Effect Of Acute Corticosterone Administration On The Concentration Of Extracellular 5-HT In The Hippocampus CA3 Of C57BL/6 Mice

Objective: Corticosterone(CORT)is an important stress hormone that regulates the hippocampal serotonin(5-HT)system.The purpose of this study was to determine the effect of acute CORT administration on the concentration of extracellular 5-HT in the hippocampal CA3,by subcutaneous injection of three doses of CORT(10,20,40 mg/kg)in male C57BL/6 mice,and to detect dynamic changes of 5-HT concentration in the hippocampal CA3 by microdialysis under physiological conditions.Methods: Twenty-two male C57BL/6 mice were randomly divided into four groups for in vivo microdialysis experiment.One group was given the vehicle as the control group,while the other three groups were subcutaneously injected with CORT of 10,20 and 40mg/kg at a dose of 5 ml/kg.Dialysate samples were collected at 20 min intervals for 4h and calcium-dependence was determined 2 h by calcium-free ACSF after sampling.The changes of 5-HT concentration in the hippocampus CA3 were detected and analyzed by HPLC-ECD.Results: There was no significant difference in 5-HT concentration in dialysate between the four groups(vehicle,10,20 and 40 mg/kg CORT)before CORT administration.The three doses of CORT increased the concentration of 5-HT in the dialysate and the maximum increase occurred at 120 min which were 20.93 ± 3.13% with10 mg/kg,42.29 ± 4.99% with 20 mg/kg and 91.87 ± 4.55% with 40 mg/kg.Conclusion: Data indicated that the acute CORT increased the concentration of extracellular 5-HT(a combination of reuptake and release)in the hippocampus CA3 region of male C57BL/6 mice with a dose-dependent nature under physiological conditions.