catlow Briony J, Kirstein Cheryl L
Department of Psychology - PCD 4118G, Cognitive and Neural Sciences, University of South Florida, 4202 East Fowler Avenue, Tampa, Fl 33620, USA.
Neurotoxicol Teratol. 2007 Jan-Feb;29(1):57-65. doi: 10.1016/j.ntt.2006.11.007. Epub 2006 Nov 24.
The use of cocaine during adolescent development could alter the normal growth of brain regions affected by cocaine, specifically the reward system, and impact the adult mesolimbic system. However, there is scant literature aimed at determining whether animals are more vulnerable to the adverse effects of drugs during adolescence. The present study investigated whether cocaine pretreatment in either adolescence or adulthood altered the dopaminergic response to a naturally reinforcing substance in adulthood. To evaluate the responsivity of the mesolimbic system after repeated cocaine, sucrose was offered during the dialysis procedure and dialysates were collected. Regardless of age all saline pretreated rats had significant increases in sucrose-induced extracellular dopamine (DA) levels in the nucleus accumbens septi (NAcc) as compared to baseline levels. Rats pretreated with cocaine as adults also had significant increases in DA levels after sucrose. Interestingly, sucrose intake significantly enhanced DA levels in cocaine pretreated adolescent rats as compared to all other conditions. The results from the present study show that in rats pretreated with cocaine during adolescence there is an enhanced response of the dopaminergic system in animals exposed to a naturally reinforcing substance. Therefore, cocaine exposure during adolescence results in long-term functional changes in the mesolimbic pathway. Future studies need to ascertain the underlying mechanisms and their potential role in cocaine addiction.
在青少年发育期间使用可卡因可能会改变受可卡因影响的脑区（特别是奖赏系统）的正常生长，并影响成年期的中脑边缘系统。然而，旨在确定动物在青少年期是否更容易受到药物不良反应影响的文献很少。本研究调查了在青少年期或成年期进行可卡因预处理是否会改变成年期对天然强化物质的多巴胺能反应。为了评估重复使用可卡因后中脑边缘系统的反应性，在透析过程中提供蔗糖并收集透析液。与基线水平相比，无论年龄大小，所有用生理盐水预处理的大鼠伏隔核（NAcc）中蔗糖诱导的细胞外多巴胺（DA）水平均显著升高。成年期用可卡因预处理的大鼠在摄入蔗糖后DA水平也显著升高。有趣的是，与所有其他情况相比，蔗糖摄入显著提高了可卡因预处理的青少年大鼠的DA水平。本研究结果表明，在青少年期用可卡因预处理的大鼠中，暴露于天然强化物质的动物的多巴胺能系统反应增强。因此，青少年期接触可卡因会导致中脑边缘通路的长期功能变化。未来的研究需要确定其潜在机制及其在可卡因成瘾中的潜在作用。
