Maldonado R, Robledo P, Chover A J, Caine S B, Koob G F
Département de Chimie Organique, INSERM U. 266 Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France.
Pharmacol Biochem Behav. 1993 May;45(1):239-42. doi: 10.1016/0091-3057(93)90112-7.
Previous work using systemic injections of dopamine receptor antagonists has established that dopamine D1 receptors may have a role in cocaine self-administration. The purpose of the present study was to test the hypothesis that these effects were mediated by dopamine D1 receptors in the region of the nucleus accumbens. Animals were trained to perform operant responses to self-administer cocaine via an IV catheter on a fixed-ratio 5 (FR 5) schedule of reinforcement. SCH23390, a selective D1 dopamine antagonist, significantly increased the self-administration of cocaine when injected into the nucleus accumbens. This increase in self-administration is thought to reflect decreases in the magnitude of the reinforcer, similar to the increase observed when the dose of cocaine is reduced. Similar doses of SCH23390 injected into the posterior caudate nucleus failed to alter cocaine self-administration. These data suggest that D1 receptors in the nucleus accumbens are important for the reinforcing properties of cocaine.
以往使用多巴胺受体拮抗剂进行全身注射的研究已经证实，多巴胺D1受体可能在可卡因自我给药中发挥作用。本研究的目的是检验这样一种假说，即这些作用是由伏隔核区域的多巴胺D1受体介导的。动物通过静脉导管按照固定比例5（FR 5）强化程序接受训练，以进行操作性反应来自我给药可卡因。选择性D1多巴胺拮抗剂SCH23390注入伏隔核时，可显著增加可卡因的自我给药量。这种自我给药量的增加被认为反映了强化物强度的降低，类似于降低可卡因剂量时观察到的增加情况。注入尾状核后部的相似剂量的SCH23390未能改变可卡因的自我给药。这些数据表明，伏隔核中的D1受体对可卡因的强化特性很重要。
