Abstract
Background: Fast-onset antidepressants are urgently needed. Chaihu-jia-Longgu-Muli-tang (CLM), a classic Chinese herbal medicine, has been used for antidepressant treatment with long history. Olfactory bulbectomization (OB) model is validated for identification of rapid antidepressant efficacy. Here we used OB model for investigating the rapid onset activity of CLM in mice, and also tested the involvement of prefrontal Akt-mTOR and associated AMPA/NMDA receptors as well as hippocampal BDNF in the rapid antidepressant-like effect of CLM.Methods: The OB model was first characterized with depression-like behaviors and the time course changes of the behaviors. The fast onset of antidepressant effect of CLM was evaluated using sucrose preference test, tail suspension test and forced swim test in OB mice after a single administration. The expression of synaptic proteins of AMPA and NMDA subunits as well as Akt/mTOR signaling in the prefrontal cortex, and hippocampal BDNF was evaluated with the immunoblotting method.Results: A single dose of CLM significantly improved the deficiency in the sucrose preference and decreased the immobility time in the tail suspension test in OB mice. In the prefrontal cortex (PFC) in OB mice, there was lower expression level of the AMPA receptor subunit GluR1, rescued by a single dose of CLM. Additionally, the expression of NMDA subunit NR1 was up-regulated in OB mice, whereas mTOR and its upstream Akt signalings were both down-regulated. These deficiencies were reversed by a single dose of CLM. The CLM treatment also attenuated the expressions of NMDA receptor subunits NR2A and NR2B, which did not change in OB mice. In the hippocampus, expressions of GluR1 and brain derived neurotrophic factor (BDNF) were both up-regulated in OB mice, although CLM increased GluR1, but not BDNF.Conclusion: CLM elicited rapid antidepressant-like effects in the OB model mice, and CLM reversal of the abnormality in PFC expression of AMPA and NMDA receptors and associated Akt-mTOR signaling may underlie the effects.
Highlights
Major depressive disorder (MDD) is one of the most common diseases of persistent emotion stepping down, inhibition of thought and psychomotor retardation
The expression of synaptic proteins of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and NMDA subunits as well as Akt/mammalian target of rapamycin (mTOR) signaling in the prefrontal cortex, and hippocampal brain derived neurotrophic factor (BDNF) was evaluated with the immunoblotting method
The CLM treatment attenuated the expressions of NMDA receptor subunits NR2A and NR2B, which did not change in Olfactory bulbectomization (OB) mice
Summary
Major depressive disorder (MDD) is one of the most common diseases of persistent emotion (feeling) stepping down, inhibition of thought and psychomotor retardation. Ketamine (KET), a N-methyl-D-aspartic acid receptor (NMDAR) antagonist, is found to elicit fast-onset and long-lasting antidepressant effects: a single dose of KET quickly alleviates the depressive symptoms, and the effect may last for several days in both MDD patients and various animal models of depression (Zarate et al, 2006; aan het Rot et al, 2010; Li et al, 2010; Autry et al, 2011; Duman et al, 2012). We used OB model for investigating the rapid onset activity of CLM in mice, and tested the involvement of prefrontal Akt-mTOR and associated AMPA/NMDA receptors as well as hippocampal BDNF in the rapid antidepressant-like effect of CLM
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