title: Evaluation of estrogen neuroprotective effect on nigrostriatal dopaminergic neurons following 6-hydroxydopamine injection into the substantia nigra pars compacta or the medial forebrain bundle.
abstract: 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.
authors.affiliation: Laboratório de Neurofisiologia, Departamento de Fisiologia, Universidade Federal do Paraná, C.P. 19 031, 81 531-990, Curitiba, PR, Brazil. anete@ufpr.br
authors.forename: Anete Curte
authors.initials: AC
authors.lastname: Ferraz
authors.forename: Francesca
authors.initials: F
authors.lastname: Matheussi
authors.forename: Raphael Escorsim
authors.initials: RE
authors.lastname: Szawka
authors.forename: Vanessa
authors.initials: V
authors.lastname: Rizelio
authors.forename: Ana Márcia
authors.initials: AM
authors.lastname: Delattre
authors.forename: Paula
authors.initials: P
authors.lastname: Rigon
authors.forename: Erica do Espírito Santo
authors.initials: Edo E
authors.lastname: Hermel
authors.forename: Léder Leal
authors.initials: LL
authors.lastname: Xavier
authors.forename: Matilde
authors.initials: M
authors.lastname: Achaval
authors.forename: Janete A
authors.initials: JA
authors.lastname: Anselmo-Franci
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004298:Dopamine / Q000378:metabolism / Q000502:physiology*; D004343:Drug Implants; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006719:Homovanillic Acid / Q000378:metabolism; D008474:Medial Forebrain Bundle / Q000378:metabolism / Q000502:physiology*; D008845:Microinjections; D009474:Neurons / Q000187:drug effects*; D018696:Neuroprotective Agents; D010052:Ovariectomy; D016627:Oxidopamine; D011247:Pregnancy; D051381:Rats; D013378:Substantia Nigra / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013566:Sympathomimetics
chemical_list: D004343:Drug Implants; D004967:Estrogens; D018696:Neuroprotective Agents; D013566:Sympathomimetics; D004958:Estradiol; D016627:Oxidopamine; D004298:Dopamine; D006719:Homovanillic Acid