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We studied the functionality of the antioxidant system in laboratory rat cardiomyocytes and blood under psychoemotional stress. It was found that 40-day isolation and violation of diurnal cycle among the animals were accompanied by the intensification of lipid peroxidation process and marked with a reduced activity of antioxidant system enzymes, such as catalase and superoxide dismutase activity. The results suggested that psycho-emotional stress was accompanied by oxidative stress, causing a reduction in the intensity of energy metabolism in cardiomyocytes, which was further strengthened by the fact that the activity of the enzymes involved in ATP synthesis in mitochondria was reduced. Based on the results, we proposed that psychological stress is one of the factors contributing to the development of various cardiac diseases.

We have studied the influences that prolonged isolation and disruption of the circadian cycle have on behavioral activity and hormonal status among animals. It has been showed that such conditions result in development of stress, and decreases occur in the activity of both isoforms of rat hippocampus creatine kinase (CK). We have established kinetic parameters (V max , K m ) of this hippocampal enzyme and the nature of the modifications produced by the protocol. It has been suggested that prolonged isolation and disrupted natural circadian cycle result in lower CK-BB activity in animals due to structural changes in the enzyme and a decrease in ATP and creatine substrates. Lowered enzyme activity is accompanied by an accumulation of Ca 2+ ions in the cell, and this might decrease activity of plasma membrane and mitochondrial Ca-ATPase.

We have experimentally demonstrated that the emission of visible light from the polymer matrix doped with luminescent dye and gold nanoparticles (GNPs) can be enhanced with the use of surface plasmon coupling. GNPs can enhance the luminescence intensity of nearby luminescent dye because of the interactions between the dipole moments of the dye and the surface plasmon field of the GNPs. The electric charge on the GNPs and the distance between GNPs and luminescent dye molecules have a significant effect on the luminescence intensity, and this enhancement depends strongly upon the excitation wavelength of the pumping laser source. In particular, by matching the plasmon frequency of GNPs to the frequency of the laser light source we have observed a strong luminescence enhancement of the nanocomposite consisting of GNPs coupled with luminescent dye Nile blue 690 perchlorate. This ability of controlling luminescence can be beneficially used in developing contrast agents for highly sensitive and specific optical sensing and imaging. This opens new possibilities for plasmonic applications in the solar energy field.

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