Marchant James L, Smith Frank M, Farrell Anthony P
Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.
Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada.
Curr Res Physiol. 2022 Jan 17;5:48-54. doi: 10.1016/j.crphys.2022.01.002. eCollection 2022.
Blebbistatin potently inhibits actin-myosin interaction, preventing contractile activity of excitable cells including cardiac myocytes, despite electrical excitation of an action potential (AP). We collected intracellular microelectrode recordings of pacemaker cells located in the sinoatrial region (SAR) of the zebrafish heart at room temperature and during acute warming to investigate whether or not blebbistatin inhibition of contraction significantly alters pacemaker cell electrophysiology. Changes were evaluated based on 16 variables that characterized the AP waveform. None of these AP variables nor the spontaneous heart rate were significantly modified with the application of 10 μM blebbistatin when recordings were made at room temperature. Compared with the control group, the blebbistatin-treated group showed minor changes in the rate of spontaneous diastolic depolarization ( = 0.027) and the 50% and 80% repolarization ( = 0.008 and 0.010, respectively) in the 26°C-29°C temperature bin, but not at higher temperatures. These findings suggest that blebbistatin is an effective excitation-contraction uncoupler that does not appreciably affect APs generated in pacemaking cells of the SAR and can, therefore, be used in zebrafish cardiac studies.
blebbistatin能有效抑制肌动蛋白-肌球蛋白相互作用，尽管动作电位（AP）发生电兴奋，但仍可防止包括心肌细胞在内的可兴奋细胞的收缩活动。我们在室温下以及急性升温过程中，收集了位于斑马鱼心脏窦房区域（SAR）的起搏细胞的细胞内微电极记录，以研究blebbistatin对收缩的抑制是否会显著改变起搏细胞的电生理。根据表征AP波形的16个变量评估变化。在室温下进行记录时，施加10μM blebbistatin后，这些AP变量和自发心率均未发生显著改变。与对照组相比，在26°C - 29°C温度区间，blebbistatin处理组的自发舒张期去极化速率（P = 0.027）以及50%和80%复极化（分别为P = 0.008和0.010）有轻微变化，但在更高温度下则没有。这些发现表明，blebbistatin是一种有效的兴奋-收缩解偶联剂，不会明显影响SAR起搏细胞产生的AP，因此可用于斑马鱼心脏研究。
