Influence of alternating low frequency magnetic fields on reactivity of central dopamine receptors in neonatal 6-hydroxydopamine treated rats

The aim of this study was to evaluate the influence of extremely low freque ncy magnetic field (ELF MF) on the reactivity of the central dopamine D-1 r eceptor in rats with dopamine neurons chemically damaged by 6-hydroxydopami ne (6-OHDA), an animal model of human's Parkinson's disease. The experiment was carried out on male Wistar rats. On day 3 of postnatal life, a lasting and selective chemical damage of the central dopamine system was induced i n the rats by infusion of 6-OHDA HBr (133.4 mug intracerebroventricular, ba se form) given bilaterally into lateral ventricles of the brain. Control an imals received similar treatments injecting only vehicle. At 2 months of ag e, both 6-OHDA treated and control rats were randomly divided into two grou ps. Rats from the first group were exposed to 10 Hz sinusoidal, 1.8-3.8 mT magnetic field one hour daily for 14 days. Rats of the second group were sh am exposed, with the applicator solenoid tamed off. On the day after the fi nal exposure the evaluations were made of the rat's spontaneous irritabilit y, oral activity, and catalepsy. The MF exposed rat with chemically induced dopamine neurons damage exhibited a reduction of irritability and oral act ivity when stimulated with SKF 38393 (the agonist of central dopamine D-1 r eceptor) and some increase of catalepsy after administration of SCH 23390 ( the antagonist of central doparnine D-1 receptor). These results indicate t hat ELF MF reduce the reactivity of central dopamine D-1 receptors in rats. (C) 2001 Wiley-Liss, Inc.