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Acta Medica Medianae
Correspondence to:
Institut za biohemiju Medicinskog fakulteta Bulevar Zorana Đinđića 81 18000 Niš, Srbija E-mail: soko@medfak.ni.ac.yu
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Original article
THE INFLUENCE OF Nω-NITRO-L-ARGININE METHYL ESTER ON ARGININE AND POLYAMINE METABOLISM IN RAT’S BRAIN TISSUE DURING EXPOSITION TO MICROWAVE RADIATION
Dusan Sokolovic, Boris Djindjic, Dejan Krstic, Dejan Petkovic, Vera Markovic, Jovica Jovanovic, Olivera Dunjic and Maja Jocic
Medicinski fakultet Univerziteta u Nišu1 Fakultet zaštite na radu Univerziteta u Nišu2 Elektronski fakultet Univerziteta u Nišu3
Exposition to microwave radiation (MW) from mobile phones, satellite communi-cations, radio relays, radars and microwave devices in medicine induce disturbances in different organ systems. It has been shown that MW from mobile phones induce increasing of oxidative stress and apoptosis of neurons with impairment of blood brain barrier, disturbances of memory and space orientation. Citrulline and nitric oxide -NO are products of L-arginine by NO sintase-NOS. L-ornithine and polyamines are products of L-arginine by arginase. Nω-nitro-L-arginine methyl ester (L-NAME) competitive inhibits NOS and exerts neuroprotective effects. The aim of this investigation was to determine the arginase, PAO and DAO activity, concentration of citrulline, as well as the effects of L-NAME on arginine and polyamine metabolism in brain tissue of rats exposed to MW. Four groups of Wistar rats were investigated during 60 days: I-control-sham exposed, II (L-NAME)-rats treated with L-NAME (5 mg/kg b.w. i.p.), III (MW)-rats exposed to MW (4 h/day), IV (MW + L-NAME). The source of MW was mobile test telephone. Decreasing activity of arginase (0.19±0.04 vs. 0.25±0.05 mmol/mg prot; p<0.01) and increasing of citrulline concentration (10.34±0.49 vs. 7.83 ±0.41 mmol/mg prot; p<0.001) were registered in the brain of MW exposed rats compared to controls. In L-NAME group there was a decrease of citrulline level (p<0.05), and increase in arginase activity (p<0.05) compared to controls. In the brain of exposed rats, the activity of PAO was significantly increased, while the activity of DAO was significantly increased vs. controls (1.12±0.10 vs. 0.79±0.09 U/mg prot; p<0.001 and 0.51±0.06 vs. 0.65±0.06 U/mg prot; p<0.05, prospectively). In MW+L-NAME group we registered increasing of DAO activity (0.61±0.04 vs. 0.51±0.06 U/mg prot; p<0.05) in the brain tissue compared with MW group. Having considered the obtained results we concluded that L-NAME exerted neuroprotective effects by preventing polyamine and arginine metabolism disturbances in the rats' brain under exposition to MW. Acta Medica Medianae 2009;48(1): 5-11.
Key words: L-NAME, microwave radiation, arginine, polyamine, brain |