Voltametric measurement of blood nitric oxide in irradiated rats

Purpose: To investigate the effect of blood nitric oxide (NO) as a mediator of the neurovascular syndrome in rats following gamma-irradiation. Material and methods: Using a voltametric method together. with a carbon fi bre based sensor, NO measurements were carried out in sham-irradiated and i rradiated animals either in blood from the: abdominal aorta or in blood sam ples from the heart. Results: In in vitro conditions, properties of the probe were not altered b y the ionizing radiation. Significant increases of +17% and + 25.6% were ob served in the voltametric signal height at 90 min and 24 h respectively aft er a 15 Gy gamma-ray exposure. These effects were followed on days 3 and 4 by a progressive decrease in the signal height of 7% and 18% respectively. Dose-effect relationships were observed at 90 min and 24-h after exposure t o gamma-rays in the. range of 3-15 Gy. Finally, the NO dependence on the me asured voltametric signal was controlled by using inhibitors of the NO synt hase (NOS) and by performing nitrate assays. Conclusions: Specific blood NO voltametric measurements are possible. Funct ional changes associated with NO after gamma-ray exposure are discussed.