S.M. Minasyan
Dr. Sc. (Biol.), Professor, Liading Research Scientist, Department of Yuman and Animals Physiology,
Erevan State University (Armenia)
G.Yu. Grigoryan
Ph.D. (Biol.), Research Scientist, Albert-Ludwigs University (Fleiburg, Germany)
E.S. Gevorkyan
Ph.D. (Biol.), Associate Professor, Research Scientist, Department of Human and Animals Physiology, Erevan State University (Armenia)
E-mail: Esgevorkyan@yandex.ru
Ts.I. Adamyan
Ph. D. (Biol.), Associate Professor, Senior Research Scientist, Department of Human and Animals Physisology,
Erevan State University (Armenia)
E-mail: Tsovinar.Adamyan@ysu.am
S.G. Sarkisyan
Dr. Sc. (Biol.), Senior Research Scientist, Department of Human and Animals Physisology,
Erevan State University (Armenia)
E-mail: Susanna_Sarkisyan@rambler.ru

One of the factors capable of limiting several pathological factors development in organism is low-intensity electromagnetic radiation (LER) of extremely high frequency (EHF) or millimeter range. It is known that different structures of the central nervous system have the greatest reactivity to LER action. The effectiveness of EHF impact on organism was established via acupuncture zones or biologically active points which are realized in general via supra-optic nucleus (SON) of hypothalamus. There is no enough evidence of mechanisms of LER impact on organism, particularly on nervous system. To address this, we carried out an electrophysiological analysis of the parameters of impulse activity (IA) of SON neurons of white rats in norm and different (one-time, 5-, 10-, 15- and 30-day) exposure of LER EHF of low intensity.

Abduction of impulse activity was carried out under Nembutal anesthesia using the method of extracellular registration with the help of glass microelectrodes. After the experiments, a histological verification of the localization of the electrodes was carried out. The registration and analysis of impulse activity of the neurons of SON were carried out with help of a computer program specially designed for recording biological signals. Sequential sections of interimpulse intervals (MI), including up to 1200 action potentials, were analyzed. The animals were radiated with G4-141 generator. Two different radiation frequencies were used – 42.2 GHz and 50.3 GHz. The average exposure value for a single exposure was 40 minutes from a distance of 40 cm from the horn of the radiator. The intensity of values changes of the average pulse frequency in different frequency ranges after exposure to electromagnetic radiation was determined by the White criterion.

Investigation of neuronal IA of the SON of hypothalamus using the above mentioned methods of analysis made it possible to determine the regularity, dynamic structure, modality, frequency distribution of the recorded impulse flows, as well as their statistical characteristics in the norm and after exposure to physical factors of different duration and modes of influence.

As a result of a single exposure to a low-intensity EHF LER the changes in the IA were revealed, mainly concerning the internal structure of the recorded impulse flows, in particular, the degree of regularity and the nature of the dynamics of the MI sequence. Investigating the effects in the dynamics of the 30-day exposure of the electromagnetic factor showed changes in neuronal activity related to both the internal structure and the statistical indicators of impulse activity.

Thus, a comparative analysis of changes in the parameters of the impulse activity of supraoptic neurons showed their sensitivity to a single exposure to nonthermal LER. Moreover, irradiation at a frequency of 42.2 GHz in comparison with the frequency of 50.3 GHz leads to more pronounced shifts in the IA of neurons. Prolonged exposure of EHF LER affects both the internal structure of impulse flows, and the statistical parameters of background activity. The significant reduction in the number of cells with a burst-group activity observed in the dynamics of long-term radiation, a decrease in the average discharge frequency, and an increase in the variability of pulsed neuronal fluxes in the SON allow us to conclude that the effect of LER is inhibitory and depends on the duration of the exposure.

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