Hippocampal BDNF signaling is required for the antidepressant effects of perillaldehyde

Background: Perillaldehyde is one of the main components in perilla. Previous studies have shown that perillaldehyde exerted an antidepressant effect in mice, some of which is mediated through regulation of the anti-inflammatory system and the monoamine system. The primary objective of this study was to investigate the possible effects of perillaldehyde on the neurotrophic system and to elucidate whether its antidepressant effect requires brain-derived neurotrophic factor (BDNF) signaling. Methods: Mice were exposed to chronic unpredictable mild stress (CUMS) and orally administrated with perillaldehyde for 4 weeks for behavioral testing. Results: Perillaldehyde not only reversed the decrease in sucrose preference but also attenuated the increase in feeding latency. In addition, perillaldehyde can attenuate the reduction of CUMS-induced hippocampal BDNF levels. Our further study found that the BDNF receptor tropomyosin receptor kinase B (TrkB) antagonist K252a completely blocked the antidepressant effect of perillaldehyde in mice. Biochemical analysis showed that K252a pretreatment completely prevented the improvement of BDNF, extracellular signal-regulated kinase (ERK) phosphorylation and synaptic protein. Conclusions: These results indicated that activation of BDNF-ERK signaling in the hippocampus was required, at least in part for the antidepressant effects of perillaldehyde. (C) 2019 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.