5-HT(1A) receptor binding in the dorsal raphe nucleus is implicated in the anxiolytic-like effects of Cinnamomum cassia.

Yang-Hee Jung, Seung-Hwan Kwon, Sa-Ik Hong, Sung-Ok Lee, Sun-Yeou Kim, Seok-Yong Lee, Choon-Gon Jang

Index: Pharmacol. Biochem. Behav. 103(2) , 367-72, (2012)

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Abstract

Previously we reported that the 50% EtOH extract of Cinnamomum cassia (C. cassia) possesses anxiolytic-like activity in the mouse elevated plus maze (EPM) test. This activity was blocked by the 5-HT(1A) receptor antagonist, WAY 100635. Therefore, in order to investigate the effect of C. cassia on 5-HT(1A) receptor binding, quantitative autoradiography of 5-HT(1A) receptors was carried out in brains of mice treated acutely and repeatedly with C. cassia. Binding of [(3)H]8-OH-DPAT to the 5-HT(1A) receptor was investigated in the mouse brain. After a single treatment of C. cassia (750 mg/kg, p.o.), [(3)H]8-OH-DPAT binding showed a significant increase in the dorsal raphe nucleus (DRN). After repeated treatment with C. cassia (100mg/kg, once a day for 5 days, p.o.), [(3)H]8-OH-DPAT binding showed no significant change in any brain region. Taken together, the anxiolytic-like effect of the 50% EtOH extract of C. cassia might be mediated by region specific change of 5-HT(1A) receptors in the dorsal raphe nucleus.Copyright © 2012. Published by Elsevier Inc.