Metabolism of carbidopa to alphamethyldopamine and alphamethylnorepinephrine in rats

Academic Article


  • Recent observations on the central and peripheral actions of carbidopa (CD) combined with our own results with the compound led us to examine its metabolism and effects on brain catecholamines in rats. CD was found to undergo a two-stage N-deamination process in vivo giving rise to alpha-methyldopa (AMD) and alpha-methyldopamine respectively. Further, beta-hydroxylation yielded alpha-methylnorepinephrine. These metabolic products were demonstrated in rat brain with reductions in norepinephrine and 3-methoxy-4-hydroxyphenylglycol, and little effect on dopamine. These results are consistent with the alpha-2 agonist effects of alpha-methylnorepinephrine. The relative formation of alpha-methyldopamine from CD was about 26% of an equivalent dose of AMD. It is concluded that some of the central effects of CD may be mediated by its metabolism to AMD. which readily crosses the blood-brain barrier. Possible implications of the findings are discussed. © 1985.
  • Authors

    Published In

    Digital Object Identifier (doi)

    Author List

  • Shelton RC; Karoum F; Chuang LW; Wyatt RJ
  • Start Page

  • 3623
  • End Page

  • 3626
  • Volume

  • 34
  • Issue

  • 20