Biomedical subjects

V V Vorobyov

Publications and source records attributed to V V Vorobyov.

3 recordsLinked to original sources

PubMed1998

Muscarinic elicitation of EEG asymmetry in freely moving rats.

Averaged frequency spectra (0.5-30 Hz) of electroencephalogram (EEG) were studied in six freely moving rats with chronically implanted electrodes in symmetrical areas of somatosensory cortex. Hemispheric asymmetry in spectra of an ongoing EEG was expressed as a power decrease in 15.6-17.2 Hz band on the left hemisphere and as that in 25.2-27.8 Hz band on the right one. Physostigmine subcutaneous (s.c.) injection (0.25 mg/kg) provoked appearance of the significant left brain bias in 4.7-8.6 Hz range of EEG spectra and the right brain bias in 19.3-21.3 Hz band. These physostigmine effects were counteracted by scopolamine (1.5 mg/kg, s.c.) injected 30 min before. It is suggested that a muscarinic component may be involved in the interhemispheric cooperation associated with cortical theta activity in rats.

Animals↗

PubMed1998

Weak combined magnetic field affects basic and morphine-induced rat's EEG.

The present study was undertaken to find out, whether weak combined magnetic field (CMF) with intensity comparable to that of the Earth's static 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 cannules. Most of the experiments were performed using CMF containing co-linear static (20.9 microT) and alternating sinusoidal (20.9 microT, 48 Hz) components, i.e., tuned for Ca2+-resonance. The effects of the field were estimated by comparison of the averaged EEG frequency spectra in the range of frequencies between 0.8-23 Hz in experimental and control animals. Statistically significant effects of CMF were observed both in non-treated and morphine-treated rats. However, the most profound effect-the drastic power reduction at most EEG frequencies-appeared in the animals subjected to the i.p.-injection of morphine. These results show that weak CMF can influence the spontaneous electrical brain activity. The data obtained are consistent with the findings of other groups demonstrating that weak magnetic fields may drastically modify the effects of both exogenous and endogenous opioids on different basic functions in vertebrates and invertebrates. Possible mechanisms for the observed effects are discussed.

Analgesics, Opioid↗

PubMed1997

Effects of weak microwave fields amplitude modulated at ELF on EEG of symmetric brain areas in rats.

Averaged electroencephalogram (EEG) frequency spectra were studied in eight unanesthetized and unmyorelaxed adult male rats with chronically implanted carbon electrodes in symmetrical somesthetic areas when a weak (0.1-0.2 mW/cm) microwave (MW, 945 MHz) field, amplitude-modulated at extremely low frequency (ELF) (4 Hz), was applied. Intermittent (1 min "On," 1 min "Off") field exposure (10-min duration) was used. Hemispheric asymmetry in frequency spectra (averaged data for 10 or 1 min) of an ongoing EEG was characterized by a power decrease in the 1.5-3 Hz range on the left hemisphere and by a power decrease in the 10-14 and 20-30 Hz ranges on the right hemisphere. No differences between control and exposure experiments were shown under these routines of data averaging. Significant elevations of EEG asymmetry in 10-14 Hz range were observed during the first 20 s after four from five onsets of the MW field, when averaged spectra were obtained for every 10 s. Under neither control nor pre- and postexposure conditions was this effect observed. These results are discussed with respect to interaction of MW fields with the EEG generators.

Animals↗