title: Role of steroid hormones and morphine treatment in the modulation of opioid receptor gene expression in brain structures in the female rat.
abstract: This study determined the effects of acute treatment with morphine on the expression of the Oprm1, Oprk1, and Oprd1 genes (which encode μ, κ, and δ receptors, respectively) in the striatum, hypothalamus, and periaqueductal gray (PAG) in ovariectomized female rats treated with estrogen. Ovariectomized female rats were divided into five equal groups. Two groups received estrogen (50 µg/kg, 54 h before testing) and saline (ES group) or 3.5 mg/kg morphine (EM group) 2 h before euthanasia. The SS group received saline solution 54 and 2 h before the experiments. The SM group received saline 54 h and 3.5 mg/kg morphine 2 h before the experiments. The W group remained undisturbed. The genes expression were evaluated. Oprm1 and Oprk1 expression were activated, respectively, in the hypothalamus and PAG and in the striatum and PAG by morphine only in estrogen-treated animals. Oprd1 expression in the hypothalamus and PAG was activated by morphine in both estrogen-treated and -nontreated animals. The Oprm1 and Oprk1 gene response to morphine might depend on estrogen, whereas the Oprd1 gene response to morphine might not depend on estrogen, supporting the hypothesis of a functional role for ovarian hormones in opioid receptor-mediated functional adaptations in the female brain.
authors.affiliation: Instituto de Ciências da Saúde, Universidade Paulista, UNIP, Dr. Bacelar, São Paulo, CEP 04026-002 Brazil.
authors.forename: Wesley Soares
authors.initials: WS
authors.lastname: Cruz
authors.affiliation: Instituto de Ciências da Saúde, Universidade Paulista, UNIP, Dr. Bacelar, São Paulo, CEP 04026-002 Brazil.
authors.forename: Lucas Assis
authors.initials: LA
authors.lastname: Pereira
authors.affiliation: Instituto de Ciências da Saúde, Universidade Paulista, UNIP, Dr. Bacelar, São Paulo, CEP 04026-002 Brazil.
authors.forename: Luana Carvalho
authors.initials: LC
authors.lastname: Cezar
authors.affiliation: Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes 2415, Cidade Universitária, SP CEP 05508-900 Brazil.
authors.forename: Rosana
authors.initials: R
authors.lastname: Camarini
authors.affiliation: Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, Cidade Universitária, CEP 05508 270 Brazil.
authors.forename: Luciano Freitas
authors.initials: LF
authors.lastname: Felicio
authors.affiliation: Instituto de Ciências da Saúde, Universidade Paulista, UNIP, Dr. Bacelar, São Paulo, CEP 04026-002 Brazil ; Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Av. Dos Estados, 5001, Santo André, CEP 09210-971 Brazil ; Av dos Estados, 5001, Santo André, SP CEP 09210-970 Brazil.
authors.forename: Maria Martha
authors.initials: MM
authors.lastname: Bernardi
authors.affiliation: Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Av. Dos Estados, 5001, Santo André, CEP 09210-971 Brazil.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Teodorov
keywords: Estrogen; Hypothalamus; Opioid; Periaqueductal gray; Progesterone; Striatum