title: Effect of PAF on polyrnorphonuclear leucocyte plasma membrane polarity: a fluorescence study.
abstract: The effect of PAF on the plasma membrane polarity of polymorphonuclear leukocytes (PMNs) was investigated by measuring the steady-state fluorescence emission spectra of 2-dimethylamino(6-1auroyl) naphthalene (Laurdan), which is known to be incorporated at the hydrophobic-hydrophilic interface of the bilayer, displaying spectral sensitivity to the polarity of its surrounding. Laurdan shows a marked steady-state emission blue-shift in non-polar solvents, with respect to polar solvents. Our results demonstrate that PAF (10(-7) M) induces a blue shift of the fluorescence emission spectra of Laurdan. These changes are blocked in the presence of the PAF antagonist, L-659,989. Our data indicate that the interaction between PAF and PMNs is accompanied by a decrease in polarity in the hydrophobic-hydrophilic interface of the plasma membrane.
authors.affiliation: Departments of Pediatrics University of Ancona via Corridoni 11 Ancona 60123 Italy.
authors.forename: A
authors.initials: A
authors.lastname: Kantar
authors.forename: P L
authors.initials: PL
authors.lastname: Giorgi
authors.forename: R
authors.initials: R
authors.lastname: Fiorini