Résumé
Abstract only The Zebrafish (ZF) is a tropical fish that has been the focus of an increasing number of developmental studies. However, our understanding of the basic physiology of ZF, in particular cardiac excitation‐contraction coupling is limited. Indeed, there is currently no information about the electrical activity of single myocytes freshly isolated from ZF ventricle; this study addressed this point. Ventricular myocytes were obtained by enzymatic digestion. The patch clamp technique was used to record Na currents (INa), Ca currents (ICa) and action potentials (AP). Results are presented as mean±SE and assessed with paired t‐test. Single ventricular myocytes from ZF are long and thin, as described for other fish species. Cell capacitance was 25.5±0.9 pF (n=81). ICa density (at 0 mV) was −8.4±3.4 pA/pF and INa density (at −40 mV) was −106±18 pA/pF (n=6). Resting membrane potential was −66±2 mV (n=19). At 0.1 Hz stimulation frequency, AP duration at 25, 50, and 90% repolarization was 53±16, 117±26, 155±35 ms, respectively (n=12), indicating the presence of a plateau phase. Increasing stimulation frequency to 2 Hz significantly decreased AP duration (n=12, p<0.05). To conclude, we have developed a method to obtain viable isolated ventricle myocytes from ZF heart. The presence of a plateau during the AP suggests that this species might be appropriate for ion channels related mutation screening of cardiac alteration.