Non-thermal microwave radiation-induced brain tissue dehydration as a potential factor for brain functional impairment

Based on our previous finding that metabolically controlled cell hydration is sensitive to the changes of physicochemical properties of cell aqua medium, which take place upon the effect of weak physical signals, including microwaves with non-thermal intensity (NT MW), it has been hypothesized that cell aqua medium serves as a primary target for NT MW effect on brain tissue. To elucidate the nature of the metabolic pathway through which the effect of NT MW-induced changes of physicochemical properties of cell aqua medium modulate cell hydration, the effects of intraperitoneal (IP) injection of PS treated by NT MW on brain tissue hydration, 45Ca2+ uptake, [3H]-ouabain binding with cell membrane and intracellular cyclic nucleotides have been studied. The obtained data indicate that PS treated by NT MW through the activation of high affinity ouabain receptors in membrane stimulates cAMP-dependent Na+/Ca2+ exchange in reverse mode (R), which leads to brain tissue hydration in healthy (young) and dehydration in non-healthy (old) rats. As NT MW radiation-induced activation of R Na+/Ca2+ exchange leads to the increase of intracellular Ca2+ ([Ca2+]i), it is considered as a potential factor leading to the brain functional impairment, especially when brain metabolic activity is depressed (e.g. during aging).