Acute sodium-dependent changes in membrane dynamic properties.
Na+ ions, which can play a pathogenic role in the development of high blood pressure, have been reported to regulate membrane enzymatic activities, receptor-ligand interaction and coupling of G-protein receptors to their effectors. This study was designed to investigate the in vitro effects of Na+ ions on membrane dynamic properties. The fluorescence anisotropy values of TMA-DPH (trimethylamino-diphenylhexatriene, probe selectively incorporated into the outer leaflet of the plasma membrane) was evaluated in platelets and erythrocytes of sodium-dependent hypertension-prone and -resistant rats of the Sabra Strain. Whereas no difference was observed between the 2 strains, TMA-DPH anisotropy was found to be strongly influenced in platelets by external Na+ ions. In the absence of external Na+, TMA-DPH anisotropy increased in human and rat platelets. In contrast, Na+ ions did not affect the anisotropy when the probe was inserted into erythrocyte ghosts. This indicates that Na+ ions can acutely regulate order parameter and microviscosity of platelet plasma membrane in the regions explored by the probe.
Le Quan Sang
K H
KH
Pharmacology, Necker Medical School, CNRS 6167, Paris, France.
Mazeaud
M
M
Pernollet
M G
MG
Ben Ishay
D
D
Devynck
M A
MA
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004161:Diphenylhexatriene / Q000031:analogs & derivatives / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005454:Fluorescence Polarization; D008297:Male; D008560:Membrane Fluidity / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism* / Q000494:pharmacology; D014783:Viscosity
D004161:Diphenylhexatriene; C033628:1-(4-(trimethylamino)phenyl)-6-phenylhexa-1,3,5-triene; D012964:Sodium