Change in the expression of hippocampal neuronal 5-hyroxytryptamine1A receptor in a mouse model of chronic restraint stress

Abstract

Objective To investigate the change in expression of hippocampal neuronal 5-hyroxytryptamine1A(5-HT1A) receptor in a mouse model of chronic restraint stress.Methods Forty BALB/c male mice aged 6-9 months weighing 25-35 g were randomly divided into 2 groups ( n =20 each): normal control group (group C) and chronic restraint stress group( group S).In group S,the model of chronic restraint stress was established described by Wood et al.Tail suspension test,light-dark test and Morris water maze test were performed respectively at 1 d after successful establishment of the model.Immobility time,staying time in light compartment,and escape latency and frequency of crossing the original platform were recorded respectively in tail suspension test,light-dark test and Morris water maze test.Then the animals were sacrificed,hippocampi were removed for determination of the expression of 5-HT1A receptor in CA1 and CA3 regions of hippocampal neurons by immuno-histochemistry.Results Compared with group C,immobility time and escape latency were significantly prolonged,staying time in light compartment was shortened,frequency of crossing the original platform was decreased,and the expression of 5-HT1A receptor in hippocampal neurons was down-regulated in group S ( P ＜ 0.05 or 0.01 ).Conclusion Chronic restraint stress can induce cognitive impairment in mice by down-regulating the expression of 5-HT1A receptor in hippocampal neurons. Key words: Stress ; Receptor, serotonin, 5- HT1 A ; Hippocampus; Neurons