Cholesterol-dependent gramicidin A channel inactivation in red blood cell membranes and lipid bilayer membranes.
The exchange diffusions of tracer cations (22Na+, 86Rb+) are studied on gramicidin-A-treated red blood cell (RBC) membranes. A time-dependent decrease in cation permeability has been observed and has been considered to be the result of a channel inactivation process. The channel inactivation appears at 20 and 30 degrees C but not at a temperature as low as 6 degrees C. The gramicidin A channel inactivation can be monitored by a conductivity decay of molecular lipid membranes (BLM) prepared either from cholesterol or from a mixture of cholesterol and phospholipids but not of pure phosphatidylethanolamine. The role of cholesterol in the channel inactivation is discussed.
Schagina
L V
LV
Institute of Cytology, Academy of Sciences U.S.S.R., Leningrad.
Blaskó
K
K
Grinfeldt
A E
AE
Korchev
Y E
YE
Lev
A A
AA
D002412:Cations; D002463:Cell Membrane Permeability; D002784:Cholesterol / Q000494:pharmacology* / Q000502:physiology; D004058:Diffusion; D004553:Electric Conductivity; D004910:Erythrocyte Membrane / Q000378:metabolism*; D006096:Gramicidin / Q000494:pharmacology*; D006801:Humans; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008051:Lipid Bilayers / Q000378:metabolism*; D012414:Rubidium Radioisotopes; D012979:Sodium Radioisotopes; D013696:Temperature
D002412:Cations; D007473:Ion Channels; D008051:Lipid Bilayers; D012414:Rubidium Radioisotopes; D012979:Sodium Radioisotopes; D006096:Gramicidin; D002784:Cholesterol