Abstract
Effects of the psychotropic model drug desipramirie (DMI) on apparent membrane fluidity were measured in suspensions of cultured human fibroblasts in Hank's balanced salt solution by a fluorescence polarization technique using anthroyloxystearic acids (AS) as probes. Cells were incubated with 1 uM 6 or 12-AS in prescence or absence of 5 uM DMI at temperatures variing between 37° and 4°C. Fluidity increased with the depth of the probes in the membrane (12 AS > 6 AS) and with increasing temperature. Measured anisotropy r(G), inversely correlated to fluidity, at 37°C in drug treated cells (±SD) was 0.073±0.007 for 12 AS (controls: 0.096±0.012) and 0.124±0.006 for 6 AS (0.130±0.014). At 25°C r(G) was 0.112±0.012 for 12 AS (0.118±0.014) and 0.188±0.011 for 6 AS (0.178±0.008). This suggests that the drug is fluidizing the deeper, hydrophobic layer of the membrane at 37°C, but not at 25°C. Measurements of membrane fluidity in various depth of the membranes may be helpful to study effects of lipid soluble drugs.
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Toplak, H., Hermetter, A., Honegger, U. et al. MEMBRANE FLUIDITY: A NEW BIOPHYSICAL METHOD FOR STUDIES OF DRUG EFFECTS IN HUMAN FIBROBLASTS. Pediatr Res 22, 217 (1987). https://doi.org/10.1203/00006450-198708000-00023
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DOI: https://doi.org/10.1203/00006450-198708000-00023