心肌细胞自发性搏动节律的分岔和混沌现象

BIFURCATION AND CHAOS IN THE SPONTANEOUSLY BEATING RHYTHM OF CULTURED CARDIAC MYOCYTES

心脏的节律是复杂的、非线性的;其节律复杂性的起源是多层次的。实验观察了心肌细胞自发性搏动节律的模式,以及改变细胞间耦合强度时节律的转化规律。表明在以正常灌流液灌流状态下,心肌细胞表现为多种不同的节律模式,可以是周期的,也可以是非周期的。当细胞间耦合强度下降时,心肌细胞节律发生转化,并经倍周期分岔进入混沌节律。实验结果有助于更好地理解心脏节律复杂性的起源。

Heart has the properties of a nonlinear oscillator network consisting of different oscillators and can generate complex beating rhythms. There are many causes responsible for the complexity of rhythm. In order to investigate the spontaneously beating rhythms of cultured cardiac myocytes without external stimulation, different patterns of endogenous rhythms in cardiac myocytes were displayed and a novel phenomena was found that the structure of period doubling bifurcation, as well as chaos series occurred in synchronous transition of rhythm while conductance of myocytes was decreased by heptanol. It was suggested that complex patterns of endogenous rhythm can been generated in synchronously beating cardiac myocytes directly and coupling strengths is one of the important cardiac controlling parameters.