Objectives: To evaluate the effects of electroconvulsive stimulation (ECS) on long-term potentiation (LTP) and synaptophysin (SYP) in the hippocampus of rats under chronic unpredictable mild stress (CUMS).
Methods: Sixty Sprague-Dawley rats were randomly divided into three groups (n=20 for each group): the control group (no intervention), the CUMS group (subjected to 28 days of CUMS exposure followed by 7 days of mock ECS treatment), and the CUMS+ECS group (subjected to 28 days of CUMS exposure followed by 7 days of ECS treatment). Depressive behavior was assessed by a sucrose preference test and an open-field test. The LTP levels in rat hippocampal slices were examined through electrophysiological experiments. The SYP mean density in the hippocampal CA3 region was detected by immunohistochemistry. Hippocampal SYP mRNA was assessed through reverse transcriptase-polymerase chain reaction.
Results: Chronic unpredictable mild stress diminished sucrose preference and reduced measures of locomotor activity. In addition, CUMS impaired LTP in the hippocampal CA1 region and significantly decreased SYP mean density in the hippocampal CA3 region and hippocampal SYP mRNA levels. Electroconvulsive stimulation improved these harmful behavioral effects and ameliorated LTP impairment, as well as stabilized SYP mean density in the hippocampal CA3 region and hippocampal SYP mRNA levels.
Conclusions: These results suggest that ECS can reverse the harmful behavioral effects of CUMS in rats and that the behavioral alterations induced by ECS and/or CUMS may be associated with hippocampal neuroplasticity and SYP levels.