Pomfrey Rebecca L, Bostwick Tamaara A, Wetzell B Bradley, Riley Anthony L
Psychopharmacology Laboratory, Department of Psychology, American University, Washington, DC 20016, United States.
Psychopharmacology Laboratory, Department of Psychology, American University, Washington, DC 20016, United States.
Pharmacol Biochem Behav. 2015 Oct;137:30-7. doi: 10.1016/j.pbb.2015.08.004. Epub 2015 Aug 6.
The present experiments examined the effects of adolescent nicotine pre-exposure on the rewarding and aversive effects of cocaine and on cocaine self-administration in adult male rats. In Experiment 1, adolescent Sprague-Dawley rats (postnatal days 28-43) were given once daily injections of nicotine (0.6mg/kg) or vehicle and then tested for the aversive and rewarding effects of cocaine in a combined conditioned taste avoidance (CTA)/conditioned place preference (CPP) procedure in adulthood. In Experiment 2, adolescent Sprague-Dawley rats were pre-exposed to nicotine then tested for cocaine self-administration (0.25 or 0.75mg/kg), progressive ratio (PR) responding, extinction and cue-induced reinstatement in adulthood. In Experiment 1, rats showed significant dose-dependent cocaine-induced taste avoidance with cocaine-injected subjects consuming less saccharin over trials, but no effect of nicotine pre-exposure. For place preferences, cocaine induced significant place preferences with cocaine injected subjects spending significantly more time on the cocaine-paired side, but again there was no effect of nicotine history. All rats in Experiment 2 showed clear, dose-dependent responding during cocaine acquisition, PR testing, extinction and reinstatement with no effect of nicotine pre-exposure. These studies demonstrate that adolescent nicotine pre-exposure does not have an impact on cocaine's affective properties or its self-administration at least with the specific parametric conditions under which these effects were tested.
本实验研究了青春期尼古丁预暴露对成年雄性大鼠可卡因奖赏和厌恶效应以及可卡因自我给药的影响。在实验1中，对青春期的斯普拉格-道利大鼠（出生后28 - 43天）每天注射一次尼古丁（0.6mg/kg）或赋形剂，然后在成年期通过联合条件性味觉回避（CTA）/条件性位置偏爱（CPP）程序测试可卡因的厌恶和奖赏效应。在实验2中，青春期的斯普拉格-道利大鼠预先暴露于尼古丁，然后在成年期测试可卡因自我给药（0.25或0.75mg/kg）、渐进比率（PR）反应、消退和线索诱导的复吸。在实验1中，大鼠表现出显著的剂量依赖性可卡因诱导的味觉回避，注射可卡因的受试者在试验中摄入的糖精较少，但尼古丁预暴露没有影响。对于位置偏爱，可卡因诱导了显著的位置偏爱，注射可卡因的受试者在与可卡因配对的一侧花费的时间显著更多，但尼古丁暴露史同样没有影响。实验2中的所有大鼠在可卡因获取、PR测试、消退和复吸过程中均表现出明显的剂量依赖性反应，尼古丁预暴露没有影响。这些研究表明，至少在所测试的特定参数条件下，青春期尼古丁预暴露对可卡因的情感特性或其自我给药没有影响。
