Department of Biomedical Sciences, Marshall University, Joan C Edwards School of Medicine, Huntington, WV 25703.
Department of Biomedical Sciences, Marshall University, Joan C Edwards School of Medicine, Huntington, WV 25703
eNeuro. 2020 Oct 15;7(5). doi: 10.1523/ENEURO.0189-20.2020. Print 2020 Sep/Oct.
Previous reports indicate that nicotine reward is mediated through α4β2*, α6β2*, and α4α6β2* nicotinic acetylcholine receptors (nAChRs; * indicates that additional nAChR subunits may be present). Little is known about α4α6β2* nAChR involvement in reward and reinforcement because of a lack of methods that allow the direct investigation of this particular nAChR subtype. Here, we use male and female mice that contain α4-mCherry and α6-GFP nAChR subunits to show that concentrations of nicotine sufficient to evoke reward-related behavior robustly upregulate α4* and α4α6* nAChRs on midbrain dopamine (DA) and GABA neurons. Furthermore, the extent of α4α6* nAChR upregulation on ventral tegmental area (VTA) DA neurons aligns with the magnitude of nicotine reward-related behavior. We also show that the upregulation of nAChRs is accompanied by a functional change in firing frequency of both DA and GABA neurons in the VTA that is directly linked to nicotine reward-related behavior.
先前的报告表明,尼古丁奖赏是通过α4β2*、α6β2和α4α6β2烟碱型乙酰胆碱受体(nAChR;表示可能存在其他 nAChR 亚基)介导的。由于缺乏允许直接研究这种特定 nAChR 亚型的方法,因此对α4α6β2 nAChR 在奖赏和强化中的作用知之甚少。在这里,我们使用含有α4-mCherry 和 α6-GFP nAChR 亚基的雄性和雌性小鼠,表明足以引起奖赏相关行为的尼古丁浓度会强烈地上调中脑多巴胺(DA)和 GABA 神经元上的α4和α4α6 nAChR。此外,腹侧被盖区(VTA)DA 神经元上α4α6* nAChR 的上调程度与尼古丁奖赏相关行为的幅度一致。我们还表明,nAChR 的上调伴随着 VTA 中 DA 和 GABA 神经元放电频率的功能变化,这与尼古丁奖赏相关行为直接相关。