Elevation in arterial blood pressure following the development of tachyphylaxis to peroxynitrite.

The systemic administration of peroxynitrite produces transient reductions in mean arterial pressure and vascular resistances in anesthetized rats. The repeated administration of peroxynitrite results in tachyphylaxis. We now report that anesthetized rats (n = 8) treated with peroxynitrite (10 injections of 10 mumol/kg i.v.) subsequently develop increases in mean arterial pressure (20 +/- 4%) and hindquarter (153 +/- 28%), renal (93 +/- 21%), and mesenteric (133 +/- 25%) vascular resistances. These findings suggest that the in vivo production of peroxynitrite may contribute to the pathogenesis of hypertension.