Abstract:Objective To investigate the effects of the aromatherapy method of hops essential oil on the behavior, content of some neurotransmitters and pineal glands on rats with insomnia caused by chlorophenylalanine (PCPA).Methods Insomnia rats were established by intraperitoneal injection of PCPA, and randomly divided into model group, lavender essential oil (0.2%) group, hops essential oil low concentration (0.05%) group, hops essential oil medium concentration (0.1%) group, and hops essential oil high concentration (0.2%) group, with 12 rats in each group and 12 rats in control group. After modeling, each treatment group was aromatherapy with corresponding concentration of essential oil, control group, and model group were aromatherapy with distilled water. Mice were fumigated for 8 hours per day for 5 days. The general condition of rats was observed. The sleep latency and sleep duration of rats were observed in pentobarbital sodium coordinated sleep experiment. Spontaneous activity was detected by open field experiment; The concentration of Melatonin (MT), γ-Aminobutyric acid (GABA), and Glutamic acid (Glu) in serum were determined by Enzyme-linked immunosorbent assay (ELISA). The concentration of norepinephrine (NE), dopamine (DA), serotonin (5-HT) in the hypothalamus of rats were determined with high performance liquid phase; The pathological changes of the pineal gland was observed by H&E staining.Results Compared with control group, model group sleep latency period extended, and sleep duration of model group were decreased (P <0.05); horizontal and vertical motion were decreased (P < 0.05). Compared with model group, sleep latency was decreased, and sleep duration was prolonged in hops essential oil concentration group (P < 0.05). Both horizontal and vertical movement were increased (P < 0.05). The concentrations of MT and GABA in serum were increased, and Glu and Glu/GABA in serum were decreased (P < 0.05). The concentrations of 5-HT in the hypothalamus increased, and NE and DA in the hypothalamus decreased (P < 0.05) The morphology and structure of pineal cells and glial cells were normal, and the number of pineal cells and glial cells recovered obviously.Conclusion Hops essential oil aromatherapy has sleep-aid effect on insomnia rats, which may be related to improve pineal structure, promote the secretion of MT, GABA, and 5-HT, and inhibit the secretion of Glu, NE, and DA.