Aim To explore the reason that the antiarrhythmic effect of the extract oftraditional Chinese medicinal herb, matrine, is weaker than quinidine and verapamil by comparison ofthe effect and efficacy of matrine on vario...Aim To explore the reason that the antiarrhythmic effect of the extract oftraditional Chinese medicinal herb, matrine, is weaker than quinidine and verapamil by comparison ofthe effect and efficacy of matrine on various kinds of transmembrane ionic currents with those ofquinidine and verapamil; and to demonstrate the best targets for antiarrhythmic drugs. MethodsWhole-cell patch-clamp techniques were used to record the action potential and ionic currents insingle cells of rat ventricular myocytes. Aconitine was used to induce the changes of ioniccurrents, then study the effects of matrine and quinidine, verapamil on aconitine-induced unbalancedchannel currents and action potential. Results Aconitine 1 μmol·L^(-1) induced significantchanges in transmembrane currents and action potential in single cells of rat ventricular myocytes.APD was significantly prolonged by aconitine. Simultaneously, aconitine increased sodium, L-typecalcium and inward rectifier potassium currents. Matrine 100 μmol· L^(-1) reversed theaconitine-induced changes of sodium current (I_(Na)) from (-70.2+- 10.5) pA/pF to ( - 39.6+-4.0)pA/pF(n = 5, P < 0.05 vs aconitine); L-type calcium current (I_(Ca-L)) from (20.4+- 3.8) pA/pF to (- 12.9+- 2.9) pA/pF ( n = 6, P < 0.01); the inward rectifier potassium current (I_(k1) ) from (-32.2+- 1.08) pA/pF to ( -24.0+-3.4) pA/pF (n = 6, P < 0.01), and action potential duration. Thereversal effects of quinidine and verapamil on aconitine-induced changes of APD and ionic currentswere more marked than matrine. Conclusion Aco-nitine significantly disturbs the normal equilibriumof ion channels in ventricular myocytes. It induces changes of I_(Na), I_(Ca-L), I_(K1) andprolongation of action potential duration. Matrine at concentration 50 or 100 μmol·L^(-1)statistically significantly suppresses aconitine-induced changes of APD and ionic currents. Thepotency and efficacy of inhibitory effect of matrine are markedly weaker than those of commonly usedverapamil and quinidine.展开更多
Objective To determine whether testosterone modulates markers of cardiomyocytes aging via its classic androgen receptor （AR）-dependent pathway or conversion to estradiol. Methods Male littermates and testicular fem...Objective To determine whether testosterone modulates markers of cardiomyocytes aging via its classic androgen receptor （AR）-dependent pathway or conversion to estradiol. Methods Male littermates and testicular feminized （Tfm） mice were randomly separated into 4 experimental groups： littermate controls （n=8）, Tfm mice （n=7）, testosterone-treated Tfm mice （n=8） and Tfm mice treated with testosterone in combination with the aromatase inhibitor anastrazole （n=7）. Cardiomyocytes were isolated from mouse left ventricles, the activity of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px）, and the amount of malondialdehyde （MDA） were measured us- ing colorimetry method, and expression of p l 6~NKga and retinoblastoma （Rb） proteins were detected by Western blotting. Results The SOD and GSH-Px enzyme activities of cardiomyocytes were decreased, and the MDA levels and the expression of p l 6INK＊a and Rb proteins were increased in Tfm mice compared with control mice. An increase was observed in the activities of SOD and GSH-Px enzyme as well as a decrease in MDA levels and the expression of p 16~NK4a and Rb proteins in the testosterone-treated Tfm mice. After co-treatment with anastrazole in Tfm mice, these improvement were partly inhib- ited. Conclusion Physiological testosterone replacement can delay cardiomyocyte aging in Tfm mice, an effect that is independent of the AR pathway and in part conversion to estradiol.展开更多
文摘Aim To explore the reason that the antiarrhythmic effect of the extract oftraditional Chinese medicinal herb, matrine, is weaker than quinidine and verapamil by comparison ofthe effect and efficacy of matrine on various kinds of transmembrane ionic currents with those ofquinidine and verapamil; and to demonstrate the best targets for antiarrhythmic drugs. MethodsWhole-cell patch-clamp techniques were used to record the action potential and ionic currents insingle cells of rat ventricular myocytes. Aconitine was used to induce the changes of ioniccurrents, then study the effects of matrine and quinidine, verapamil on aconitine-induced unbalancedchannel currents and action potential. Results Aconitine 1 μmol·L^(-1) induced significantchanges in transmembrane currents and action potential in single cells of rat ventricular myocytes.APD was significantly prolonged by aconitine. Simultaneously, aconitine increased sodium, L-typecalcium and inward rectifier potassium currents. Matrine 100 μmol· L^(-1) reversed theaconitine-induced changes of sodium current (I_(Na)) from (-70.2+- 10.5) pA/pF to ( - 39.6+-4.0)pA/pF(n = 5, P < 0.05 vs aconitine); L-type calcium current (I_(Ca-L)) from (20.4+- 3.8) pA/pF to (- 12.9+- 2.9) pA/pF ( n = 6, P < 0.01); the inward rectifier potassium current (I_(k1) ) from (-32.2+- 1.08) pA/pF to ( -24.0+-3.4) pA/pF (n = 6, P < 0.01), and action potential duration. Thereversal effects of quinidine and verapamil on aconitine-induced changes of APD and ionic currentswere more marked than matrine. Conclusion Aco-nitine significantly disturbs the normal equilibriumof ion channels in ventricular myocytes. It induces changes of I_(Na), I_(Ca-L), I_(K1) andprolongation of action potential duration. Matrine at concentration 50 or 100 μmol·L^(-1)statistically significantly suppresses aconitine-induced changes of APD and ionic currents. Thepotency and efficacy of inhibitory effect of matrine are markedly weaker than those of commonly usedverapamil and quinidine.
基金Supported by National Basic Research Program of China(973 Program,2007CB507404)
文摘Objective To determine whether testosterone modulates markers of cardiomyocytes aging via its classic androgen receptor （AR）-dependent pathway or conversion to estradiol. Methods Male littermates and testicular feminized （Tfm） mice were randomly separated into 4 experimental groups： littermate controls （n=8）, Tfm mice （n=7）, testosterone-treated Tfm mice （n=8） and Tfm mice treated with testosterone in combination with the aromatase inhibitor anastrazole （n=7）. Cardiomyocytes were isolated from mouse left ventricles, the activity of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px）, and the amount of malondialdehyde （MDA） were measured us- ing colorimetry method, and expression of p l 6~NKga and retinoblastoma （Rb） proteins were detected by Western blotting. Results The SOD and GSH-Px enzyme activities of cardiomyocytes were decreased, and the MDA levels and the expression of p l 6INK＊a and Rb proteins were increased in Tfm mice compared with control mice. An increase was observed in the activities of SOD and GSH-Px enzyme as well as a decrease in MDA levels and the expression of p 16~NK4a and Rb proteins in the testosterone-treated Tfm mice. After co-treatment with anastrazole in Tfm mice, these improvement were partly inhib- ited. Conclusion Physiological testosterone replacement can delay cardiomyocyte aging in Tfm mice, an effect that is independent of the AR pathway and in part conversion to estradiol.
