Effects of inorganic and organic mercury on intracellular calcium levels in rat t lymphocytes

Xiaoxia Tan, Cuye Tang, Anna F. Castoldi, Luigi Manzo, Lucio G. Costa

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Abstract

The importance of cytosolic free calcium level (fCa2+]i) in lymphocyte activation prompted us to investigate changes in [Ca2+]i in T cells caused by mercury com-pounds, which have been shown to have immunomodulatory and immunotoxic properties. Using fura-2 as fluorescent Ca2+ indicator, we found that both methyl- mercury (MeHg; 0.02-2 nM) and inorganic mercury (HgCI2; 0.01-1 pM) increased [Ca2+]i in lymphocytes from rat spleen in a concentration-dependent manner. The effect of MeHg was rapid and the increase of Ca2+ level was sustained in time, while HgCI2 caused a slow rise in [Ca2+]i. The effects of mercury compounds did not appear to be associated with alterations of membrane integrity, since there was no significant difference in the extent of MnCI2 quench between control and mercury-treated cells. However, HgCI2 (1 jtM) and MeHg (2 nM) appeared to cause membrane damage at longer incubation times (15 min). When cells were incubated in Ca2+-free medium (in the presence of 1 mM EDTA) MeHg still increased [Ca2+]i, though to a lesser extent, while HgCI2 had no effect. Heparin, an inhibitor of inositol 1, 4, 5,-trisphosphate-induced Ca2+ mobilization partially blocked this rise of [Ca2+]i, white carbonyl cyanide m-chlorophenylhydraxone (CCCP),.

Original languageEnglish
Pages (from-to)159-170
Number of pages12
JournalJournal of Toxicology and Environmental Health
Volume38
Issue number2
DOIs
Publication statusPublished - 1993

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ASJC Scopus subject areas

  • Toxicology
  • Pollution

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