TY - JOUR T1 - [Effect of KB-R7943 on Na(+)-Ca2+ exchange current in guinea pig ventricular myocytes]. AU - Lu,J, AU - Xu,X H, AU - Wang,X L, PY - 2003/2/13/pubmed PY - 2003/8/9/medline PY - 2003/2/13/entrez SP - 25 EP - 8 JF - Yao xue xue bao = Acta pharmaceutica Sinica JO - Yao Xue Xue Bao VL - 36 IS - 1 N2 - AIM: To study whether KB-R7943 has selective inhibitory effect on the inward and outward Na(+)-Ca2+ exchange current (INa-Ca) in guinea pig ventricular myocytes. METHODS: Through setting up the model of intracellular Na(+)-overload during myocardial ischemia and reperfusion, the current-voltage relationship of INa-Ca was recorded using whole-cell patch clamp technique under bi-directional ionic conditions. RESULTS: Currents were elicited by a declining ramp pulse depolarized immediately from holding potential of -40 mV to +60 mV, then repolarized to -100 mV at a speed of 80 mV.s-1 and returned to the holding potential under bi-directional ionic conditions, while the [Na+] was 25 mmol.L-1 in the pipette solution. The currents increased time-dependently and voltage-dependently which reached from (2.51 +/- 0.15) pA.pF-1 to (5.94 +/- 0.13) pA.pF-1 at mV and from (-1.92 +/- 0.13) pA.pF-1 to (-3.17 +/- 0.16) pA.pF-1 at -80 mV (n = 12) after 3 min and there is no significant run-down of the current. KB-R7943 10(-6) mol.L-1 was found to decrease the current to (4.62 +/- 0.05) pA.pF-1 by 29.4% at mV and to (-2.30 +/- 0.18) pA.pF-1 by 22.1% at -80 mV (n = 5) after 5 min. While 10(-5) mol.L-1 KB-R7943 was shown to decrease the current to (3.13 +/- 0.03) pA.pF-1 by 61.7% at mV and to (-1.62 +/- 0.03) pA.pF-1 by 56.9% at -80 mV (n = 7). CONCLUSION: KB-R7943 can block INa-Ca in guinea pig ventricular myocytes. But, it did not show selective inhibition effect on inward and outward currents. SN - 0513-4870 UR - https://www.unboundmedicine.com/medline/citation/12579855/[Effect_of_KB_R7943_on_Na_+__Ca2+_exchange_current_in_guinea_pig_ventricular_myocytes]_ DB - PRIME DP - Unbound Medicine ER -