The adrenergic innervation of major arteries and veins was examined in Dahl salt-sensitive (DS) and salt-resistant (DR) rats using a histochemical fluorescent technique to detect the intraneuronal catecholamine content. Under the conditions of low salt intake the density of adrenergic plexus tended to be higher in DR than in DS rats. A decrease of catecholamine content with a subsequent reduction in the density of visible adrenergic plexus was observed in mesenteric and renal but not in femoral vascular beds of salt hypertensive DS rats. The adrenergic innervation was more altered in veins than in respective arteries. Pronounced alterations of vascular sympathetic innervation induced by high salt intake in DS rats contrasted with negligible changes occurring in DR animals. Observed changes of adrenergic innervation in particular vascular beds of salt hypertensive DS rats could reflect the enhanced catecholamine turnover and sympathetic hyperactivity which is important for the pathogenesis and/or maintenance of salt hypertension in Dahl salt-sensitive rats.