[The electrical activity of symmetrical areas of the rat cerebral cortex during the use of a low-intensity UHF field]. / Elektricheskaia aktivnost' simmetrichnykh oblastei kory golovnogo mozga krys pri ispol'zovanii SVCh-polia nizkoi intensivnosti.

Electrical asymmetry of electrograms of the rat symmetrical brain areas was decreased under the UHF irradiation of the animals. Non-modulated UHF field increased the 1.5 and 6 Hz rhythms in the left hemisphere, whereas modulated UHF field decreased the 1 Hz rhythm in the right hemisphere. The effects were only occurring at the initial period of the UHF fields use.

[Changes in the electrical activity of the rat brain during the central administration of different doses of GABA agonists and antagonists]. / Izmeneniia élektricheskoi aktivnosti mozga krys pri tsentral'nom vvedenii razlichnykh doz agonistov i antagonistov GAMK.

The changes in the frequency content of electrograms of the optic cortical area and deep structures of the brain (putamen, dorsal hippocampus, medial part of the hypothalamus) were studied during intraventricular introduction of various doses of GABA-receptor agonists (GABA, muscimol, baclofen) and antagonist (bicuculline). The latter was found to affect the overall electrical activity slightly regardless of the dose. When muscimol and baclofen were injected, the greatest EG effect was observed at 1.10(-9) mole. A dose-dependent reversion of EG effects was revealed for GABA and muscimol; at the alpha-range 1.10(-6) mole, of GABA was found to weaken rhythmic activity, while 1.10(-8) mole of muscimol increased and 1.10(-9) mole decreased the power of alpha-rhythm. The correlation analysis of EG changes suggests that there is one interdependent mechanism or more for formation of EG of the range studied which operate by the starting mechanism.

[The electrical activity of the hypothalamus in exposure to millimeter-wave radiation at biologically active points]. / Elektricheskaia aktivnost' gipotalamusa pri vozdeistvii millimetrovym izlucheniem na biologicheski aktivnye tochki.

In chronic experiments on awake rabbits, the exposure of the auricular "heart" point (after F. G. Portnov) by nonthermal local millimeter wave irradiation (55-76 GHz range) yielded a significant suppression of hypothalamic electrical activity at 5 and 16 Hz and enhancement at 7-8, 12 and 26 Hz. The exposure of the cranial acupoint (TR-20) (the "hypothalamus" point after R. Voll) gave similar though less prominent results at 7-8 and 12 Hz. Minimal changes in electrogram were observed when the acupoint of "longevity" (E-36) was exposed.

[Brain electric activity of animals exposed to perfluorocarbon emulsions]. / Elektricheskaia aktivnost' mozga zhivotnykh v usloviiakh primeneniia perftoruglerodnykh émul'sii.

Experiments were conducted on animals with chronically implanted electrodes in the brain to study the frequency composition of its electrical activity in normovolemic replacement of blood with a carbon pertetrafluoride emulsion "Perftoran" (11 rats), and in plethoric intravenous (7 rabbits) and intracerebral (5 rats) injections of this preparation. Marked reactions were encountered in the initial period after Perftoran administration (up to 4-8 hours in transfusions and 0-5 minutes in intravascular and intracerebral infusions).

Electrical activity of the visual cortex under conditions of change in the levels of monoamines in the brain of animals.

The changes in the electrograms of the visual cortex of awake animals under the influence of light stimulation in conditions of a pharmacological effect on the monoamine (MA) systems of the brain were investigated in experiments on 8 rabbits and 12 rats. The following was found following the administration of MA precursors (5-hydroxytryptophan and d,l-dihydroxyphenylalanine): a) a decrease in the amplitude of the averaged evoked potentials in response to rhythmical light stimuli (1-20 pulses/sec); b) intensification of rapid (15-25 Hz) oscillations in the spontaneous electrical activity of the cortex, as well as attenuation and modification of the effects of the blocker of MA synthesis, a-methyl-dihydroxyphenylalanine. A potentiation of the MA precursors was observed with light stimulation in the frequency spectra of the electrocorticograms. The specific characteristics of the action of the catecholamine precursor were manifested in the same conditions in the form of an intensification of the power of the 5-7 Hz rhythms, and an attenuation of the power of the 2-3 Hz rhythms.

Electrical activity of the hippocampus of rats with the central administration of GABA agonists and antagonists.

The frequency spectra of the electrograms of the dorsal hippocampus with intraventricular administration of GABA, muscimol, baclofen, bicuculline, and picrotoxin, were studied in chronic experiments on 24 awake freely-moving rats. The data obtained are in accord with the existing notion regarding the interactions of agonists and antagonists with GABA receptors. The possibility of their participation in the formation and/or modulation of the total electrical activity of the hippocampus is discussed.

[Electrical activity of the visual cortex under conditions of altered monoamine levels in the brain of animals]. / Elektricheskaia aktivnost' zritel'noi kory v usloviiakh izmeneniia urovnei monoaminov v mozge zhivotnykh.

In experiments on 8 rabbits and 12 rats changes in electrograms of the visual cortex of alert animals were studied under photic stimulation in conditions of pharmacological action on monoamine (MA) brain systems. After injection of MA precursors (5-oxitriptophane and d, 1-dioxiphenylalanine) following phenomena were observed: a) decrease of the amplitude of the averaged evoked potentials to rhythmic photic stimuli (1-20 imp. sec.-1); b) an enhancement of fast (15-25 Hz) oscillations in the cortical spontaneous electrical activity and weakening and modification of the effects of the blockader of synthesis of MA-alpha-methyl-dioxiphenylalanine. Under light stimulation potentiation of MA precursors effects was observed in the frequency spectra of electrocorticograms. In the same conditions the specificity of action of cathecholamines precursor was revealed in the form of an increase of power of rhythms of 5-7 Hz and it; decrease in 2-3 Hz. Possible mechanisms of the revealed phenomena are discussed.

[The electrical activity of the hippocampus in rats centrally administered GABA agonists and antagonists]. / Elektricheskaia aktivnost' gippokampa krys pri tsentral'nom vvedenii agonistov i antagonistov GAMK.

In unrestrained rats, frequency ranges of dorsal hippocampus electrograms were studied after intraventricular injections of the GABA, muscimol, baclofen, bicuculline and picrotoxin. The data obtained corroborates the idea of an interrelationship between the agonists and antagonists of the GABA receptors. A possibility of participation of these receptors in the formation and/or modulation of total electrical hippocampal activity, is discussed.

[Frequency spectrum analysis of the electrical activity of the brain in the rat as affected by ketamine]. / Chastotnyi spektral'nyi analiz élektricheskoi aktivnosti golovnogo mozga krys pri deistvii ketamina.

The effect of ketamine (80 mg/kg, intraperitoneally) on the frequency composition of electrograms of the visual and somatosensory regions of the cerebral cortex, hippocampus and medial nuclei of the hypothalamus was studied in chronic experiments on rats. An increase of the power of 4 Hz fluctuations and a decrease of 6 Hz fluctuations were noted in all structures. Ten min. after the drug injection the effect of 4 Hz rhythm enhancement was sharply suppressed (except the visual cortex). A combined administration of 5-hydroxytryptophan (30 mg/kg) and alpha-methyl-dihydroxyphenylalanine (100 mg/kg) resulted in the occurrence on the visual cortex of the effects similar to those produced by ketamine.