Angiotensin II and related peptides alter liposomal membrane fluidity.
We investigated the effects of angiotensinogen (Ang), angiotensin I (Ang I), and angiotensin II (Ang II) on the fluidity of phosphatidylcholine vesicles. Changes in fluidity were assessed by changes in anisotropy values calculated from fluorescence polarization measurements. All three compounds produced an increase in membrane fluidity when localized inside the phosphatidylcholine vesicles. When placed outside the vesicles, Ang II increased bilayer rigidity (decreased fluidity), whereas Ang and Ang I produced no effect. These results suggest the possibility that these peptides may alter the fluidity of cell membranes by a direct action on the phospholipid bilayer, which may in turn interfere with receptor-mediated effects.
Brailoiu
E
E
Department of Pharmacology, East Tennessee State University, James H. Quillen College of Medicine, Johnson City 37614, USA.
Margineanu
A
A
Miyamoto
M D
MD
D000804:Angiotensin II / Q000494:pharmacology*; D005454:Fluorescence Polarization; D008051:Lipid Bilayers / Q000378:metabolism; D008081:Liposomes / Q000378:metabolism*; D008560:Membrane Fluidity / Q000187:drug effects*; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology*
D008051:Lipid Bilayers; D008081:Liposomes; D010455:Peptides; D000804:Angiotensin II