COCAINE INHIBITION OF NEURONAL NICOTINIC RECEPTORS

该提案的主要目的是确定可卡因抑制神经元尼古丁受体(NAChRs)的作用机制和结构基础。尽管来自多项研究的证据表明，可卡因抑制多巴胺转运体在介导可卡因的许多成瘾和运动效应中的重要性，但我们的初步数据表明，可卡因可以亚型依赖的方式抑制尼古丁受体，其浓度可能与介导与可卡因使用相关的一些毒性有关。越来越明显的是，大脑尼古丁受体的主要功能是通过突触前效应调节其他神经递质的释放。因此，可卡因的一些作用可能与通过与神经元nAChRs直接相互作用而抑制递质释放有关。该方案利用非洲爪哇卵母细胞表达系统，结合单通道记录、激光脉冲光解和分子生物学来表征可卡因对尼古丁受体的抑制。申请者将接受单通道和宏观受体动力学分析方面的培训，以及在分子生物学方面的额外经验。为了了解可卡因对大脑功能的广泛影响，除了与抑制多巴胺转运体相关的那些部位，包括与神经元尼古丁受体结合的部位外，有必要考虑可卡因对大脑功能的潜在影响。

The main goal of the proposal is to determine the mechanism of action and structural basis for cocaine inhibition of neuronal nicotinic receptors (nAChRs). Although evidence from a number of studies makes clear the importance of cocaine inhibition of the dopamine transporter in mediating many of the addictive and locomotor effects of cocaine, our preliminary data indicate that cocaine can inhibit nicotinic receptors in a subtype-dependent manner at concentrations which are potentially relevant in mediating some of the toxicity associated with cocaine use. It is becoming increasingly apparent that the primary function of brain nicotinic receptors is to modulate the release of other neurotransmitters via presynaptic effects. Thus, it is possible that some of cocaine's effects could be related to inhibition of transmitter release via direct interactions with neuronal nAChRs. The proposal makes use of the Xenopus oocyte expression system in conjunction with single channel recording, laser pulse photolysis and molecular biology to characterize cocaine inhibition of nicotinic receptors. The applicant will gain training in the analysis of single channel and macroscopic receptor kinetics as well as additional experience in molecular biology. In order to understand the wide spectrum of cocaine effects on brain function, it will be necessary to consider the potential for cocaine effects at sites in addition to those associated with inhibition of the dopamine transporter, including binding to neuronal nicotinic receptors.