ADULT MAMMALIAN CARDIAC MYOCYTES

我们计划扩展已经开发的分散方法 大鼠、豚鼠和青蛙的单个心肌细胞到更大的物种 像狗、兔子和猫一样。此外，人类心脏的一些特性 将对心肌细胞进行检查。心肌细胞会急剧分散 使用酶解离的方法。严格的评估程序 该方法的成功已经确立，并包括测量 超微结构、生化行为和电生理特性。 广泛的物种表示的有用性源于这样一个事实 每一个物种都有其独特的优势。例如，狗是最受欢迎的 心脏肌膜的准备，兔对起搏器研究有用， 大鼠提供了许多心脏病的遗传模型，青蛙没有T管 此外，还增强了结果的普适性 使用我们的方法。将评估的蜂窝参数包括案例 耐受性、心肌细胞超微结构、电生理特性 包括电缆特性、静息电位、膜电压和 配基门控电流，收缩活性，离子含量，离子通量， 线粒体功能、肌膜结合与环核苷酸 制作。重建实验将在哪一项中进行 膜片钳分离富脂SL囊泡的通道。 我们将特别从以下角度来研究钙通道 二氢吡啶，一类新的重要的钙通道调节剂。这些 药物有激动剂和拮抗剂的作用，是高度有效的，非常 具体的。这些药物与肌膜钙通道的结合将是 与从单通道和整体测量的功能效果进行比较 电池电流。将特别关注依赖国家的 有约束力的。兔心脏起搏电位的电流 起搏器和辅助起搏器组织将被检查并合成 根据这些发现，将对起搏潜力进行评估。 自主神经递质、腺苷和三磷酸腺苷对起搏的影响 还将接受检查。

We plan to extend methods that have been developed for the dispersion of single cardiac myocytes in rat, guinea pig and frog to larger species such as dog, rabbit and cat. In addition some properties of human cardiac myocytes will be examined. Cardiac myocytes will be dispersed acutely using enzymatic methods of dissociation. A rigorous program for evaluting the success of the method has been established and includes measurements of ultrastructure, biochemical behaviour and electrophysiological properties. The usefulness of a wide species representation arises from the fact that each species has special advantages. For example, dog is a favorite preparation for cardiac sarcolemma, rabbit is useful for pacemaker studies, rat provides many genetic models of cardiac disease, frog has no t-tubule system, etc. In addition, the generalizibility of results is enhanced using our approach. Cellular parameters that will be evaluated include Ca tolerance, myocyte ultrastructure, electrophysiological properties including cable properties, resting potential, membrane voltage and ligan-gated current, contractile activity, ion content, ion fluxes, mitochondrial function, sarcolemmal binding and cyclic nucleotide production. Reconstitution experiments will be done in which single channels from lipid-enriched SL vesicles are isolated by patch clamp. Calcium channels will be studied particularly from the point of view of the dihydropyridines, a new important class of Ca channel modulators. These agents have agonist and antagonist effects, are highly potent and very specific. The binding of these agents to sarcolemmal Ca channels will be compared to the functional effects measured from single channel and whole cell currents. Particular attention will be paid to state-dependent binding. The currents underlying the pacemaker potentials in rabbit pacemaker and subsidiary pacemaker tissue will be examined and a synthesis of the pacemaking potential in the light of these findings will be made. The effects of autonomic transmitters, adenosine, and ATP on pacemaking will also be examined.