Research on the Effects of 5-HT1A Receptor in Hippocampal CA1 Region in the Cognition of PTSD Rats

Objective: Investigate the expression of 5-HT1A receptor in CA1 area of hippocampus of posttraumatic stress disorder (PTSD) rats and to explore the function of 5-HT1A receptor in the cognitive behavior of PTSD rats. Methods: 72 healthy adult SD rats were randomly divided into 4 groups: A (control group), B(model group), C(control + agonist group) and D(model + agonist group), with 18 rats in each group. The rats in B and C groups were constructed with continuous single stimulation (SPS) to construct the PTSD model rats. 2 days after the model was completed, the CA1 of the hippocampus was located under the Stereotaxic instrument. The rats of B and C groups were injected with 5-HT1A receptor agonist 8-OH-DPAT, A and B group rats were injected with equal amount of normal saline, and the dose was 0.3mg/kg. Morris water maze(MWM) was used to test the learning and memory ability in different groups of rats, The expression of 5-HT1A and 5-HT1A protein in hippocampus was examined by immunohistochemistry and immunofluorescence and Western Blot. Results: It was showed in the MWM experiment that the latency of rats in searching for the underwater platform in group C rats was significantly shorter compared with the group A(P<0.01), B and C group were increased(P<0.01). Compared with group B, group D rats escape the latency was significantly prolonged(P<0.01). The expression of 5-HT1A receptor in CA1 region of hippocampal by immunohistochemistry and immunofluorescence and Western Blot experiments all showed that, Compared with the group A, the other 3 groups were significantly increased(P<0.01), Compared with the group B, the group D was significantly increased (P<0.01), neverthelessly, there was no significant difference between the B group and the C group (P> 0.05). Conclusion: The spatial memory impairment in rats with PTSD maybe associated with the increase of the expression of 5-HT1A receptor in the CA1 region of hippocampus.