ABSTRACT
<p><b>AIM</b>To investigate the relationship between the spatial learning and memory and hippocampal ERK1/2 pathway activity in ovariectomized rats.</p><p><b>METHODS</b>Female SD rats were randomly divided into sham operated group (Sham group) and ovariectomized group (OVX group), and fed 4 months. Then spatial learning and memory of rats were evaluated by the Morris water maze task. Rats in each group were randomly divided into training group and untraining group before the test. Induced activity of ERK 1/2 stimulated by learning and memory was detected in the training group, and basic activity of ERK 1/2 was detected in the untraining group. The protein expression of p-ERK 1/2 and Raf kinase inhibitor protein (RKIP) were assayed by Western blotting respectively.</p><p><b>RESULTS</b>(1) During the training session the OVX rats held longer escape latenci than the sham rats did (P < 0.05). (2) The relative level of pERK1/2 protein in training rats of the both groups was higher than that in untraining rats (P < 0.05). (3) The relative level of p-ERK1/2 protein both training and untraining rats in OVX group was lower than that in sham group correspondingly (P < 0.05). (4) Compared with sham group, the relative expression of RKIP in OVX group was significantly higher (P < 0.05).</p><p><b>CONCLUSION</b>Spatial learning and memory deficits in ovariectomized rats might be correlated with the decreased basic and induced activity of ERK1/2 pathway and increased expression of RKIP in the CA1/CA2 region of hippocampus.</p>