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Published on: October 24, 2018
Serotonergic modulation of psychological stress-induced alteration in synaptic plasticity in the rat hippocampal CA1
Machiko Matsumoto1, Hiroko Togashi, Satoshi Ohashi
1Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo 060-8638, Japan. mbird@med.hokudai.ac.jp
Abstract:
In order to elucidate possible involvement of the serotonergic neuronal system in the stress-induced alteration in synaptic plasticity, the effects of contextual fear conditioning (CFC) on long-term potentiation (LTP) in the hippocampal CA1 field were examined in 5-HT-depleted rats by pretreatment with 5,7-dihydroxytryptamine (5,7-DHT, 200 microg/rat, i.c.v.). LTP induction was suppressed by footshock (FS) stimulation in 5-HT-lesioned rats and vehicle-treated controls. When rats were exposed to CFC, which was received 24 h after FS stimulation, LTP was also blocked in both-treated groups. CFC-induced impairment of LTP, however, significantly attenuated in 5-HT-lesioned rats when compared with that in controls. Fear-related freezing behavior after FS stimulation occurred similarly in both treated groups, whereas the behavior observed during exposure to CFC significantly reduced in 5-HT-lesioned rats. These results suggest that the serotonergic mechanism is involved in the psychological stress-induced alteration in synaptic plasticity, which appears to be associated with fear-related behavior.
