He-Ne laser radiation effects on membrane fluidity of young and old human erythrocytes

Integral blood as well as young and old erythrocyte suspensions were irradiated using a low power He-Ne laser beam (633 nm, 3 mW). The effects produced on tile membrane fluidity of erythrocytes were monitored using steady slate depolarization fluorescence measurements. Using integral blood we observed that there is a reversible increase of the membrane fluidity during irradiation. The recovery of the original fluidity values was quasi instantaneous relative to the time resolution of our method.