Inorganic phosphate stimulates the toxic effects of Tl+ in rat liver mitochondria

✍ Scribed by Sergey M. Korotkov; Larisa V. Emel'yanova; Olga V. Yagodina

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 272 KB
• Volume: 22
• Category: Article
• ISSN: 1095-6670
• DOI: 10.1002/jbt.20215

✦ Synopsis

We studied action of inorganic phosphate (P i ) on toxic effects of Tl + in isolated rat liver mitochondria. This is a convenient model to study the toxicity of heavy metals. P i markedly retarded contraction of energized mitochondria swollen in the TlNO 3 medium and even stronger stimulated swelling and state 4 of succinate-energized mitochondria in the TlNO 3 medium. A valinomycin-induced decrease of K + -diffusion potential was also accelerated by Tl + in the presence of P i . The mitochondrial permeability transition pore in the medium containing Ca 2+ , TlNO 3 , and nitrates of univalent cations was distinctly stimulated by P i . However, P i did not affect both the Tl +stimulated swelling of nonenergized mitochondria in the TlNO 3 medium and swelling of energized mitochondria in the Tl acetate medium. Respiration stimulated by 2,4-dinitrophenol and monoamine oxidase activity of energized mitochondria were not affected by Tl + regardless of the presence of P i . We suggested that stimulation by P i of toxic action of Tl + in mitochondria and cells could be due to even greater enhancement of uncoupling of mitochondria as shown by an additional increase of swelling and state 4, and in the greater probability of opening of MPTP in the presence of P i and Ca 2+ .