CNS DA NEURONS--CELLULAR BASIS OF PATTERNED ACTIVITY

描述（来自申请人摘要）：这是一份修订后的申请的重新提交，该申请扩展了我们之前资助的FIRST奖的一部分所完成的工作。本提案中概述的研究主要集中在对中脑多巴胺神经元复杂活动模式产生所涉及的离子机制的研究。这些研究的理由源于大量文献表明，多巴胺细胞放电模式的改变代表了这些细胞改变其对前脑目标神经元影响的机制。本应用程序中提出的实验的主要目标分为三个具体目标。首先，细胞内和细胞外记录技术将用于识别和表征负责在多巴胺神经元中产生爆发活动的离子机制。这些实验将使我们在实验室开发的模式活动的体外模型，并将重点描述电压门控ca2，通道和兴奋性氨基酸受体在膜电位中产生平台样振荡的作用，这些振荡似乎驱动这些神经元的破裂活动。在第二个具体目标中，电流和电压箝位技术将用于测试假设，即阿帕胺不敏感的Ca2+依赖电导：(1)有助于超极化，终止爆发振荡的平台阶段；(2)通过促进潜在的尖峰频率适应机制，调节爆发内尖峰的时间组织。在第三个也是最后一个目标中，将采用多学科方法，包括分子和电生理学方法，来检验一种假设，即在体外，阿帕胺敏感的Ca2"激活的K+通道的功能表达的增加是导致正常活动模式丧失的原因。通过更清楚地了解这些基本的生理机制，我们希望对DA相关疾病的病因病理学基础以及用于治疗这些疾病的药物的相关药理作用有更多的了解。

DESCRIPTION (from applicant's abstract): This is a resubmission of a revised application that extends work completed as part of our previously funded FIRST Award. The research outlined in this proposal centers on an investigation of the ionic mechanisms involved in generation of the complex activity patterns exhibited by mesencephalic dopamine neurons. The rational for these studies derives from an extensive literature indicating that alterations in dopamine cell firing pattern represent a mechanism through which these cells alter their influence on target neurons in the forebrain. The principal objectives of the experiments proposed in this application are organized into three specific aims. In the first, intra- and extracellular recording techniques will be used to identify and characterize the ionic mechanisms responsible for generating bursting activity in dopamine neurons. These experiments will make us of an in vitro model of patterned activity developed in our laboratory and will focus on delineating the role of voltage-gated Ca 2, channels and excitatory amino acid receptors in generating the plateaulike oscillations in membrane potential that appear to drive bursting activity in these neurons. In the second specific aim, current and voltage clamp techniques will be used to test the hypothesis that an apamin-insensitive Ca2+-dependent conductance: (1) contributes to the hyperpolarization that terminates the plateau phase of the bursting oscillation and (2) regulates the temporal organization of spikes within bursts by contributing to the mechanism underlying spike frequency adaptation. In the third and final aim, a multidisciplinary approach, involving both molecular and electrophysiological approaches will be used to test the hypothesis that an increase in the functional expression of apamin-sensitive Ca2"-activated K+ channels is responsible for the loss Of normal activity patterns in vitro. By more clearly understanding these basic physiological mechanisms, we hope to gain additional insights regarding the etiopathological basis of DA related disorders and the relevant pharmacological actions of the drugs used to treat them.