Biochemical mechanisms of the energy-protective action of blockers of slow high-threshold L-type calcium channels

Abstract

This review discusses information about the structure and function of calcium channels in the plasma membrane and mitochondria of the heart, and pharmacological methods for modulating their conductance. Experimental data are presented that characterize the change in the energy metabolism of cardiomyocytes against the background of the transformation of the conductivity of L-type calcium channels of the cell membrane in a non-invasive model of vibration-mediated (56 sessions of total vertical vibration, with a frequency of 44 Hz and an amplitude of 0.5 mm) hypoxia. It was shown that in animals treated with calcium channel blocker adalat (nifedipine INN) against the background of vibration, the rate of endogenous respiration (Ve), measured by the polarographic method using a closed Clark electrode in native homogenate of rabbit myocardial tissue, remained at the level of intact animals and amounted to 16.3 4.3 ng-O atom/ min mg of protein, amytal sensitivity increased by 39% (p 0.05) compared to the group of vibrated animals, low-natality decreased by 40% (p 0.05). The dynamics of the rate of substrate respiration (Vac and Vglu + mal) in the group with adalat returned to that of intact animals, which indicated the restoration of the physiological predominance of the activity of theNADH CoQ-reductase complex in redox reactions. It was found that the blockade of transport of Ca2+ ions at the level of high-threshold (HVA) voltage-dependent ion channels of the L-type of the cell membrane, normalizing the activity of the I enzyme-substrate complex of the respiratory chain and regulatoryly restraining the hyperactivity of succinate dehydrogenase in zone II of the enzyme-substrate complex, has an energy-protective effect. Adalat prevented a low-energy shift and the development of bioenergetic hypoxia in the myocardial tissue of experimental animals.