Effect of the coadministration of citalopram with mirtazapine or atipamezole on rat contextual conditioned fear

Content Provider	Scilit
Author	Inoue, Takeshi Masuda, Takahiro An, Yan Takamura, Naoki Nakagawa, Shin Kitaichi, Yuji Koyama, Tsukasa Kusumi, Ichiro
Copyright Year	2014
Description	Background: Mirtazapine, a noradrenergic and specific serotonergic antidepressant, which blocks the $α_{2}$-adrenergic autoreceptors and heteroreceptors, has shown anxiolytic properties in clinical trials and preclinical animal experiments. The addition of mirtazapine to selective serotonin reuptake inhibitors (SSRIs) is clinically suggested to be more effective for anxiety disorders. In this study, we examined the combined effects of mirtazapine and citalopram, an SSRI, on the freezing behavior of rats, which was induced by contextual conditioned fear as an index of anxiety or fear. Methods: Male Sprague Dawley rats individually received footshocks in a shock chamber, and 24 hours later, they were given citalopram and/or mirtazapine injections. One hour after citalopram and 30 minutes after mirtazapine administration, freezing behavior was analyzed in the same shock chamber without shocks. Results: Mirtazapine decreased freezing in a dose-dependent manner, which is consistent with a previous report; it also enhanced an anxiolytic-like effect at a high dose (30 mg/kg) of citalopram. Because mirtazapine blocks $α_{2}$-adrenoreceptors, the combined effect of atipamezole, a selective $α_{2}$ receptor antagonist, with citalopram was also examined. Similar to mirtazapine, atipamezole reduced freezing dose-dependently, but the enhancement of citalopram's effects by atipamezole was not clear when compared with mirtazapine. Conclusion: The present findings suggest that mirtazapine has an anxiolytic-like effect and may enhance the anxiolytic-like effect of SSRIs, but this enhancement may not be explained by its $anti-α_{2}$ property alone.
Related Links	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3931693/pdf https://www.dovepress.com/getfile.php?fileID=18950
Ending Page	295
Page Count	7
Starting Page	289
ISSN	11766328
e-ISSN	11782021
DOI	10.2147/ndt.s55507
Journal	Neuropsychiatric disease and treatment
Volume Number	10
Language	English
Publisher	Informa UK Limited
Publisher Date	2014-02-01
Access Restriction	Open
Subject Keyword	Journal: Neuropsychiatric Disease and Treatment Psychiatry and Mental Health Anxiety Conditioned Fear Mirtazapine Selective Serotonin Reuptake Inhibitor Α2-adrenoreceptor
Content Type	Text
Resource Type	Article