Passive smoking impairs endothelium-dependent relaxation of isolated rabbit arteries

The aim of the present study was to examine the effect of prolonged passive smoking (lasting 3 weeks) on plasma catecholamine levels and reactivity of isolated rabbit arteries. Plasma noradrenaline, adrenaline and dopamine le vels were determined radioenzymatically. Isolated rings of the thoracic aor ta and carotid artery were suspended in organ chambers and connected to a f orce transducer for the recording of isometric tension. Plasma noradrenalin e levels were found to be significantly elevated in rabbits subjected to pa ssive smoking for 3 weeks. Plasma adrenaline and dopamine levels were not c hanged. Transmural nerve stimulation of arterial rings evoked frequency-dep endent contractions. Prolonged passive smoking did not affect neurogenic co ntractions of the arteries tested. On the other hand, endothelium-dependent relaxations of phenylephrine-precontracted arteries were significantly imp aired. Furthermore, hypertrophy of the left ventricle was observed. In conc lusion, passive smoking impairs endothelium-dependent relaxations but not n eurogenic contractions of systemic arteries. The impaired relaxations of ar teries may be, at least in part, mediated through the degradation of releas ed nitric oxide by superoxide anions derived from cigarette smoke.