Influence of beta-adrenoceptor blocking drugs on lipid-protein interaction in synaptosomal membranes. An ESR study

New systematically active antimycotics from the beta-blocker category

Candida albicans secretes phospholipases, which are considered to be one of the mediators of cell penetration. It is known that other phospholipases from mammalian cells can be inhibited by lipophilic beta-blocking structures. As the result of a synthesis programme of several years' duration, structures deriving from beta-hydroxyethylamines were introduced. In vitro and in vivo results with these compounds are presented in comparison with standard antimycotics. In combination with fluconazole, several of the compounds can prevent death in mice infected with lethal inocula of C. albicans. Histological examinations confirm the inhibitory effect of the beta-blocker-like structures on tissue penetration. The structures therefore constitute new antimycotics that are endowed with extensive in vitro effectiveness against fungi and also definite in vivo effects in the animal model.

Comparison of perturbation effect of propranolol, verapamil, chlorpromazine and carbisocaine on lecithin liposomes and brain total lipid liposomes. An EPR spectroscopy study

Effect of verapamil, propranolol, chlorpromazine and carbisocaine on dynamics and/or order of liposomes (perturbation effect), prepared from different molar ratios of lecithin (PC) and rat brain total lipids (TL) was studied by EPR spectroscopy using spin probes 16-doxyl stearic acid and 14-doxyl phosphatidylcholine. The PC liposomes had higher dynamics and/or lower order than the TL liposomes. The perturbation effect of the drugs depended largely on the lipid composition of the liposomes. The drugs at the drug/lipid molar ratios from 0.1 to 1 increased membrane dynamics and/or decreased membrane order. The drugs had the most pronounced perturbation effect in the liposomes prepared from brain total lipids. The effect of the drugs decreased with decreasing the TL/PC ratio in the liposomes and was lowest, almost diminished, in the PC liposomes. Increasing concentration of the drugs decreased the difference between the dynamics and/or order of the PC and TL liposomes and so eliminated the influence of lipid composition on these membrane parameters. The results emphasize the role of lipid composition in studies concerning drug-lipid interactions in model and biological membranes.