Failure of estrogen to protect the substantia nigra pars compacta of female rats from lesion induced by 6-hydroxydopamine

Laboratório de Fisiologia e Farmacologia do Sistema Nervoso Central, Departamento de Fisiologia e Farmacologia, Universidade Federal do Paraná, CP 19.031, 81.531-990 Curitiba, PR, Brazil.
Brain Research (Impact Factor: 2.84). 11/2003; 986(1-2):200-5. DOI: 10.1016/S0006-8993(03)03198-6
Source: PubMed


The immunostaining for tyrosine hydroxylase (TH) in the substantia nigra pars compacta (SNpc) and in the ventral tegmental area (VTA) after intranigral infusion of 6-hydroxydopamine (6-OHDA, 6 microg/side) was analyzed in ovariectomized adult female Wistar rats. Estrogen replacement for 52 days (400-microg 17-beta-estradiol capsules) did not prevent the loss of TH-immunoreactive cells induced by 6-OHDA in the SNpc. This result indicates that the neuroprotective effect of dopaminergic mesencephalic cells is not observed with long-term estrogen replacement.

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Available from: Anete C Ferraz, Jan 22, 2015
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    • "Depletion of striatal DA in PD is presumed to reflect degeneration and loss of DAergic cells in the SNc, so one would expect that the marked effects of gonadectomy and hormone treatments on striatal DA lesions in experimental PD would be reflected by qualitatively similar changes in DA perikarya in the SNc. However, despite the substantial evidence that systemic hormonal status affects striatal DA loss (Sections 4.1 and 4.2; Fig. 1A and C), the survival of TH-IR cells in the partially lesioned SNc was unaffected in either sex, whether animals were gonad-intact, gonadectomised or gonadectomised and treated with estradiol, DHT or vehicle (Fig. 1B and D) (McArthur et al., 2007; Moroz et al., 2003; Ferraz et al., 2003, 2008). Additionally, estradiol failed to protect against 6- OHDA-induced DA cell loss in primary, serum-free mesencephalic cultures (Callier et al., 2002). "
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