Changes in Dopamine Transmission in the Nucleus Accumbens Shell and Core during Ethanol and Sucrose Self-Administration
Changes in Dopamine Transmission in the Nucleus Accumbens Shell and Core during Ethanol and Sucrose Self-Administration
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DOI：
10.3389/fnbeh.2017.00071
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发表时间：
2017-05-01
影响因子：
3
通讯作者：
di Chiara, Gaetano
中科院分区：
文献类型：
--
作者：
Bassareo, Valentina;Cucca, Flavia;di Chiara, Gaetano
乙醇和其他滥用物质一样，在被动给药后优先增加大鼠伏隔核(NAC)中的多巴胺(DA)传递。然而，目前尚不清楚乙醇是否也增加了手术后口服给药(SA)后NAC DA的传递。NAC由腹内侧室、外壳和背外侧室组成，背侧室是核心，在那里DA传递在暴露于滥用药物后做出不同的反应。我们实验室以前的研究调查了对蔗糖颗粒和滥用药物反应的大鼠NAC外壳和核心中透析液DA的变化。作为这些研究的后续，我们最近调查了与口服10%乙醇溶液SA相关的NAC外壳和核心DA传递的变化。为了与使用蔗糖+乙醇溶液的文献进行比较，我们还研究了20%蔗糖和10%乙醇+20%蔗糖溶液中与SA相关的透析液DA的变化。训练大鼠在固定比例1(FR1)戳鼻程序下获得溶液的口服SA。训练结束后，在反应条件(主动)、奖赏遗漏(消退试验)和反应非或有(被动)呈现乙醇、蔗糖或乙醇+蔗糖溶液的情况下，对大鼠进行连续3d的微透析监测。主动和被动乙醇处理使两个NAC亚区的透析液DA的增加相似，而在消退实验中，与核心相比，壳中的DA优先增加。相反，在蔗糖SA和消光条件下，DA仅在壳层中增加。这些观察提供了明确的证据，表明口服10%乙醇SA增加了NAC中的透析液DA，并提示乙醇暴露的条件刺激有助于在乙醇SA后观察到的NAC中透析液DA的增加。比较蔗糖和乙醇SA作用下NAC亚区DA的变化模式，同样表明NAC壳和核心DA在蔗糖和乙醇强化中的作用不同。
Ethanol, like other substances of abuse, preferentially increases dopamine (DA) transmission in the rat nucleus accumbens (NAc) following passive administration. It remains unclear, however, whether ethanol also increases NAc DA transmission following operant oral self-administration (SA). The NAc is made-up of a ventro-medial compartment, the shell and a dorso-lateral one, the core, where DA transmission responds differentially following exposure to drugs of abuse. Previous studies from our laboratory investigated changes in dialysate DA in the NAc shell and core of rats responding for sucrose pellets and for drugs of abuse. As a follow up to these studies, we recently investigated the changes in NAc shell and core DA transmission associated to oral SA of a 10% ethanol solution. For the purpose of comparison with literature studies utilizing sucrose + ethanol solutions, we also investigated the changes in dialysate DA associated to SA of 20% sucrose and 10% ethanol + 20% sucrose solutions. Rats were trained to acquire oral SA of the solutions under a Fixed Ratio 1 (FR1) schedule of nose-poking. After training, rats were monitored by microdialysis on three consecutive days under response contingent (active), reward omission (extinction trial) and response non-contingent (passive) presentation of ethanol, sucrose or ethanol + sucrose solutions. Active and passive ethanol administration produced a similar increase in dialysate DA in the two NAc subdivisions, while under extinction trial DA increased preferentially in the shell compared to the core. Conversely, under sucrose SA and extinction DA increased exclusively in the shell. These observations provide unequivocal evidence that oral SA of 10% ethanol increases dialysate DA in the NAc, and also suggest that stimuli conditioned to ethanol exposure contribute to the increase of dialysate DA observed in the NAc following ethanol SA. Comparison between the pattern of DA changes detected in the NAc subdivisions under sucrose and ethanol SA likewise suggests that the NAc shell and core DA play different roles in sucrose as compared to ethanol reinforcement.