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Density of μ‐opioid receptors in the hippocampus of adult male and female rats is altered by prenatal morphine exposure and gonadal hormone treatment
Author(s) -
Šlamberová Romana,
Rimanóczy Ágnes,
Bar Noffar,
Schindler Cheryl J.,
Vathy Ilona
Publication year - 2003
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.10076
Subject(s) - opioid , hippocampus , morphine , receptor , endocrinology , enkephalin , neuroscience , medicine , gonadal hormones , hormone , psychology , castration
The present in vitro autoradiography study demonstrates that prenatal exposure to morphine alters the density of μ‐opioid receptors in the hippocampus of adult female but not adult male rats. Prenatal morphine exposure increased the μ‐opioid receptor density in the CA1 of ovariectomized (OVX) females and in the CA3 of OVX, estradiol benzoate‐plus progesterone (EB+P)‐treated females, but decreased it in CA3 of OVX females. There were also hormonal effects on μ‐opioid receptor density in adult female rats. In the CA1, only morphine‐exposed but not saline‐exposed, hormone‐treated females (EB, P, or EB+P) had a decrease in μ‐opioid receptor density relative to OVX females. Both saline‐exposed and morphine‐exposed, OVX females after gonadal hormone replacement had a lower density of μ‐opioid receptors in the CA3 and in the dentate gyrus (DG) than OVX females. In male rats, there was a decrease in μ‐opioid receptor density in the CA1 and CA3 of gonadectomized (GNX), testosterone 17β‐proprionate (TP)‐treated males relative to GNX males regardless of prenatal morphine exposure. In the DG, the μ‐opioid receptor density was reduced only in morphine‐exposed but not in saline‐exposed, TP‐treated males compared with GNX males. Thus, our data demonstrate that μ‐opioid receptor density in the hippocampus is affected by prenatal morphine exposure and by male and female gonadal hormones. Hippocampus 2003;13:461–471. © 2003 Wiley‐Liss, Inc.