Susana Isabel Ferreira da Silva de Sá ESTROGÉNIOS E ...

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1989; Krettek and Price, 1978), bed nuclei of the stria terminalis
(Delville and Blaustein, 1993; Dong and Swanson, 2004; Gu et al.,
2003), medial preoptic nucleus (Delville and Blaustein, 1993;
Fahrbach et al., 1989; Simerly and Swanson, 1988), ventral
subiculum (Canteras and Swanson, 1992; Fahrbach et al., 1989)
and some hypothalamic (Canteras et al., 1992; Záborsky and
Makara, 1979) and brainstem (Delville and Blaustein, 1993)
nuclei.
The purpose of the present study was to examine if the estrogen
effects on synapse formation and expression of PRs by VMNvl
neurons are a consequence of local effects of estrogen, are
mediated by trans-synaptic signaling mechanisms or are the result
of convergent regulatory influences mediated by both. To examine
these possibilities, we have surgically isolated the right VMN in
ovariectomized rats. Rats were later treated with either vehicle or
estradiol benzoate in a dose and schedule known to be
behaviorally effective and to induce synaptogenesis in the VMNvl
(Sá et al., 2009). The role played by VMN afferents in mediating
the influence of estrogens in the VMNvl was evaluated by
comparatively analyzing the number of spine and dendritic
synapses established per neuron and the number of PR-
immunoreactive neurons in the deafferented VMNvl, in the VMNvl
of the contralateral hemisphere, and in the VMNvl of control rats.
2. Results
2.1. Hormone levels and uterine weight
The uterine weight, expressed in g (SD), was 0.252 (0.08) in oil-
treated rats and 1.141 (0.25) in estradiol benzoate- (EB) treated
Fig. 1 - Serum hormone levels in oil- and EB-treated rats. (A) Estrogen
levels. (B) Progesterone levels. Columns represent means±SEM.
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