Heterogeneity of sinoatrial node pacemaker cells

1.起搏器细胞的区域差异和形态学和功能性异质性在兔肺结核（SA）节点中被调查，以及数学模型正在开发中。行动潜力是在SA节点中心最大的，并被减少到基督终结者。对特定通道块的膜当前和影响的分析揭示了这可能是中心快速延迟反应器K+当前和4-氨基吡啶酮-可持续电流的较小密度的结果。在Crista terminalis和connexin 45/connexin 40中存在一个共享的边界，在连接43-表达的动脉myocytes之间，但在endocardial方面，在连接43和连接45-表达合并的地方有一个过渡区。Block of CaイイD12+イエD1 release from sarcoplasmic reticlum by ryanodine shifted the leading pacemaker site from the SA node center toward the septum。在周边地区，瑞安丁抑制的糖尿病 ... More c在不正常的兴奋中经常产生结果，在中心的地方，瑞安丁导致在行动潜力中没有实质性变化。These results suggest that CaイイD12+イエD1 release from sarcoplasmic reticlum may play more important roles in the periphery than in the center. 5。对恒河后血管神经的电刺激导致了一个瞬态起搏器的转变，靠近周边地区的高级或低级Vena Cava。这可能会反映SA节点细胞对乙酰胆碱的响应的区域差异。在外围和SA中心的操作潜力的数学模型是基于膜当前数据开发的。模拟的行动潜力与那些记录的实验和模型行为是一致的，以响应各种离子通道的块也是同样的质量和那些观察到的实验。在一个维度模型中，将区域异质性、内在兴奋在中心启动并推广到周边地区。这些模型为研究SA节点起搏器细胞的生理学意义和区域差异提供了有用的工具。Less（低）

1. Regional differences and morphological and functional heterogeneity of pacemaker cells were investigated in the rabbit sinoatrial (SA) node, and mathematical models were developed.2. Action potential duration was greatest at the center of the SA node and declined to the crista terminalis. Analysis of membrane current and effects of channel-specific blockers revealed that this may be result of smaller density of the rapid delayed rectifier K+ current and the 4-aminopyridine-sensitive sustained current in the center.3. There was a sharply demarcated boundary between connexin43-expressing atrial myocytes in the crista terminalis and connexin 45/connexin40-expressing SA node cells, but on the endocardial side, a transitional zone was detected where connexin43 and connexin45 expression merged.4. Block of CaィイD12+ィエD1 release from sarcoplasmic reticlum by ryanodine shifted the leading pacemaker site from the SA node center toward the septum. In the periphery, ryanodine suppressed diastoli … More c depolarization often resulting in irregular excitation, whereas in the center, ryanodine caused no substantial changes in action potentials. These results suggest that CaィイD12+ィエD1 release from sarcoplasmic reticlum may play more important roles in the periphery than in the center.5. Electrical stimulation of postganglionic vagal nerves caused a transient pacemaker shift toward the periphery close to the superior or inferior vena cava. This may reflect regional differences in the responsiveness of SA node cells to acetylcholine.6. Mathematical models of action potentials in the periphery and center of the SA node were developed based on membrane current data. Simulated action potentials were consistent with those recorded experimentally and model behaviors in response to block of various ion channels were also qualitatively the same as those observed experimentally. In the one dimensional model, incorporating regional heterogeneity, spontaneous excitation initiated in the center and propagated to the periphery. Those models serve useful tools to study the physiological significance of heterogeneity and regional differences of SA node pacemaker cells. Less