WEAK COMBINED MAGNETIC-FIELD AFFECTS BASIC AND MORPHINE-INDUCED RATS EEG

The present study was undertaken to find out, whether weak combined ma gnetic field (CMF) with intensity comparable to that of the Earth's st atic magnetic field can influence the EEG activity of the rat's brain at normal (non-treated animals) conditions and after intraperitoneal ( i.p.) and intracerebroventricular (i.c.v.) administration of morphine in experimental animals bearing chronically implanted electrodes and c annules. Most of the experiments were performed using CMF containing c o-linear static (20.9 mu T) and alternating sinusoidal (20.9 mu T, 48 Hz) components, i.e., tuned for Ca2+-resonance. The effects of the fie ld were estimated by comparison of the averaged EEG frequency spectra in the range of frequencies between 0.8-23 Hz in experimental and cont rol animals. Statistically significant effects of CMF were observed bo th in non-treated and morphine-treated rats. However, the most profoun d effect - the drastic power reduction at most EEG frequencies-appeare d in the animals subjected to the i.p.-injection of morphine. These re sults show that weak CMF can influence the spontaneous electrical brai n activity. The data obtained are consistent with the findings of othe r groups functions in vertebrates and invertebrates. Possible mechanis ms for the observed effects are discussed. (C) 1998 Elsevier Science B .V.