title: Change of membrane fluidity of rat neutrophils accompanying Escherichia coli inoculation.
abstract: Membrane fluidity of rat neutrophils was studied following Escherichia coli inoculation, and characteristic changes were observed. Membrane fluidity was assessed by the excimer-forming lipid technique using pyrenedecanoic acid and flow cytometry and expressed as the fluorescence intensity ratios of excimer and monomer pyrenedecanoic acid (IE/IM ratio). High IE/IM ratios indicated high membrane fluidity. The IE/IM ratio of rat neutrophils (0.50 +/- 0.048) increased after E. coli inoculation, reaching a maximum of almost 1.00 after 10-20 min and then returning to its starting value. Intravenous injection of heat-killed E. coli or E. coli-conditioned culture supernatants into rats induced a rapid increase of IE/IM ratios, which returned to initial levels after 20 min. The effect on membrane fluidity of in vitro neutrophil incubation with E. coli, heat-killed E. coli, or E. coli-conditioned culture supernatants was similar to that observed in vivo. Addition of 5 mM ethylenediaminetetraacetic acid (EDTA) did not affect neutrophil membrane fluidity. Addition of either 5 micrograms/ml cytochalasin B or 10(-5) M colchicine did not directly affect neutrophil membrane fluidity but did block the change observed following incubation with bacteria.
authors.affiliation: Department of Clinico-laboratory Medicine, Kansai Medical University, Osaka, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Masuda
authors.forename: Y
authors.initials: Y
authors.lastname: Komiyama
authors.forename: H
authors.initials: H
authors.lastname: Nishikado
authors.forename: H
authors.initials: H
authors.lastname: Kuriki
authors.forename: H
authors.initials: H
authors.lastname: Egawa
authors.forename: K
authors.initials: K
authors.lastname: Murata
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D003078:Colchicine / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004926:Escherichia coli; D007275:Injections, Intravenous; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects; D008870:Microtubules / Q000187:drug effects; D009504:Neutrophils / Q000382:microbiology / Q000502:physiology / Q000648:ultrastructure*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D003571:Cytochalasin B; D004492:Edetic Acid; D003078:Colchicine