Inhibition by nitrendipine of 86Rb+ fluxes in subconfluent MDCK cells

The osmotic resistance, and zeta potential responses of human erythrocytes to transmembrane modification of Ca2+ fluxes in the presence of the imposed low rate radiation field of 90Sr

PURPOSE

To investigate the effects of the imposed low dose rate ionizing field on membrane stability of human erythrocytes under modulation of transmembrane exchange of Ca(2+).

MATERIALS AND METHODS

Osmotic resistance of human erythrocytes was determined by a measure of haemoglobin released from erythrocytes when placed in a medium containing serial dilutions of Krebs isotonic buffer. The zeta potential as indicator of surface membrane potential was calculated from value of the cellular electrophoretic mobility. The irradiation of erythrocyte suspensions carried out by applying suitable aliquots of (90)Sr in incubation media.

RESULTS

Irradiation of human erythrocytes by (90)Sr (1.5-15.0 μGy·h(-1)) induced a reversible increase of hyposmotic hemolysis and negative charge value on the outer membrane surface as well as changed responses these parameters to modification of Ca(2+) fluxes with calcimycin and nitrendipine.

CONCLUSIONS

Findings indicate that the low dose rate radionuclides ((90)Sr) field modifies both Ca(2+)-mediated, and Ca(2+)-independent cellular signalling regulating mechanical stability of erythrocyte membrane. A direction of that modification presumably depends on the initial structure of membranes, and it is determined by the quality and quantitative parameters of changes in membrane structure caused by concrete operable factors.