Matucci R, Ottaviani M F, Campana S, Bianchi B, Bennardini F, Moneti G, Giotti A, Franconi F
Dip. Farmacologia Preclinica e Clinica, Università di Firenze, Italia.
Pharmacol Res. 1992 Sep;26(2):151-9. doi: 10.1016/s1043-6618(05)80128-8.
The incubation of xanthine-oxidase (XOD) with rat cardiac membranes induced the formation of free radicals; they were identified by electron spin resonance spectroscopy (ESR) studies using 0.1 M 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) for spin-trapping. The following DMPO adducts were measured: DMPO-OH, which was produced during the first minute of incubation, DMPO-R radicals, which were present after 4 min of incubation and where the signal intensity remained constant for at least 20 min. The binding studies performed after 15 min incubation showed that XOD (1-50 mU) dose dependently reduced 3H-nitrendipine binding. This reduction was caused by a decrease in the density of binding sites while the affinity remained unchanged. These results suggest that ethoxy radical formation may be an important step in the regulation of L type calcium channels.
黄嘌呤氧化酶（XOD）与大鼠心肌膜温育可诱导自由基的形成；通过电子自旋共振光谱（ESR）研究，使用0.1 M 5,5-二甲基-1-吡咯啉-1-氧化物（DMPO）进行自旋捕获来鉴定这些自由基。测定了以下DMPO加合物：温育第一分钟产生的DMPO-OH，温育4分钟后存在的DMPO-R自由基，其信号强度至少在20分钟内保持恒定。温育15分钟后进行的结合研究表明，XOD（1 - 50 mU）剂量依赖性地降低3H-尼群地平结合。这种降低是由于结合位点密度降低，而亲和力保持不变。这些结果表明乙氧基自由基的形成可能是L型钙通道调节中的一个重要步骤。
