[Interaction of vasoactive substances with phospholipid and erythrocyte membranes]

Experiments with phospholipid liposomes, red cells (or their shades) of man and pigeon, modulated with helium-neon laser, were made to study the effects of papaverine, verapamil, phosphadene, theophylline, nicotinic acid, acetylcholine, adenosine and hydralazine on the intensity of the own fluorescence of the membrane and of the membrane-bound probe, 1,8-AHC, segregation of methylene blue by the red cell mass, red cell resistance to osmotic or UV-induced hemolysis as well as on the activity of Na-, K-, Mg- and Ca-dependent ATPases of the red cell shades of the donor or pigeon. As regards the tests used, the most differentiated membranous effects were discovered for the drugs under study within the concentration range 10(-5)-10(-8) M. The vasoactive agents administered at equimolar end concentrations produced quantitatively and qualitatively inconsistent effects on the parameters tested. They increased (with the exception of acetylcholine) segregation of the cationic dye, reduced the fluorescence intensity of the probe, and elevated the resistance to osmotic and UV-induced hemolysis. The latter circumstance is likely to be determined by activation of membranous ATPases. Exposure to laser potentiated the membrane-stabilizing action of the substances under consideration.