Ethnopharmacological relevance Cang-ai volatile oil (CAVO) is a traditional Chinese medicine (TCM) inhalational preparation for the treatment of some depressive and emotive disorders. Aim of the study This research aimed to evaluate the efficiency and possible mechanism of intranasal CAVO administration on depression in chronic unpredictable mild stress (CUMS)-induced rats compared to lavender volatile oil (LVO) treatment after CUMS exposure and bilateral olfactory bulb impairment (OBI) in rats. Materials and methods Forty depressive-like model rats induced by CUMS were evaluated by the forced swim test (FST), open field test (OFT), and sucrose preference test (SPT). The model rats were divided into five groups: CUMS (n = 8), CAVOh + CUMS (n = 8), CAVOl + CUMS (n = 8), LVO + CUMS (n = 8), and OBI + CAVO + CUMS (n = 8). The CUMS-induced rats were treated for a period of 4 weeks. The other healthy rats were regarded as the control (CTR, n = 8) subjects. The levels of serotonin (5-HT) and dopamine (DA) and their respective metabolites homovanillic acid (HVA) and 5-hydroxyindol acetic acid (5-HIAA) were measured in brain tissue homogenates of CUMS-induced rats using enzyme-linked immunosorbent assay (ELISA). Results CAVO ameliorated depressive-like behaviors (p < 0.05 ). The levels of DA in the CUMS group were lower than those in the CTR and CAVOh groups (** p < 0.01 and * p < 0.05 ). The levels of HVA were lower in the CUMS group than in the CTR, LVO, OBI + CAVOh and CAVOh groups (** p < 0.01 and * p < 0.05 ) and lower in the OBI + CAVOh group than in the CAVOh group (** p < 0.01 ). The levels of 5-HT in the CUMS group were lower than those in the CTR and CAVOh groups (** p < 0.01 ). The levels of 5-HIAA were lower in the CUMS and OBI + CAVOh groups than in the CTR, LVO and CAVOh groups (** p < 0.01 ). Conclusions CAVO can improve depressive-like behaviors concomitant with the regulation of DA and 5-HT metabolism in the brains of CUMS-induced rats.
Wei Shi,Shuge Sun,Yu Han,Yu Tang,Weishang Zhou,Xueying Du,Guangxu Liu
Recently, the ubiquitous presence of microplastics (MPs) has drawn worldwide concern over its potential threat to aquatic organisms. However, the effects of MPs on the olfactory ability of fish and the subsequent odorant evoked behaviors remain elusive. In the present study, we analyzed the potential olfactory toxicity of polystyrene (PS) MPs by assessing olfactory-driven behaviors of goldfish in response to odorants. Our results showed that the olfactory-driven behavioral responses of goldfish to L -cysteine and taurocholic acid were significantly hampered by a 28-day MP exposure. Further analysis demonstrated that exposure to MPs may suppress the expression of genes encoding olfactory G protein-coupled receptors, inhibit the enzyme activities of cation transport ATPases crucial for action potential generation, alter the in vivo contents of neurotransmitters as well as metabolites involved in the transduction of electrical signals, and cause olfactory bulb injury and neurotoxicity closely related to the processing of electrical signals. In conclusion, the results obtained in the present study suggest that MPs at environmentally relevant concentrations could impair the olfactory-mediated behavioral responses of goldfish, probably through hampering odorant identification, action potential generation, olfactory neural signal transduction, and olfactory information processing.