Uptake of methylmercury in the rat brain: effects of amino acids

M. Aschner, T. W. Clarkson

Research output: Contribution to journalArticle

104 Scopus citations

Abstract

Aspects of the regulation of methylmercury (MeHg) transport across the blood-brain barrier (BBB) were investigated in the in vivo Long-Evans female rat. Fifteen s after intracarotid injection, brain 203Hg concentration was significantly increased in animals injected with 0.05 mM [203Hg]MeHgCl plus 0.1 mM l-cysteine compared with controls (P < 0.05). This l-cysteine-enhanced 203Hg brain uptake was abolished by coinjections of [203Hg]MeHgCl with 0.1 mM l-cysteine-l-methionine, or 0.1 mM l-cysteine plus AT-125 (α S, 5S-α-amino-3-chloro-4,5-dihydro-5-isoxazolacetic acid), an irreversible inhibitor of γ-glutamyl transpeptidase. Coinjections of rats with [203Hg]MeHgCl and 0.1 mM d-cysteine did not result in an increase in the rate of 203Hg uptake compared with controls. Furthermore, [203Hg]MeHg uptake at 15 s after intracarotid injections in the rat was stereospecific to the neutral amino acid carrier, as 203Hg uptake across the BBB was not inhibited by coinjections of [203Hg]MeHgCl with aspartic acid, an acidic amino acid. These results indicate the presence in brain capillaries of a transport system capable of selectively mediating MeHg uptake across the brain capillary endothelial cell membrane.

Original languageEnglish (US)
Pages (from-to)31-39
Number of pages9
JournalBrain research
Volume462
Issue number1
DOIs
StatePublished - Oct 11 1988
Externally publishedYes

Keywords

  • Blood-brain barrier
  • Methylmercury
  • Rat
  • Transport
  • l-Cysteine

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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