Affordable Access

Publisher Website

Further studies on the sequence of dopamine metabolism in the rat brain

European Journal of Pharmacology
Publication Date
DOI: 10.1016/0014-2999(79)90261-9
  • Homovanillic Acid Turnover
  • 3
  • 4-Dihydroxyphenylacetic Acid
  • 3-Methoxytyramine
  • Pargyline Dopamine Metabolism
  • Tropolone


Abstract The time—response curve of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) concentrations in the striatum of the rat were measured during apomorphine, haloperidol, morphine, oxotremorine or reserpine treatment as well as after a brain lesion. The results showed that changes in DOPAC concentrations consistently preceded changes in HVA concentrations. It was concluded that HVA must be considered as a “second metabolite” rather than as a marker of extra-neuronal metabolism. The turnover of HVA calculated after tropolone treatment revealed that this compound can be considered as a reliable COMT inhibitor. The turnover of 3-methoxytyramine (3-MT) calculated after tropolone treatment (during MAO inhibition) appeared to be 1.9 nmol/g/h. From this relatively low value it was concluded that 3-MT cannot be considered as an alternative metabolite for DA degradation during MAO inhibition. 3-MT concentrations measured after apomorphine or γ-hydroxybutyric acid treatment also suggest that 3-MT leaves the brain to only a minor extent during MAO inhibition. The effects of reserpine on pargyline-induced 3-MT concentrations indicate that there is hardly any COMT-activity in dopaminergic terminals. Evidence was provided that, at least during reserpine or pargyline treatment, dopamine leaves the brain unmetabolized or via unknown metabolic pathways.

There are no comments yet on this publication. Be the first to share your thoughts.


Seen <100 times

More articles like this

Further studies on the sequence of dopamine metabo...

on European Journal of Pharmacolo... Jul 01, 1979

Sequence and significance of dopamine metabolism i...

on Neurochemistry International Jan 01, 1985

Sequence and significance of dopamine metabolism i...

on Neurochemistry International 1985

Effects of the l isomer of fenfluramine on dopamin...

on European Journal of Pharmacolo... Jan 01, 1989
More articles like this..