IONIC BASIS OF EXCITABILITY IN INTRINSIC CARDIAC NEURONS

副交感神经元兴奋性的离子机制 心脏神经节及其神经递质对其功能的作用 将会被研究。神经递质影响多种细胞的功能。 可兴奋细胞中改变静息状态的离子通道和细胞内蛋白 和有源电特性，因此，生理响应 牢房。将在原位研究这两个神经元的离子电流。 豚鼠心脏神经节和分离的心房神经节细胞 单通道全细胞组织培养法生长的豚鼠 膜片钳记录技术。其主要目标是描述 钾选择离子的生物物理和药理性质 心肌神经元上的通道与钾的可能调制 通过各种神经递质进行调节。实验将集中在特定的 慢(钾选择)的离子电导机制 M受体(m-AChR)介导的突触反应 M-乙酰胆碱受体钾通道药理敏感性的测定 针对特定的毒鼠强激动剂和拮抗剂。的影响 神经递质(和特定的拮抗剂)对运动和 将确定已识别的钾通道的通透性 通过测量通过单个钾通道的离子电流。 膜片钳技术为膜的研究提供了独特的优势 涉及细胞内介质的反应(生化第二 信使)在受体和离子通道之间，因为有能力 控制离子成分和施药部位 细胞膜的胞内和胞外表面。这部小说 这项研究将有助于理解离子的神经递质调节 在心脏神经节细胞中的通道，并阐明其机制 化学信号的多样性可以影响神经调节 心脏。

The ionic mechanisms underlying excitability in neurons of parasympathetic ganglia of the heart and the actions of neurotransmitters on their function will be studied. Neurotransmitters influence the function of a variety of ion channels and intracellular proteins in excitable cells to alter resting and active electrical properties and, hence, the physiological responses of the cell. Ionic currents will be studied in neurons of both in situ guinea-pig cardiac ganglia and dissociated ganglion cells from the atria of guinea-pigs grown in tissue culture using single channel and whole cell patch clamp recording techniques. The primary objective is to characterize the biophysical and pharmacological properties of potassium-selective ion channels in cardiac neurons and the possible modulation of potassium channels by various neurotransmitters. Experiments will focus on specific ion conductance mechanisms underlying the slow (potassium-selective) synaptic response mediated by muscarinic receptors (m-AChR) and to determine the pharmacological sensitivity of the m-AChR potassium channels to specific muscarinic agonists and antagonists. The effect of neurotransmitters (and specific antagonists) on the kinetic and permeability properties of identified potassium channels will be determined from measurements of ionic currents through individual potassium channels. The patch clamp method offers unique advantages for the study of membrane responses that involve intracellular mediators (biochemical second messengers) between receptor and ion channel, because of the ability to control the ion composition and locus of drug application on both intracellular and extracellular surfaces of the cell membrane. This novel study will contribute to understanding neurotransmitter modulation of ion channels in cardiac ganglion cells and elucidate mechanisms by which a diversity of chemical signalling can act to influence neural regulation of the heart.