n-Amyl alcohol partitioning in synaptic plasma membranes.
Nuclear magnetic resonance and fluorescence polarization techniques were used to determine n-amyl alcohol partitioning between, and effects on, lipid microdomains of isolated rat cerebral synaptic plasma membranes. n-Amyl alcohol binding to the hydrophobic membrane core had an unchanging binding constant over an aqueous alcohol concentration range of 2.5-22.5 mM, indicating a linear relationship between membrane core and aqueous alcohol concentrations. Binding to the membrane surface, in contrast, was cooperative with a steadily increasing binding constant over this alcohol concentration range. Membrane lipid order was determined using various fluorescent probes with preferences for the membrane core, for the mid-acyl regions of the exofacial or cytofacial bilayer leaflets and for ordered or bulk microdomains. All these probes showed steady decreases in membrane order with increasing alcohol concentration, at least for the nanosecond time scale sampled by this technique. These results further demonstrate the complexity of interaction between natural membranes and membrane disordering agents.
Mrak
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RE
Pathology and Laboratory Medicine Service, John L. McClellan Memorial Veterans' Hospital, Little Rock, AR 72205.
Fowler
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A
Komoroski
R A
RA
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D005454:Fluorescence Polarization; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D000439:Pentanols / Q000378:metabolism / Q000493:pharmacokinetics* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure
D000439:Pentanols