Ion Channel Mechanism Of Shenfu Injection's Electrophysiological Effects On Cardiac Muscle And Its Ingredients Bases

PARTâ… ELECTROPHYSIOLOGICAL EFFECTS OF SHENFUINJECTION ON CARDIAC MUSCLE IN VIVOObjective To investigate the electrophysiological effects of ShenfuInjection (SFI) on ventricular myocardium of guinea pig.Methods Healthy adults guinea pigs were selected at random.Transmembrane action potential (TAP) in vivo were investigated withsuspended microelectrodes. SFI and NS (i.p.15ml.kg^-1) was given to 2groups (n=5) of guinea pigs, respectively. The indexes of TAP includedTAPA (TAP amplitude), V_max (maximum velocity), APD10, APD50 andAPD90 (10ï¼…, 50ï¼…and 90ï¼…of action potential duration), RP (restpotential), OS (over shoot), etc. Datas were analyzed with Student-t testand ANOVA.Results SFI could decrease TAPA from (76.8±5.4)mV to(69.0±5.3)mV (P＜0.05) and V_max from (208±14)V·s^-1 to (189±12)V·s^-1 (P＜0.01). NS could turn TAPA from (77.1±9.2)mV to (78.2±10.5)mV,V_max from (208±49)V·s^-1 to (203±40)V·s^-1 (P＞0.05). The differences ofTAPA and V_max, between the two groups were statistically significant(TAPA, P＜0.01; V_max, P＜0.05), while the other indexes including APD10,APD50, APD90, RP, OS had no significance both inner and betweengroups (P＞0.05).Conclusions SFI can decrease transmembrane action pontentialamplitude and maximum velocity of depolarization of guinea pig'smyocytes in vivo, consequently influence the electrophysiologicalcharacteristics of ventricular myocardium, which may explain SFI's effectsof myocardial protection, anti-arrhythmia, etc. PARTâ…¡EFFECTS OF SFI AND ITS MAIN INGREDIENTS ONFAST SODIUM CHANNEL IN VENTRICULARMYOCYTES OF GUINEA PIGObjective Compared with its main ingredients, SFI's direct effectson fast sodium channel of guinea pig's single ventricular myocytes wereinvestigated so as to study ion channel mechanism of SFI'selectrophysiological effects in molecular level and its pharmacologicalbases excepting for interferences from factors in vivo (e.g. nervous systemor extracellular fluid).Methods Single ventricular myocyte was isolated usingacute-collagenase-isolating methods, and I_Na on membrane was recordedusing whole-cell patch clamp technique. Myocytes were divided into 5groups (n=6): S, F, H, D, and A, with 10ï¼…SFI, 10ï¼…fuzi active ingredient(FZAI), 10ï¼…hongshen active ingredient (HSAI), 10mmol·L^-1 demethyl-coclaurine (DMC), and 10ï¼…adjuvant were given, respectively. Further,SFI and FZAI were also observed in a concentration accumulating manner(1.25ï¼…, 2.5ï¼…, 5ï¼…, 10ï¼…, 15ï¼…). Besides, 12 other myocytes were dividedinto 2 groups (n=6): S and F, with 10ï¼…SFI or 10ï¼…FZAI was given,respectively. Datas were dealed by fitting curves, etc, and analysised withStudent-t analysis, ANOVA, and q test. Results The comparison inner group of I_Na density under peakpotential in both group S and F were statistically different, respectively(P＜0.01), while the ones of group H, D, A were not (P＞0.05). Thedifferences between the two and each of them compared with group H, D,A were statistically siginificant (P＜0.01), while the ones between everytwo of group H, D, A were not (P＞0.05). SFI and FZAI can both decreaseINa density concentration-dependently. In group S, the differences betweenevery two concentrations of 1.25ï¼…, 2.5ï¼…, 5ï¼…, 10ï¼…and 15ï¼…weresignificant (P＜0.01), expect for the one between 10ï¼…and 15ï¼…(P＞0.05).In group F, the differences between every two concentrations of 1.25ï¼…,2.5ï¼…, 5ï¼…, 10ï¼…and 15ï¼…were significant (1.25ï¼…and 2.5ï¼…P＜0.05, othersP＜0.01), expect for the one between 10ï¼…and 15ï¼…(P＞0.05). Fitted withHill function, E_max was (22.21±1.15)ï¼…and EC₅₀ was (2.98±0.25)ï¼…as forSFI, while E_max was (19.62±2.81)ï¼…, EC₅₀ was (4.04±0.35)ï¼…for FZAI,respectively. The differences of E_max between the two groups were notsignificant (P＞0.05), but the one of EC₅₀ were significant (P＜0.01). Thecurrent-voltage curve were shifted upwards after treated in both group Sand F, respectively, but activation potential, peak potential and reversalpotential were not changed (P＞0.05): the differences of current densitiesunder every voltage before being treated in both group were not statisticallysignificant (P＞0.05); the differences of current densities under voltages of-40 mV, -30 mV, -20 mV, -10 mV, 0 mV, 15 mV, 30 mV inner group of group S were statistically significant (the last two, P＜0.05, others, P＜0.01),while those under voltages of-50 mV or -45 mV were not statisticallysignificant (P＞0.05); the differences of current densities under voltages of-45 mV, -40 mV, -30 mV, -20 mV inner group of group F were statisticallysignificant (-20 mV, P＜0.05, others, P＜0.01), while those under voltages of-50 mV or -45 mV were not statistically significant (P＞0.05). 10%SFI andFZAI could both shift the inactive-curve of sodium channel to the left, andrecovery curve to the right.The differences of V_1/2,Ï„inner either groupwere significant (P＜0.05), while the ones of K inner either group and all theindexs between the two groups were not (P＞0.05).Conclusions SFI can block I_Na of the ventricular myocyte, enhancefast sodium channels' inactivation and delay its recovery, consequentlyinfluence electrophysiological characteristics of ventricular myocardium,which may explain SFI's effects of anti-arrhythmia, etc. FZAI contributedto such effects most but inprior to SFI, while DMC had no use.