Excitatory and Inhibitory Actions of Isoprostanes in Human and Canine Airway Smooth Muscle 1 1 This study was supported by an operating grant and a Scientist Award from the Medical Research Council of Canada (to L.J.J.).

Isoprostanes are generated nonenzymatically during free radical-mediated lipid peroxidation, and are used clinically and experimentally as markers of oxidative stress. However, their biological effects are poorly understood. We examined the effects of seven different 8-isoprostanes in human and canine airway smooth muscles. In large order airways (carina) of the human, several isoprostanes evoked powerful contractions, with 8-iso-prostaglandin …