Effects of nitric oxide on mitochondrial permeability transition pore and thiol-mediated responses in cardiac myocytes.
Nitric oxide (NO) alters the opening of mitochondrial permeability transition pore (mPTP). However, the signaling pathways of NO on mPTP remain elusive. We aimed to clarify the contribution of thiol-mediated responses to the effects of NO on mPTP in permeabilized myocytes. We found that (1) a high concentration of spermine NONOate (an NO donor; 500 μM) opened mPTP and depolarized ΔΨ(m). (2) A low concentration of NONOate (5 μM) prevented atractyloside (an mPTP opener)-induced mPTP opening. (3) Mn(III) tetrakis (4-benzoic acid) porphyrin (Mn-TBAP, ONOO(-) scavenger) attenuated the effect of high-concentration NONOate on mPTP opening, but did not inhibited the preventive effects of low-concentration NONOate. (4) When the interaction of NO with thiol was inhibited by N-ethylmaleimide, the opening (by high-concentration NONOate) and preventive effects (by low-concentration NONOate) of NONOate on mPTP were blocked. (5) Dithiothreitol (an inhibitor of disulfide bonds formation) prevented high-concentration NONOate-induced mPTP opening. (6) Ascorbic acid (an inhibitor of S-nitrosylation) prevented the preventive effects of low-concentration NONOate on mPTP. We conclude that opening of mPTP by high-concentration NO is related to disulfide bonds formation and oxidizing effects of ONOO(-). In contrast, the inhibitory effect of physiological concentrations of NO on mPTP is related to S-nitrosylation.
Department of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Japan.
Hayato
H
Ohtani
Hideki
H
Katoh
Takamitsu
T
Tanaka
Masao
M
Saotome
Tsuyoshi
T
Urushida
Hiroshi
H
Satoh
Hideharu
H
Hayashi
D000818:Animals; D001278:Atractyloside / Q000494:pharmacology; D002478:Cells, Cultured; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D004220:Disulfides / Q000378:metabolism; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D033681:Mitochondrial Membrane Transport Proteins / Q000187:drug effects* / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism*
D004220:Disulfides; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D013438:Sulfhydryl Compounds; D001278:Atractyloside; D009569:Nitric Oxide; D003545:Cysteine