Uraemia suppresses central dopaminergic metabolism and impairs motor activity in rats

Objective: Uraemia often provokes various neurological disorders, such as mental changes, malperception, confusion, seizures and coma. Since changes in neurotransmissions induce neurological symptoms, we investigated changes in the monoamine metabolism and motor activity in uraemic rats. Design: Prospective, randomised, controlled animal study. Subjects: Male Wistar rats. Interventions: Acute renal failure was induced by occlusion of bilateral renal arteries for 60 min, and the motor activity and brain monoamine turnover were examined 48 h later. The brain monoamine turnover was evaluated by the depletion of norepinephrine (NE) and dopamine (DA) induced by a-methyl-p-tyrosine (a-MT), or the accumulation of 5-hydroxyindoleacetic acid (5-HIAA) induced by probenecid. Measurements and results: Marked damage in renal function was found in animals subjected to renal ischaemia 48 h after the operation. The motor activity of the uraemic rats was impaired. The turnover of DA in the striatum, mesencephalon and hypothalamus was decreased in these rats. The turnover of NE and 5-hydroxytryptamine (5-HT) was unchanged in all regions examined. Conclusions: Suppression of the central DA turnover appears to be involved in the impairment of motor activity in uraemic rats.