Long-term deprivation of oestrogens by ovariectomy potentiates β-amyloid-induced working memory deficits in rats

1. In the present study, we examined whether deprivation of oestrogens by ovariectomy could modify learning and memory deficits caused by a continuous intracerebroventricular (i.c.v.) infusion of amyloid β-peptide (Aβ), the major constituent of senile plaques in AD. 2. Neither long-term (3 months) nor short-term (1 month), deprivation of oestrogens by ovariectomy caused a significant impairment in spatial learning and memory in a water maze and spontaneous alternation behaviour in a Y-maze. 3. A continuous i.c.v. infusion of Aβ-(1-42) caused spatial learning and memory deficits in both ovariectomized and sham-operated rats. 4. The Aβ-induced working memory deficits were significantly potentiated in ovariectomized rats compared with sham-operated rats when mnemonic ability was examined 3 months after ovariectomy. 5. These results suggest that long-term deprivation of oestrogens induced by ovariectomy increases susceptibility to memory deficits produced by Aβ-(1-42) in rats.