Ion channel mechanism and ingredient bases of Shenfu Decoction's cardiac electrophysiological effects

Aim of the studyIon channel mechanism of cardiac electrophysiological effects of Shenfu Decoction (SFD, Ginseng and Aconiti Praeparatae Decoction), a traditional Chinese medicine (TCM) prescription, and its ingredient bases were investigated in guinea pigs.Materials and methodsAfter administration of an injection made from SFD (Shenfu Injection, SFI), the indexes of transmembrane action potential (TAP) in vivo and sodium channels in isolated ventricular myocyte were assayed by suspended microelectrodes and patch clamp techniques respectively, and ingredients of SFD were compared with.ResultsAfter administration of SFI, the action potential amplitude (APA) and maximum velocity (Vmax) of TAP decreased. In the presence of either SFI or Fuzi active ingredient (FZAI)(5, 10, and 15%), not any other ingredient, the density of voltage-dependent sodium current (INa) decreased significantly, while the inhibition ratio of SFI was larger. EC50 of SFI was less than the one of FZAI, and SFI displayed effects on INa in wider voltage scope than FZAI in current-voltage curve. Both SFI and FZAI shifted the steady-state inactivation curve of sodium channels to the left, and the recovery curve to the right.ConclusionsThe results indicated that the cardiac electrophysiological effects of SFI were exerted by blocking sodium channels, and FZAI contributed to such effects most but inferior to SFI, which justified its use in anti-arrhythmia, myocardial protection, etc.