1,4-Dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylic
acid methyl 6-(5-phenyl-3-pyrazolyloxy)hexyl
ester (CV159) exhibits selective blocking of Ca(2+)/
calmodulin and inhibits Ca(2+) overloading in living organisms. The effects of this antagonist in mice with hepatic
ischemia-reperfusion injury were investigated using electron paramagnetic resonance imaging (EPRI) and ex vivo EPR (x-band EPR) techniques. The EPRI determined that the 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl half-life in CV159-treated mice was significantly shorter than that in untreated mice and was almost equal to that in the
sham group. Both the cytosolic and the mitochondrial
superoxide scavenging activities in CV-treated mice were significantly higher than that in untreated mice. Faint staining of the anti-
superoxide dismutase antibody and strong staining of anti-
inducible nitric oxide synthase antibody were observed in the liver of control group. In contrast to these findings, immunostaining of these
antibodies in the liver of CV159-treated mice were reversed compared to control group. Western blotting showed that CV159 contributed to the high
superoxide dismutase expression and low expression of
inducible nitric oxide synthase. The
alanine aminotransferase level in CV159-treated mice significantly decreased in comparison to that observed in the untreated mice. We conclude that CV159 retains its organ-reducing activity against radicals in hepatic
reperfusion injury, which is mediated by the inhibition of Ca(2+) overloading.