title: Mitochondrial membrane potential in lymphocytes as monitored by fluorescent cation diS-C3-(5).
abstract: A lipophilic fluorescent cation diS-C3-(5) and rotenone suppress the oxygen consumption rate of thymocytes in similar concentrations. Seventy percent inhibition corresponds to an inhibitor:cytochrome a molar ratio of about 1:1. Addition of uncouplers decreases the inhibition of respiration by diS-C3-(5) (but not rotenone). FCCP in similar concentrations increases O2 consumption in the absence of diS-C3-(5) and the diS-C3-(5) fluorescence intensity in the presence of TMPD in thymocyte suspensions. In most thymocyte preparations, oligomycin (0.05-0.1 microgram/mL) increases the fluorescence of diS-C3-(5) and further addition of TMPD (50-100 microM) decreases the fluorescence. Addition of NaCN (400 microM) after oligomycin leads to a fluorescence increase that is hardly affected by subsequent addition of 0.2 microM FCCP. Nigericin (10-50 nM) decreases the diS-C3-(5) fluorescence. The data indicate that the diS-C3-(5) fluorescence associated with mitochondrial transmembrane potential (delta psi m) may be an essential part of the diS-C3-(5) fluorescence in lymphocyte suspensions. The changes of the diS-C3-(5) fluorescence intensity in the presence of TMPD after FCCP addition reflect delta psi m.
mesh_terms: D000818:Animals; D052160:Benzothiazoles; D002232:Carbocyanines / Q000494:pharmacology*; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D005029:Ethylenediamines / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000494:pharmacology*; D008214:Lymphocytes / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects*; D008928:Mitochondria / Q000378:metabolism*; D009840:Oligomycins / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D011804:Quinolines / Q000494:pharmacology*; D051381:Rats; D012402:Rotenone / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D013950:Thymus Gland / Q000166:cytology
chemical_list: D052160:Benzothiazoles; D002232:Carbocyanines; D005029:Ethylenediamines; D005456:Fluorescent Dyes; D009840:Oligomycins; D011804:Quinolines; D012402:Rotenone; C005798:N,N,N',N'-tetramethylethylenediamine; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; C012944:3,3'-dipropyl-2,2'-thiadicarbocyanine