Document Detail

Anacardic acid-mediated changes in membrane potential and pH gradient across liposomal membranes.
MedLine Citation:
PMID:  11750264     Owner:  NLM     Status:  MEDLINE    
We have previously shown that anacardic acid has an uncoupling effect on oxidative phosphorylation in rat liver mitochondria using succinate as a substrate (Life Sci. 66 (2000) 229-234). In the present study, for clarification of the physicochemical characteristics of anacardic acid, we used a cyanine dye (DiS-C3(5)) and 9-aminoacridine (9-AA) to determine changes of membrane potential (DeltaPsi) and pH difference (DeltapH), respectively, in a liposome suspension in response to the addition of anacardic acid to the suspension. The anacardic acid quenched DiS-C3(5) fluorescence at concentrations higher than 300 nM, with the degree of quenching being dependent on the log concentration of the acid. Furthermore, the K(+) diffusion potential generated by the addition of valinomycin to the suspension decreased for each increase in anacardic acid concentration used over 300 nM, but the sum of the anacardic acid- and valinomycin-mediated quenching was additively increasing. This indicates that the anacardic acid-mediated quenching was not due simply to increments in the K(+) permeability of the membrane. Addition of anacardic acid in the micromolar range to the liposomes with DeltaPsi formed by valinomycin-K(+) did not significantly alter 9-AA fluorescence, but unexpectedly dissipated DeltaPsi. The DeltaPsi preformed by valinomycin-K(+) decreased gradually following the addition of increasing concentrations of anacardic acid. The DeltaPsi dissipation rate was dependent on the pre-existing magnitude of DeltaPsi, and was correlated with the logarithmic concentration of anacardic acid. Furthermore, the initial rate of DeltapH dissipation increased with logarithmic increases in anacardic acid concentration. These results provide the evidence for a unique function of anacardic acid, dissimilar to carbonylcyanide p-trifluoromethoxyphenylhydrazone or valinomycin, in that anacardic acid behaves as both an electrogenic (negative) charge carrier driven by DeltaPsi, and a 'proton carrier' that dissipates the transmembrane proton gradient formed.
Masaaki Toyomizu; Katsuyuki Okamoto; Yukio Akiba; Tetsuo Nakatsu; Tetsuya Konishi
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  1558     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  2002 Jan 
Date Detail:
Created Date:  2001-12-25     Completed Date:  2002-02-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  54-62     Citation Subset:  IM    
Science of Biological Function, Life Science, Graduate School of Agriculture, Tohoku University, Sendai, Japan.
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MeSH Terms
Anacardic Acids*
Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / chemistry
Dose-Response Relationship, Drug
Fluorescent Dyes
Gramicidin / chemistry
Hydrogen-Ion Concentration / drug effects
Liposomes / chemistry*
Membrane Potentials / drug effects
Models, Chemical
Molecular Structure
Salicylic Acids / chemistry,  pharmacology*
Spectrometry, Fluorescence / methods
Valinomycin / chemistry
Reg. No./Substance:
0/Anacardic Acids; 0/Benzothiazoles; 0/Carbocyanines; 0/Fluorescent Dyes; 0/Liposomes; 0/Salicylic Acids; 1405-97-6/Gramicidin; 18654-18-7/anacardic acid; 2001-95-8/Valinomycin; 370-86-5/Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; 53213-94-8/3,3'-dipropyl-2,2'-thiadicarbocyanine; 90-45-9/Aminacrine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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