乳鼠窦房结细胞、心房肌细胞及心室肌细胞动作电位比较

Comparison of the Action Potential in Sino-atrial Node Cells,Atrial Cells and Ventricular Cells of Neonatal Rat

目的研究乳鼠窦房结细胞、心房肌细胞及心室肌细胞的动作电位。方法选12只新生24h内的Wistar大鼠乳鼠,分离培养窦房结细胞、心房肌细胞和心室肌细胞,运用全细胞膜片钳技术记录动作电位。结果窦房结细胞体积小,细而长,呈长梭形,搏动频率为(152.1±10.9)min-1;心房肌细胞体积亦较小,梭形或三角形,搏动频率为(116.3±8.6)min-1;心室肌细胞体积较大,可伸出伪足并交织成网,呈短梭形、多角形或不规则形,搏动频率为(92.4±9.3)min-1,3种细胞的搏动频率差别均有统计学意义(P<0.01)。3种细胞的静息电位分别为(-41.3±4.0),(-50.7±2.9)及(-59.8±2.1)mV,差别无统计学意义(P>0.05)。心室肌细胞的APD20,APD50和APD90均较心房肌细胞延长,差别具有统计学意义(P<0.05)。结论 3种细胞形态各异,窦房结细胞具有自发性搏动,心室肌细胞动作电位时程较心房肌细胞长。

Objective To study the action potential of sinoatrial node cells,atrial cells,and ventricular cells of neonatal rat. Methods Sinoatrial node cells,atrial cells,and ventricular cells were isolated and cultured by“enzymolysis with differential attachment”method from 12 neonatal Wistar rats within 24 hours. Whole-cell patch clamp technique was used to record the action potential of the three kinds of myocytes. Results Sinoatrial node cells were small and slim with a spindle shape and frequencies at(152.1±10.9)beats/min. The atrial cells also had small body with nearly spindle like or triangular shape,and with the beating rate of(116.3±8.6)beats/min. The ventricular cells had large body,multi-stretch pseudopodia,and the shapes of short spindle,polygonal,or irregular shape. The beating rates of which were(92.4±9.3)beats/min.Significant difference in beating rates was observed among three kinds of cells(P<0.01). The resting potential of the three kinds of cells were(-41.3±4.0)mV,(-50.7±2.9)mV,and(-59.8±2.1)mV,respectively,with no significant difference(P>0.05). APD 20,APD 50,and APD 90 in ventricular cells were longer than those in atrial cells and there were statistical differences(P>0.05). Conclusions Three kinds of cells are different in shape. Sinoatrial node cells have spontaneous pulsatility.The action potential duration of ventricular cells is longer than that of atrial cells.