INCREASE OF POTASSIUM AND CA2+-DEPENDENT POTASSIUM CONDUCTIVITY OF ERYTHROCYTES BY TETRAZOLIUM SALTS - EFFECT OF INHIBITORS OF ENERGETIC PROCESSES

The induction of potassium conductivity of human erythrocytes by tetrazolium salts monotetrazolium blue (CT) and m -nitrotetrazolium chloride in concentration 0,6 mM and 35 muM respectively was revealed. The K+ efflux increases in the presence of Ca2+ and inhibits by positively charged enzyme protamine sulphate. CT in concentration 0,2 mM doesn't affect the K+ transport. However, addition of CT after preliminary incubation of erythrocytes with protonophore ClCCP, electron transport inhibitor antimycin, anion transport inhibitor DIDS or anion detergent SDS leads to a sharp rise of K+ conductivity and hyperpolarization of membranes. Inhibitors of energetic processes oligomycin, DCC, antimycin and atebrin depress Ca2+-dependent K+ efflux induced CT combined with above mentioned compounds (except oligomycin and antimycin in the system SDS and CT). Atebrin inhibits DIDS and CT-stimulated Ca2+-dependent K+ efflux, reinforces total K+ efflux due to activation of K+,Cl- symport. It was proposed that cation permeability promotes owing to formation of complexes of tetrazolium salts with K+ and Ca2+ or (and) structural modification of erythrocytes membrane. The mechanisms of increase of K+ conductivity caused by CT in the presence of ClCCP, antimycin, DIDS and SDS and effects of inhibitors on K+ efflux are analysed.