The effects of methylmercury on mitochondrial function and reactive oxygen species formation in rat striatal synaptosomes are age-dependent

Toxicol Sci. 2005 Sep;87(1):156-62. doi: 10.1093/toxsci/kfi224. Epub 2005 Jun 15.


Methylmercury (MeHg) is especially toxic to the developing central nervous system. In order to understand the reasons for this age-dependent vulnerability, we compared the effects of MeHg on formation of reactive oxygen species (ROS) and mitochondrial function in striatal synaptosomes obtained from rats of various ages. Basal ROS levels were greater, and basal mitochondrial function was lower, in synaptosomes from younger animals, compared to adult animals. MeHg induced ROS formation in synaptosomes from rats of all ages, although the increases were greatest in synaptosomes from the younger animals. MeHg also reduced mitochondrial metabolic function, as assessed by MTT reduction, as well as mitochondrial membrane potential; again, the greatest changes were seen in synaptosomes from early postnatal animals. These age-dependent differences in susceptibility to MeHg are most likely due to a less efficient ROS detoxifying system and lower activity of mitochondrial enzymes in tissue from young animals.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Age Factors
  • Animals
  • Corpus Striatum / drug effects*
  • Corpus Striatum / metabolism
  • Male
  • Membrane Potentials / drug effects
  • Methylmercury Compounds / toxicity*
  • Mitochondria / drug effects*
  • Mitochondria / physiology
  • Rats
  • Rats, Long-Evans
  • Reactive Oxygen Species / metabolism*
  • Synaptosomes / drug effects*
  • Synaptosomes / metabolism


  • Methylmercury Compounds
  • Reactive Oxygen Species