Yonsei Med J.  1995 Jun;36(3):299-305. 10.3349/ymj.1995.36.3.299.

Selective inhibition of glutamate uptake by mercury in cultured mouse astrocytes

• Kim P
• Choi BH

• KMID: 1123185
• DOI: http://doi.org/10.3349/ymj.1995.36.3.299

Abstract

We studied the effects of organic and inorganic mercury (Hg) on the uptake of L-[3H] glutamate (L-GLU) in cultured mouse astrocytes. Following exposure to mercuric chloride (MC) [0.2 approximately 5.0 microM], selective and dose-dependent inhibition of L-GLU uptake to 50% of control levels was observed, whereas 2-deoxyglucose (2-DG) uptake was not significantly affected. Methylmercuric chloride (MMC) also inhibited L-GLU uptake but 50% reduction was reached only at a concentration of 10 microM. Inhibition of L-GLU uptake by MMC appears to be closely linked to voltage-sensitive calcium channels as evidenced by the lack of L-GLU uptake inhibition by MMC in calcium-free medium or in the presence of the channel blocker verapamil. Exposure to a variety of divalent metallic ions, including CuCl2, FeCl2 and ZnCl2, did not affect L-GLU uptake in astrocytes in vitro. Exposure to PbCl2, however, resulted in a decline in L-GLU uptake, though to a much smaller degree than that observed with Hg compounds. Selective impairment of astroglial L-GLU transport may represent a critical early pathogenetic feature of Hg-induced neurotoxicity.

Keyword

Glutamate uptake; mercury; astrocytes; cultures

MeSH Terms

Animal
Astrocytes/*drug effects/metabolism
Cells, Cultured
Glutamic Acid/*metabolism
Mercury/*toxicity
Mice
Mice, Inbred C57BL
Support, U.S. Gov't, P.H.S.