Varani Katia, Gessi Stefania, Merighi Stefania, Iannotta Valeria, Cattabriga Elena, Spisani Susanna, Cadossi Ruggero, Borea Pier Andrea
Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Ferrara, Italy.
Br J Pharmacol. 2002 May;136(1):57-66. doi: 10.1038/sj.bjp.0704695.
The present study describes the effect of low frequency, low energy, pulsing electromagnetic fields (PEMFs) on A2A adenosine receptors in human neutrophils. Saturation experiments performed using a high affinity adenosine antagonist [3H]-ZM 241385 revealed a single class of binding sites in control and in PEMF-treated human neutrophils with similar affinity (KD=1.05+/-0.10 and 1.08+/-0.12 nM, respectively). Furthermore, after 1 h of exposure to PEMFs the receptor density was statistically increased (P<0.01) (Bmax =126+/-10 and 215+/-15 fmol mg-1 protein, respectively). The effect of PEMFs was specific to the A2A adenosine receptors. This effect was also intensity, time and temperature dependent. In the adenylyl cyclase assays the A2A receptor agonists, HE-NECA and NECA, increased cyclic AMP accumulation in untreated human neutrophils with an EC50 value of 43 (40 - 47) and 255 (228 - 284) nM, respectively. The capability of HE-NECA and NECA to stimulate cyclic AMP levels in human neutrophils was increased (P<0.01) after exposure to PEMFs with an EC50 value of 10(8 - 13) and 61(52 - 71) nM, respectively. In the superoxide anion (O2-) production assays HE-NECA and NECA inhibited the generation of O2- in untreated human neutrophils, with an EC50 value of 3.6(3.1 - 4.2) and of 23(20 - 27) nM, respectively. Moreover, in PEMF-treated human neutrophils, the same compounds show an EC50 value of 1.6(1.2 - 2.1) and of 6.0(4.7 - 7.5) nM respectively. These results indicate the presence of significant alterations in the expression and in the functionality of adenosine A2A receptors in human neutrophils treated with PEMFs.
本研究描述了低频、低能量脉冲电磁场（PEMFs）对人中性粒细胞中A2A腺苷受体的影响。使用高亲和力腺苷拮抗剂[3H]-ZM 241385进行的饱和实验显示，在对照和经PEMF处理的人中性粒细胞中存在单一类别的结合位点，其亲和力相似（KD分别为1.05±0.10和1.08±0.12 nM）。此外，暴露于PEMFs 1小时后，受体密度有统计学意义的增加（P<0.01）（Bmax分别为126±10和215±15 fmol mg-1蛋白质）。PEMFs的作用对A2A腺苷受体具有特异性。这种作用还与强度、时间和温度有关。在腺苷酸环化酶测定中，A2A受体激动剂HE-NECA和NECA可增加未处理人中性粒细胞中环状AMP的积累，其EC50值分别为43（40 - 47）和255（228 - 284）nM。暴露于PEMFs后，HE-NECA和NECA刺激人中性粒细胞中环状AMP水平的能力增强（P<0.01），其EC50值分别为10（8 - 13）和61（52 - 71）nM。在超氧阴离子（O2-）产生测定中，HE-NECA和NECA可抑制未处理人中性粒细胞中O2-的产生，其EC50值分别为3.6（3.1 - 4.2）和23（20 - 27）nM。此外，在经PEMF处理的人中性粒细胞中，相同化合物的EC50值分别为1.6（1.2 - 2.1）和6.0（4.7 - 7.5）nM。这些结果表明，经PEMFs处理的人中性粒细胞中腺苷A2A受体的表达和功能存在显著改变。
