EFFECT OF TEMPERATURE ON POLARITY OF ANNULAR AND BILAYER LIPID IN SYNAPTIC-MEMBRANES

Using fluorescent probe pyrene a study was carried out of temperature dependence of the annular and lipid bilayer polarity in synaptic membranes. Polarity of microenvironment was evaluated by a ratio of intensities of vibronic bands in pyrene fluorescence spectra at direct excitation of probe or through energy transfer from protein molecules. At the temperature range 10-50-degrees-C the polarity of bilayer was shown to increase while that of annular lipid underwent biphasic changes. Above 20-degrees-C polarity of the bilayer was higher than of the annular zone. From experiments on pyrene fluorescence quenching with potassium iodide the conclusion has been made that changes in polarity correlate with pyrene accessibility to water.