The reason for hyper magnetosensitivity of young animals compared to older ones remains unclear. It has been suggested that age-induced tissue dehydration (decreased water content) could be a basis for the aging-related decrease in the organism's magnetosensitivity. To test this hypothesis, the effect of a 0.2 T static magnetic field (SMF) exposure on heart muscle hydration in three age groups of rats (young, adult, and older) was studied, with and without ouabain poisoning. The SMF exposure resulted in heart muscle dehydration of young (21%) and adult (6.2%) rats but had no effect on older animals. In young animals without ouabin poisoning, SMF exposure caused dehydration of the heart muscle while in the ouabain-poisoned animals it led to hydration (29.6%). These hydration effects were more pronounced in young animals than in adult and older animals. The increased hydration (5.7%) of heart muscles in older animals was evoked by providing distilled water for seven days, which elevated (by 12%) the SMF-induced heart muscle hydration effect. These results suggest that the hyper magnetosensitivity of the young heart muscle and the lower sensitivity of older animals are due to initial high (83.5%) and low (75.3%) tissue hydration levels, respectively. Therefore, the age-induced decrease in the magnetosensitivity of heart muscle is likely to be a result of Na(+)/K(+) pump dysfunction.

The comparative study of the effects of 5.8 mW/cm(2) Millimeter Waves (MMW) and near Infrared (IR) irradiation on thermal properties, specific adsorption rate (SAR), specific electrical conductivity (SEC) and hydrogen peroxide (H(2)O(2)) content of distilled water (DW), and physiological solutions (PS) was performed. The thermal effect of MMW irradiation appeared only after the first minute of irradiation, while the IR heating started from the first minute of irradiation. The heat fusion of frozen MMW-treated DW and PS was significantly less than sham and IR-treated DW and PS. MMW irradiation had time-dependent elevation effect on water SEC and SAR, which was accompanied by the increase of H(2)O(2) formation in it. We suggest that the MMW-induced vibration of water dipole molecules caused the non thermal changes of physicochemical properties of DW and PS, which promote the formation of H(2)O(2) in water.

The effect of magnetized physiological solution (MPS) on isolated, perfused snail heart muscle contractility, (45)Ca uptake and intracellular level of cAMP, and cGMP was studied. The existence of the relaxing effect of MPS on heart muscle at room temperature (22 degrees C) and its absence in cold medium (4 degrees C) was shown. The MPS had a depressing effect on (45)Ca uptake by muscles and intracellular cAMP content and an elevating effect on intracellular cGMP level. It is suggested that the relaxing effect of MPS on heart muscle is due to the decrease of intracellular Ca ions as the result of activation of cGMP-dependent Ca efflux. The MPS induced decrease of intracellular cAMP content can be considered as a consequence of intracellular Ca loss, leading to the Na + K-ATPase reactivation, and causing the decrease of the intracellular level of ATP, serving as a substrate and positive modulator of cyclase activity.

In our previous work we have shown that the age-dependent decrease in the magnetosensitivity of heart muscle hydration is accompanied by a dysfunction of the Na(+) /K(+) pump. The reciprocal relation between the Na(+/) K(+) pump and Na(+) /Ca(2+) exchange in development was suggested as a possible pathway for the age-dependent decrease in the magnetosensitivity of heart muscle hydration (water content). Because high and low affinity ouabain receptors in cell membranes are involved in Na(+) /Ca(2+) exchange and Na(+) /K(+) pump functions, respectively, the effect of a 0.2 T static magnetic field (SMF) on dose-dependent, ouabain-induced hydration and [(3) H]-ouabain binding with heart muscle tissues in young, adult and older rats was studied. Three populations of receptors in membranes with high (10(-11) -10(-9)  M), middle (10(-9) -10(-7)  M) and low (10(-7) -10(-4)  M) affinity to [(3) H]-ouabain were distinguished, which had specific dose-dependent [(3) H]-ouabain binding kinetics and effects on muscle hydration. The magnetosensitivity of [(3) H]-ouabain binding kinetics with high affinity receptors was prominent in all the three age groups of animals, while with low affinity receptors it was more expressed only in the young group of animals. All three types of receptors that caused modulations of muscle hydration were age dependent and magnetosensitive. Based on the obtained data we came to the conclusion that heart muscle hydration in young animals is more magnetosensitive due to the intense expression of high affinity ouabain receptors, which declines with aging.

It was shown that the 4 Hz 30 dB mechanical vibration (MV) of physiological solution (PS) had modulation effect on snail heart contractility. However, the nature of metabolic pathway of MV-treated PS-induced effect is not clear yet. It was suggested that the MVinduced modulation of water molecules dissociation leads to the variation of reactive oxygen species' level in cell bathing medium, which could serve as a messenger for switching on the metabolic pathway(s) responsible for modulation of muscle contractility. The aim of present work was to check this hypothesis and to elucidate the metabolic pathway through which the effect of MV-treated PS on heart contractility was realized. For this purpose, the effect of MV on heat fusion periods (HFP) and H 2 O 2 content in PS, as well as on heart contractility, 45 Ca 2? efflux, intracellular levels of cGMP and cAMP, muscle hydration, and ouabain binding were studied. It was shown that MV treatment of PS increased the HFP-(21.33 ± 4%) and decreased the H 2 O 2 content-(5 ± 0.9%). The intracardiac perfusion by MV-treated PS increased the amplitudes of heart contractility, which was accompanied by the increasing of 45 Ca 2? efflux (252.4 ± 16%), elevation of cGMP's level (42.05 ± 7%), decreasing of cAMP's level (82.67 ± 7%), increasing of the tissue hydration (18.64 ± 3%), and increasing of the number of ouabain binding sides (25 ± 4%). It was suggested that MVinduced increasing of heart muscle contraction amplitudes is due to the decreases of H 2 O 2 content in the medium, which leads to the elevation of heart muscle contractility in result of activation of cGMP-dependent Na ? /Ca 2? exchange in forward regime.