Disease relevance of methyl-triphenyl-phosphanium

• Colicin K causes a rapid and drastic reduction of the membrane potential of Escherichia coli cells, as measured by the uptake of the lipophilic cation triphenylmethylphosphonium [1].
• Despite having lower cell membrane potentials, four human melanoma cell lines and HeLa cells accumulated the membrane probe triphenylmethylphosphonium ion (TPMP, 2 microM) 2-10 fold more rapidly than human fibroblasts, and did not reach equilibrium during the 2 h incubation period studied [2].

High impact information on methyl-triphenyl-phosphanium

• The SCN- and TPMP-measured Em of normal erythrocytes are -6.5 +/- 3 mV and -10 +/- 4 mV, respectively [3].
• With this in vitro experimental system, it has been demonstrated that a highly purified multidrug resistance protein functions as a drug pump, which transports methyltriphenylphosphonium actively against a 10(3)-fold concentration gradient [4].
• The mitochondrial membrane potential in isolated hepatocytes was measured using the distribution of the lipophilic cation triphenylmethylphosphonium (TPMP+) with appropriate corrections for plasma membrane potential, cytoplasmic and mitochondrial binding of TPMP+, and other factors [5].
• To modulate membrane potential, inhibitors of oxidative phosphorylation were used singly or in combination; their effect was monitored by following uptake of the nonmetabolizable lipophilic cation triphenylmethylphosphonium [6].
• Evidence that thyrotropin-releasing hormone transiently decreases membrane potential in mouse pituitary thyrotropic tumor cells in culture as monitored by triphenylmethylphosphonium ion [7].

Chemical compound and disease context of methyl-triphenyl-phosphanium

• Addition of valinomycin to tris(hydroxymethyl)aminomethane-ethylenediaminetetraacetic acid-treated E. coli cells in the presence of 20 mM exogenous potassium reduced the membrane potential, as measured by the uptake of the lipophilic cation triphenylmethylphosphonium, and caused a complete inhibition of glutamine transport [8].
• Some lipopolysaccharide-defective mutants of Escherichia coli showed, without ethylenediaminetetraacetic acid treatment, a quick and high uptake of lipophilic cations such as triphenylmethylphosphonium and tetraphenylphosphonium [9].

Biological context of methyl-triphenyl-phosphanium

• The dye fluorescence was found to be an indicator of membrane potential by correlation with triphenylmethylphosphonium ion distribution and with changes due to anaerobicity and ionophore addition [10].
• We conclude that unique relationships exist between delta mu H+ and the rates of oxidation and phosphorylation, and that under some conditions the behaviour of the probe TPMP+ is anomalous [11].

Anatomical context of methyl-triphenyl-phosphanium

• The predominantly mitochondrial localization of TPMP+ was confirmed using disruption procedures that selectively break the plasma membrane but not the mitochondrial membrane [12].
• Mitochondrial and plasma membrane potentials of 161 and 32.8 mV (negative inside), respectively, were calculated from the intracellular accumulation of triphenylmethylphosphonium (TPMP+) and thiocyanate in the intact hepatocyte, assuming a two-compartment model [12].
• Measurement of membrane potential of chromaffin granules by the accumulation of triphenylmethylphosphonium cation [13].
• Triphenylmethylphosphonium uptake by pancreatic islet cells [14].
• A method is described, based on the differential accumulation of Rb+ and methyltriphenylphosphonium, for the simultaneous estimation of the membrane potentials across the plasma membrane of isolated nerve endings (synaptosomes), and across the inner membrane of mitochondria within the synaptosomal cytoplasm [15].

Associations of methyl-triphenyl-phosphanium with other chemical compounds

• The membrane potential of normal splenocytes when measured with triphenylmethylphosphonium at 37 degrees was depolarized by 35% with 1 mM ouabain and thermally induced depolarization was blocked [16].
• Valinomycin, gramicidin, and triphenylmethylphosphonium ion all abolished the fluorescence changes [17].
• 1. We have monitored the plasma-membrane potential of lymphocytes by measuring the accumulation of the lipophilic cation methyltriphenylphosphonium (TPMP+) in the presence of the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) [18].
• In this study a lipophilic cation, triphenylmethylphosphonium (TPMP), was labelled with carbon-11 with the purpose of investigating its suitability for the estimation of membrane potential in vivo [19].
• Estimation of the membrane potential by the distribution of triphenylmethylphosphonium ion showed a modest effect of valinomycin (1-20 microM) in increasing the potential from -19 to -31 mV accompanied by an increase in serotonin uptake [20].

Gene context of methyl-triphenyl-phosphanium

• Triphenylmethylphosphonium cation distribution as a measure of hormone-induced alterations in white adipocyte membrane potential [21].
• Estimation of the relative change in the steady-state membrane potential of the murine keratinocyte cell line PAM 212, the murine myelomonocytic cell line P388D1, and normal human keratinocytes in culture, were made through the use of the lipophilic cationic membrane potential sensitive probe; triphenylmethylphosphonium [22].

Analytical, diagnostic and therapeutic context of methyl-triphenyl-phosphanium

• The mitochondrial membrane potential was assessed by an ion sensitive electrode to measure the distribution of methyltriphenylphosphonium across the inner mitochondrial membrane [23].
• Transmembrane potential (delta psi) was calculated from the distribution of triphenylmethylphosphonium between the mitochondrial, cytosolic, and extracellular compartments, which were separated by digitonin fractionation and centrifugation [24].
• The lipophilic cation triphenylmethylphosphonium appeared to distribute in a Nernstian fashion in the epithelial cells of Necturus gallbladder as judged by parallel microelectrode measurements [25].

References