title: DiO-C3-(5) and DiS-C3-(5): Interactions with RBC, ghosts and phospholipid vesicles.
abstract: The experiments presented below compare the interaction of diO-C3-(5) and diS-C3-(5) with erythrocytes, erythrocyte ghosts and phospholipid vesicles derived from erythrocyte membranes. The results confirm earlier reports of diS-C3-(5) dimerization in the presence of hemoglobin and of dye aggregate formation in erythrocyte suspensions. DiO-C3-(5), on the other hand, binds to vesicles and ghosts freed of hemoglobin in a potential-dependent manner but without forming dye aggregates. The two dyes bind to the different preparations in similar proportions, but diS-C3-(5) is bound in amounts 3-40 times greater depending on the degree of polarization. The results show that mechanism other than binding to hemoglobin must occur in order to explain the potential-dependent binding of both dyes to ghosts and vesicles. A primary interaction must exist between the dye molecule and the lipid bilayer in a biological membrane, and this would be expected to occur in the presence of hemoglobin or other cytosolic components. DiO-C3-(5) is a better dye to use than diS-C3-(5) for mechanistic studies, in order to avoid problems associated with formation of complex aggregates of the latter dye, especially in hyperpolarized membrane suspensions.
mesh_terms: D052160:Benzothiazoles; D002232:Carbocyanines / Q000378:metabolism*; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D005453:Fluorescence; D005456:Fluorescent Dyes; D006801:Humans; D008051:Lipid Bilayers / Q000378:metabolism*; D008564:Membrane Potentials; D011188:Potassium / Q000378:metabolism; D011804:Quinolines / Q000378:metabolism*; D013053:Spectrophotometry
chemical_list: D052160:Benzothiazoles; D002232:Carbocyanines; D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D011804:Quinolines; C015843:3,3'-dipropyloxadicarbocyanine; C012944:3,3'-dipropyl-2,2'-thiadicarbocyanine; D011188:Potassium