FUNCTIONING OF CARDIOVASCULAR SYSTEM OF LABORATORY RATS UNDER CONDITIONS OF SEASONAL FLUCTUATIONS IN ATMOSPHERIC PRESSURE AND GEOMAGNETIC AC- TIVITY
The aim of this work was analysis the relationship between seasonal fluctuations of atmospheric pressure and geomagnetic field and the hemodynamics parameters, and also spectrum components of heart rate variability in rats in standard laboratory conditions. Studies were conducted in Wistar male rats of the same age and belonging to the same population. Fall, winter, spring and summer systolic blood pressure (SBP) and beat-to-beat interval (RR) were registered, using tail-cuff method. Analysis of the spectrum of RR variability was conducted. Low frequency component (LF), high frequency (HF) and the ratio of the LF/HF components were calculated. Statistical analysis of atmospheric pressure, and geomagnetic field for 20 years for St. Petersburg was carried out. A decrease SBP in summer, increase LF/HF component spectrum of RR variability in winter and reducing HF component in the spring were registered. Clear seasonal dynamics of variability of atmospheric pressure was identified. A decrease of geomagnetic activity in winter has been established. It is shown, that the atmospheric pressure deviation from 755-756 mm Hg both upward and downward contributes to a rise of blood pressure. A direct relationship between the level of the SBP and the Ap index of geomagnetic activity was discovered. It was concluded, that seasonal dynamics of variability of atmospheric pressure and geomagnetic activity can cause the seasonal variations in the functioning of the cardiovascular system in rats, contained in standard laboratory conditions.