CircRNA-32011 regulates apoptosis induced by arsenic trioxide in cardiac myocytes / 中国药理学通报

Aim To investigate the effect of circRNA- 32011 on myocardial apoptosis induced by arsenic triox- ide (ATO).Methods Primary cardioniyocytes of suckling neonate mouse were treated with ATO ( final concentration 10 (xniol • L_1 ) for 24 h.Then cell via¬bility was measured by M IT assay.The mKNA expres¬sion levels of Bel-2/ Bax and circRNA-3201 I were de¬tected by KT-PCK.Bcl-2/Bax protein expression lev¬els were detected by Western blot.Overexpression and knock down circHNA-32011 respectively by plasmid and siHNA were used to verify its function in ATO-in- duced cardiomyocyte apoptosis.Results Myocardial cell viability decreased, Bel-2 expression significantly decreased while Bax expression increased in ATO group compared with the control group.CircKNA- 32011 was down-regulated in ATO ineuhated cardio¬niyocytes.Ovcrex press ion of circRNA-32011 in ATO- incubated cardioniyocytes increased myocardial cell vi¬ability and Bel-2 expression and decreased the expres¬sion of Bax.Knockdown of circRNA-32011 could fur¬ther reduce cardiomyoevte activity and Bel-2 expression and increase the experssion of Bax induced by ATO.Conclusions CircRNA-32011 protects cardiac myo¬cytes from apoptosis induced by arsenic trioxide, which may provide a new potential therapeutic strategy for ATO-induced myocardial injury.

M3-R/IK(M3)--a new target of antiarrhythmic agents / 药学学报

<p><b>AIM</b>To investigate the relationship between M3-R/IK(M3) and arrhythmia in order to find a new target for antiarrhythmic agents.</p><p><b>METHODS</b>Using the acute ischemic model of rats and patch-clamp techniques, the effects of the M3 receptor on the occurrence of arrhythmias and its possible mechanisms were studied.</p><p><b>RESULTS</b>In acute ischemic model of rats, the M3 receptor antagonist 4-diphenylacetoxy-N-methylpiperidine-methiodide (4DAMP) increased the occurrence of arrhythmias, and the M3 receptor agonist choline suppressed the onset and the development of arrhythmias (P < 0. 01). No change was observed after treatment with other receptor antagonists (M1, M2, and M4). With patch-clamp techniques, it was found that choline induced K+ current could be inhibited by 4DAMP. Antagonists toward M1, M2, and M4 receptors all failed to alter the current.</p><p><b>CONCLUSION</b>Choline modulates the cellular electrical properties of the heart, probably by activating a K+ current via stimulation of the M3 receptor. M3-R/IK(M3) may act as a new target for antiarrhythmic agents.</p>

Comparison of the anti-arrhythmic effects of matrine and berbamine with amiodarone and RP58866 / 药学学报

<p><b>AIM</b>To clarify mechanisms that the antiarrhythmic effects of matrine and berbamine are weaker than those of amiodarone and RP58866.</p><p><b>METHODS</b>Experimental arrhythmic models were induced by aconitine, coronary artery ligation and electric stimulation in rats and rabbits. Whole-cell patch-clamp techniques were used to record IK1, IKr, IKs and Ito.</p><p><b>RESULTS</b>Matrine and berbamine significantly increased the dose of aconitine for induction of ventricular premature and ventricular tachycardia in rats, decreased the number of arrhythmias induced by coronary artery ligation in rats and increased ventricular fibrillation threshold (VFT) induced by electric stimulation in rabbits, but the anti-arrhythmic potency of matrine and berbamine was lower than that of amiodarone and RP58866. The inhibitory actions of matrine and berbamine on IK1, IKr, IKs, Ito were lower than those of amiodarone and RP58866. The IC50 of matrine for IK1, IKr, IKs, Ito were (46 +/- 3), (32.9 +/- 1.2), (37 +/- 8) and (7.6 +/- 0.5) mol x L(-1), respectively. The IC50 of amiodarone for IK1, IKr, IKs, Ito were (21 +/- 5) , (3.7 +/- 0.7), (5.9 +/- 0.9) and (5.9 +/- 0.6) mol x L(-1), respectively.</p><p><b>CONCLUSION</b>The inhibitory actions of matrine and berbamine on IK1, IKr, IKs, Ito were lower than those of amiodarone and RP58866, which might be the reason that the antiarrhythmic effects of matrine and berbamine were weaker than those of amiodarone and RP58866.</p>