The effects of H-89 on membrane ion currents in rat ventricular myocytes / 中国药理学通报

ABSTRACT

Aim To assess the effects of N -[2-p-bromo-cinnamylamino-ethyl]-5-isoquinoline-sulfonamide (H-89), a potentially selective inhibitor of Protein Kinase A (PKA), on cardiac membrane ion channels and transporters, which will further fulfill our understanding of pharmacology of PKA inhibitors.Methods Whole-cell patch clamp was used to investigate the effects of H-89 on cardiac L-type Ca~(2+) current (I_(Ca-L)), Na~+ current (I_(Na)), inward rectifier K~+ current (I_(K1)), transient outward K~+ current (I_(to)) and Na~+-Ca~2+ exchanger current (I_(Na/Ca)) in enzymatic dissociated SD rat ventricular myocytes.Results H-89 at 1～10 μmol·L~(-1) could inhibit I_(Ca-L) , I_(Na) , and Ito in a concentration-relative manner (P <0.05). At low concentra-tion (5 μmol·L~(-1)), H-89 completely inhibited I_(K1) (P <0.05) just as the action of 0.5 mmol·L~(-1) BaCl_2.Further, H-89 at 1～10 μmol·L~(-1) had no significant effect on I_(Na/Ca) (P >0.05).Conclusion The direct or PKA-mediated indirect action maybe involved in the effects of H-89 on ion currents and transporter.