Abstract:Objective: To investigate the effects of tamoxifen on learning and memory abilities in female rats after intraperitoneal (i.p.) injection of the selective estrogen receptor modulator tamoxifen.Methods: Adult female Sprague-Dawley (SD) rats (n=60) were randomly assigned into 5 groups (control group, vehicle group, TC 2.5 mg•kg-1 group, TC 5 mg•kg-1 group and TC 10 mg•kg-1 group). Morris water maze test, step-down test and 8-arm maze task were used to test the effects of tamoxifen on spatial learning and memory ability, passive avoidance conditioned reflex ability and active learning and memory ability in female SD rats, respectively.Results: Compared with vehicle group, passive avoidance conditioned reflex ability of the rats after i.p. injection of TC for three weeks was significantly decreased (P<0.05). After six weeks of drug treatment, the discriminability on spatial learning and memory ability, passive avoidance conditioned reflex ability and active learning and memory ability were all significantly reduced in these female SD rats (P<0.05).Conclusion: The results suggested that after tamoxifen treatment for six weeks, the learning and memory abilities in female SD rats were dose-dependently decreased, and that tamoxifen could cause substantial learning and memory deficits in female SD rats.

Key words:tamoxifen,learning and memory,female,rats,selective estrogen receptor modulators