The change of L-type calcium channel current of hypertrophied myocardium and its relation with the left ventricular hypertrophy in spontaneously hypertensive rat

Objective To study the dynamic change of L-type calcium channel current (ICa-L) in hypertrophied myocardium and its relation with the left ventricular hypertrophy in spontaneously hypertensive rat(SHR). Methods ICa-L and membrane capacitance(MC) of the left ventricular myocytes were recorded on 10, 24 and 34-week SHR with the whole-cell patch-clamp technique, at the same time, the systolic blood pressure(SBP) and left ventricular mass index(LVMI) were studied. The 10-week Wistar rat was served as controlled group. Results ①The LVMI and MC of SHR were significantly higher than those of Wistar rat(P0.01). In SHR, the LVMI and MC were significantly different among the three groups(P0.01).②The density of ICa-L in 10-week SHR was significantly higher than that of 10-week Wistar rat (-7.2±0.9 pA/pF vs -5.7±0.6 pA/pF, P0.05), but it of 34-week SHR was significantly lower than that of 10-week Wistar rat (-4.2±0.3 pA/pF vs -5.7±0.6 pA/pF, P0.05).③There was significantly negative relationship between the density of ICa-L and LVMI(r=-0.701, P0.01). The LVMI and the age of rat were dominating risk factors of the density of ICa-L(P0.01). Conclusion The more hypertrophy the left ventricular is, the lower the density of ICa-L is.