title: Effect of different doses of estrogen on the nigrostriatal dopaminergic system in two 6-hydroxydopamine-induced lesion models of Parkinson's disease.
abstract: Parkinson's disease results from a degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNpc) and it is more prevalent in men than in women. Estrogen has neuroprotective action of the nigrostriatal dopaminergic (NSDA) neurons. It was investigated whether differences in plasma 17β-estradiol (E2) levels alter the degree of neuroprotection in NSDA neurons. Ovariectomized rats, implanted with subcutaneous capsules containing 400, 800 or 1,600 μg of E2 or corn oil, were injected with 1 μg of 6-OHDA in the SNpc or the medial forebrain bundle (MFB). Striatal dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and plasma E2 levels were measured. Only at 400 μg, E2 protected striatal DA against lesion of the MFB. In the SNpc, E2 failed to prevent DA depletion, but increased DOPAC/DA ratio in the striatum. In an NSDA moderate lesion, E2 has a neuroprotective action. In a severe lesion, E2 could stimulate DA activity in remaining neurons.
authors.affiliation: Laboratório de Neurofisiologia, Departamento de Fisiologia, Universidade Federal do Paraná, Curitiba, PR 81.531-990, Brazil.
authors.forename: Marcela Ferreira
authors.initials: MF
authors.lastname: Cordellini
authors.forename: Giovana
authors.initials: G
authors.lastname: Piazzetta
authors.forename: Karin Cristine
authors.initials: KC
authors.lastname: Pinto
authors.forename: Ana Márcia
authors.initials: AM
authors.lastname: Delattre
authors.forename: Francesca
authors.initials: F
authors.lastname: Matheussi
authors.forename: Ruither O G
authors.initials: RO
authors.lastname: Carolino
authors.forename: Raphael Escorsim
authors.initials: RE
authors.lastname: Szawka
authors.forename: Janete A
authors.initials: JA
authors.lastname: Anselmo-Franci
authors.forename: Anete Curte
authors.initials: AC
authors.lastname: Ferraz
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004967:Estrogens / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D010052:Ovariectomy; D016627:Oxidopamine / Q000494:pharmacology*; D010300:Parkinson Disease / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013378:Substantia Nigra / Q000187:drug effects* / Q000378:metabolism
chemical_list: D004967:Estrogens; D016627:Oxidopamine; D004298:Dopamine