Memory retention is modulated by acute estradiol and progesterone replacement.

Abstract

Ovarian hormones alter spine density of hippocampal granule and pyramidal cells in young adult and aging female rats (P. Miranda, C. L. Williams, & G. Einstein, 1999; C. S. Woolley, 1998). The present study used a delayed matching-to-place version of the water maze to investigate a behavioral correlate of these hormone-induced changes in hippocampal connectivity in 3- and 8-month-old female rats. When primed with 10-microg injections of estradiol 72 and 48 hr before testing, the memory retention of ovariectomized rats was improved compared with retention after priming with oil. A single injection of progesterone maintained this enhancement if testing occurred within 8 hr of the progesterone injection but not if testing occurred more than 24 hr after the progesterone injection. These findings indicate that estradiol and progesterone alter memory retention and suggest that these changes may be the result of hormone-induced increases in hippocampal connectivity.

Chronic stress enhances spatial memory in ovariectomized female rats despite CA3 dendritic retraction: Possible involvement of CA1 neurons

“…Acute estrogen replacement can be given 3 weeks to 4 months after OVX to observe changes in memory (Korol and Kolo, 2002;Sandstrom and Williams, 2004). Administering 17β-estradiol to OVX females either 72 and 48 h, or 48 and 24 h before behavioral assessment, which is consistent with our time frame, can either improve or impair spatial memory, depending on the task, compared with controls (Frye, 1995;Sandstrom and Williams, 2001;Korol and Kolo, 2002). Perhaps our handling procedure may have negated estrogen's effects on the Y-maze because of the enriched setting.…”

Human chorionic gonadotropin (a luteinizing hormone homologue) decreases spatial memory and increases brain amyloid-β levels in female rats

“…For example, ovariectomy (ovx) decreases spatial memory, and ovxed female rats treated with E perform better than ovxed females treated with vehicle on a number of spatial memory tasks that utilize working memory including the Morris water maze, object place memory task, and the radial arm maze (Bimonte and Denenberg, 1999;Gibbs 1999;Luine et al, 1998;Luine et al, 2003;Packard, 1998;Sandstrom and Williams, 2001;Simpkins et al, 1997).…”

Age-related changes in the expression of ER-β mRNA in the female rat brain

“…In the central nervous system, estrogen plays important roles not only in the control of reproductive actions, such as sex differentiation, but also in the regulation of a variety of nonreproductive functions, such as neuroprotection (Dluzen, 2000;Garcia-Segura et al, 2001;Behl, 2002;McEwen, 2002), synaptogenesis (Desmond and Levy, 1997;McEwen et al, 2001;Adams et al, 2001), cognition (Sherwin, 1994;Tang et al, 1996;McEwen et al, 1997;Sandstrom and Williams, 2001;Rissman et al, 2002) and fine motor skills or movement (Hampson, 1990;Jennings et al, 1998).…”