Effects of Ca2+ channel blockers on store-operated Ca2+ channel currents of Kupffer cells after hepatic ischemia/reperfusion injury in rats

Abstract

Aim: To study the effects of hepatic ischemia/reperfusion (I/R) injury on store-operated calcium channel (SOC) currents (I(SOC)) in freshly isolated rat Kupffer cells, and the effects of Ca(2+) channel blockers, 2-aminoethoxydiphenyl borate (2-APB), SK and F96365, econazole and miconazole, on I(SOC) in isolated rat Kupffer cells after hepatic I/R injury.

Methods: The model of rat hepatic I/R injury was established. Whole-cell patch-clamp techniques were performed to investigate the effects of 2-APB, SK and F96365, econazole and miconazole on I(SOC) in isolated rat Kupffer cells after hepatic I /R injury.

Results: I/R injury significantly increased I(SOC) from -80.4 +/- 25.2pA to -159.5 +/- 34.5pA ((b)P < 0.01, n = 30). 2-APB (20, 40, 60, 80, 100 micromol/L), SK and F96365 (5, 10, 20, 40, 50 micromol/L), econazole (0.1, 0.3, 1, 3, 10 micromol/L) and miconazole (0.1, 0.3, 1, 3, 10 micromol/L) inhibited I(SOC) in a concentration-dependent manner with IC50 of 37.41 micromol/L (n = 8), 5.89 micromol/L (n = 11), 0.21 micromol/L (n = 13), and 0.28 micromol/L (n = 10). The peak value of I(SOC) in the I-V relationship was decreased by the blockers in different concentrations, but the reverse potential of I(SOC) was not transformed.

Conclusion: SOC is the main channel for the influx of Ca(2+) during hepatic I/R injuries. Calcium channel blockers, 2-APB, SK and F96365, econazole and miconazole, have obviously protective effects on I/R injury, probably by inhibiting I(SOC) in Kupffer cells and preventing the activation of Kupffer cells.

Figure 1

Whole-cell currents measured at the test potential from -120 mV to + 80 mV in sham-operated control (A) and in rats with ischemia/reperfusion injuries (B).

Figure 2

I-V curve of whole-cell currents measured at -100 mV test potential. ^bP < 0.01 vs sham-operated control (●) (▲ I/R).

Figure 3

I-V curve of whole-cell currents at -100 mV test potential affected by 2-APB