Release of NO by a nitrosyl complex upon activation by the mitochondrial reducing power

The reaction of trans-[Ru(NH3)(4)P(OEt)(3)NO](3+) and mitochondria was investigated through differential pulse polarography and fluorimetry. The nitrosyl complex undergoes one-electron reduction centered on the NO ligand site. The reaction between the mitochondrial reductor and trans- [Ru(NH3)(4)P(OEt)(3) NO](2+) exhibits a second order specific rate constant calculated as k=2x10(1) M-1 s(-1). The reduced species, trans- [Ru(NH3)(4)P(OEt)(3) NO](2+), quickly releases NO, yielding trans-[Ru(NH3)(4)P(OEt)(3)H2O](2+). The low toxicities of both trans- [Ru(NH3)(4)P(OEt)(3) (NO)](2+) and trans- [Ru(NH3)(4)P(OEt)(3)H2O](2+) and its ability to release NO after reductive activation in a biological medium make the nitrosyl compound a useful model of a hypotensive drug. (C) 2002 Elsevier Science Inc. All rights reserved.