Comparison of responses to novel nitric oxide donors in the feline pulmonary vascular bed

Pulmonary vascular responses to the novel diazeniumdiolate nitric oxide (NO ) donors diethylamine/NO, diethylenetriamine/NO, spermine/NO, sulfite/NO, a nd angeli's salt, were investigated and compared in the intact-chest cat. U nder conditions of controlled blood flow, when tone in the pulmonary vascul ar bed had been raised to a high steady level, intralobar injections of die thylamine/NO (0.3-10 mug), diethylenetriamine/NO (10-30 mug), spermine/NO ( 10-30 mug), sulfite/NO (10-30 mug), and angeli's salt (10-30 mug) caused do se-related decreases in lobar arterial pressure without changing left atria l pressure. In terms of relative vasodilator activity in the pulmonary vasc ular bed, the dose of the compounds that decreased lobar arterial pressure 4 mm Hg (ED4 mm Hg) was significantly lower for diethylamine/NO compared to S-nitroso-N-acetylpenicillamine which was significantly less than diethyle netriamine/NO, spermine/NO, sulfite/NO, and angeli's salt. The half-life of the vasodilator responses, as measured by 50% response recovery time, to d iethylamine/NO, diethylenetriamine/NO, spermine/NO, sulfite/NO, and angeli' s salt was similar for doses with similar magnitudes of vasodilation, while the half-life to S-nitroso-N-acetylpenicillamine was significantly less th an the diazeniumdiolate NO donors. The present data demonstrate that the di azeniumdiolate NO donors diethylamine/NO, diethylenetriamine/NO, spermine/N O, sulfite/NO, and angeli's salt have potent but relatively short-lasting v asodilator activity in the pulmonary vascular bed of the cat. (C) 2001 Publ ished by Elsevier Science B.V.