Activation of purinergic receptors triggers oscillatory contractions in adult rat ventricular myocytes.
Activation of purinergic receptors triggers oscillatory contractions in adult rat ventricular myocytes.
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嘌呤能受体的激活触发成年大鼠心室肌细胞的振荡收缩。
DOI：
10.1161/01.res.79.1.94
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发表时间：
1996
影响因子：
20.1
通讯作者：
Bond,M
中科院分区：
文献类型：
--
作者：
Zhang,BX;Ma,X;McConnell,BK;Damron,DS;Bond,M
细胞外ATP是一种重要的神经递质，通过激活嘌呤能受体来调节心脏功能。本研究观察了P_2受体激活对成年大鼠心室肌细胞收缩和[Ca~(2+)]i的影响。用Fura-2测定细胞内钙离子浓度，用视频边缘检测法测定细胞收缩。静息心肌细胞灌流2-甲硫基-5‘-三磷酸-S引起收缩和[Ca~(2+)]i振荡，振荡频率随2-M-S-三磷酸腺苷浓度的增加而增加，但收缩幅度因细胞而异，与2-M-S-三磷酸腺苷浓度无关。在电刺激过程中，心肌细胞上的嘌呤能受体的激活增强了收缩的幅度，并引发了心律失常。在静止的心肌细胞群体中，由2-M-S-三磷酸腺苷诱发的[Ca~(2+)]_i信号的平台期可代表单个细胞内[Ca~(2+)]_i的总振荡。用thapsigarin或咖啡因预先处理静止心肌细胞，可减少或取消收缩和2-M-S-三磷酸腺苷激活的[Ca~(2+)]的振荡，表明这种振荡依赖于肌浆网对Ca~(2+)的摄取和释放。这些数据证明了一种新的现象，即激活静止的心肌细胞中的嘌呤能受体刺激[Ca~(2+)]i和收缩的振荡。在电刺激的心肌细胞中，嘌呤能受体的激活触发振荡性收缩，并增强电触发收缩的幅度。
Extracellular ATP is an important neurotransmitter that modulates cardiac function by activation of purinergic receptors. In this study, the effect of P2purinergic receptor activation on contractions and on [Ca2+]iwas investigated in adult rat ventricular myocytes. Fura 2 was used to measure [Ca2+]i, and video edge detection was used to measure contraction. Superfusion of 2-methylthio-adenosine-5′-triphosphate (2-M-S-ATP) over quiescent myocytes induced oscillations in contraction and in [Ca2+]i. The frequency of the oscillatory contractions increased with increasing concentrations of 2-M-S-ATP, but the amplitude of contractions varied from cell to cell and was independent of the concentration of 2-M-S-ATP. During electrical stimulation, activation of purinergic receptors in myocytes potentiated the amplitude of contraction and induced arrhythmias. In populations of quiescent myocytes, the plateau phase of the [Ca2+]isignal evoked by 2-M-S-ATP could be shown to represent summed oscillations in [Ca2+]iin individual cells. Pretreatment of quiescent myocytes with thapsigargin or caffeine reduced or abolished the oscillations in contractions and in [Ca2+]itriggered by 2-M-S-ATP, indicating a dependence of the oscillations on uptake and release of Ca2+by the sarcoplasmic reticulum. These data demonstrate the novel phenomenon that activation of purinergic receptors in quiescent myocytes stimulates oscillations in [Ca2+]iand contraction. In electrically stimulated myocytes, activation of purinergic receptors triggers oscillatory contractions and potentiates the amplitude of electrically triggered contractions.