Evaluation of estrogen neuroprotective effect on nigrostriatal dopaminergic neurons following 6-hydroxydopamine injection into the substantia nigra pars compacta or the medial forebrain bundle

Neurochem Res. 2008 Jul;33(7):1238-46. doi: 10.1007/s11064-007-9575-7. Epub 2008 Feb 9.


Studies involving estrogen treatment of ovariectomized rats or mice have attributed to this hormone a neuroprotective effect on the substantia nigra pars compacta (SNpc) neurons. We investigated the effect of estradiol replacement in ovariectomized rats on the survival of dopaminergic mesencephalic cell and the integrity of their projections to the striatum after microinjections of 1 microg of 6-hydroxydopamine (6-OHDA) into the right SNpc or medial forebrain bundle (MFB). Estradiol replacement did not prevent the reduction either in the striatal concentrations of DA and metabolites or in the number of nigrostriatal dopaminergic neurons following lesion with 1 microg of 6-OHDA into the SNpc. Nevertheless, estradiol treatment reduced the decrease in striatal DA following injection of 1 microg of 6-OHDA into the MFB. Results suggest therefore that estrogen protect nigrostriatal dopaminergic neurons against a 6-OHDA injury to the MFB but not the SNpc. This may be due to the distinct degree of lesions promoted in these different rat models of Parkinson's disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Survival / drug effects
  • Dopamine / metabolism
  • Dopamine / physiology*
  • Drug Implants
  • Estradiol / administration & dosage
  • Estradiol / pharmacology
  • Estrogens / pharmacology*
  • Female
  • Homovanillic Acid / metabolism
  • Medial Forebrain Bundle / metabolism
  • Medial Forebrain Bundle / physiology*
  • Microinjections
  • Neurons / drug effects*
  • Neuroprotective Agents*
  • Ovariectomy
  • Oxidopamine
  • Pregnancy
  • Rats
  • Substantia Nigra / cytology
  • Substantia Nigra / drug effects*
  • Substantia Nigra / metabolism
  • Sympathomimetics


  • Drug Implants
  • Estrogens
  • Neuroprotective Agents
  • Sympathomimetics
  • Estradiol
  • Oxidopamine
  • Dopamine
  • Homovanillic Acid