Effects of Electroacupuncture on Sleep via the Dopamine System of the HPA Axis in Rats after Cage Change

Abstract

Background. Insomnia is often related to stressful events. The hypothalamus-pituitary-adrenal (HPA) axis is related to stress, and dopamine (DA) and DA receptors are involved in the regulation of HPA axis. Electroacupuncture (EA) can improve sleep in individuals with insomnia, but the mechanism is unclear. We demonstrated that EA can improve sleep in rats after cage change through DA and the DA receptors in the HPA axis. Methods. A rat model of insomnia was established by cage change to a dirty cage. The rats in treatment groups were intervened by EA and D1R (or D2R) antagonists. Electroencephalography (EEG) and electromyogram (EMG) were recorded to compare the changes in sleep. The DA, corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and cortisol (CORT) levels in the plasma and hypothalamus were measured by ELISAs, and the D1R and D2R levels were measured by RT-PCR and immunohistochemistry. Results. The dirty group showed a significant increase in the amount of wakefulness and decrease in the amount of NREM sleep, with decreased numbers of long NREM sleep bouts and REM sleep bouts and increased mean duration of wakefulness during the light period. EA and D1R (or D2R) antagonists intervention could improve sleep disturbance by decreasing wakefulness in the light period after cage change, EA and D1R (or D2R) antagonists could increase the hypothalamus DA, CRH, ACTH, CORT level, and the D1R and D2R mRNA levels in the HPA axis, and the effect of EA plus D1R (or D2R) antagonist was not superior to that of EA or D1R (or D2R) antagonists alone. Conclusions. EA can improve the sleep of rats after cage change, and the mechanism may be related to the regulation of DA and D1R or D2R in the HPA axis.

The effects of acupuncture on sleep disorders and its underlying mechanism: a literature review of rodent studies

“…The hypothalamic levels of DA, corticotropin-releasing hormone, adrenocorticotropic hormone (ACTH), and cortisol (CORT) increased in the EA group treated at the BL18 and ST36 acupoints. Moreover, EA treatment increased D1R and D2R mRNA levels ( Xie et al, 2021 ). The DU20, HT7, and SP6 acupoints were used for EA treatment in a rat model of insomnia.…”

“…Acupuncture therapy, which has beneficial effects on neuroprotection, has been shown to improve serum and hippocampal 5-HT and DA levels in depression model rats ( Li et al, 2021 ). Interestingly, several studies have shown increased levels of 5-HT expression in different sites, such as the serum ( Yu et al, 2022 ), hypothalamus ( Bo et al, 2017 ; Xie et al, 2021 ), and hippocampus ( Bo et al, 2017 ; Cao et al, 2022 ) following acupuncture treatment. Among these studies, one showed an improvement in both 5-HT and DA expression levels ( Xie et al, 2021 ).…”

“…Interestingly, several studies have shown increased levels of 5-HT expression in different sites, such as the serum ( Yu et al, 2022 ), hypothalamus ( Bo et al, 2017 ; Xie et al, 2021 ), and hippocampus ( Bo et al, 2017 ; Cao et al, 2022 ) following acupuncture treatment. Among these studies, one showed an improvement in both 5-HT and DA expression levels ( Xie et al, 2021 ). Moreover, according to previous reports, dopaminergic neurons are typically found in the midbrain, particularly in the VTA ( Juarez Olguin et al, 2016 ).…”

Acupuncture in circadian rhythm sleep–wake disorders and its potential neurochemical mechanisms

“…Electroacupuncture can significantly increase DA and lower TNF-α levels, so as to alleviate the immunosuppressive response and inflammatory damage of intestinal tissues and organs (Li et al, 2021). In cage-changed rats, electroacupuncture is capable of improving sleep quality by increasing the levels of DA and DA receptors in the hypothalamic-pituitary-adrenal (HPA) axis (Xie et al, 2021). 9.2 Amino acid neurotransmitters 9.2.1 γ-Aminobutyric acid GABA is a distinct neurotransmitter of the ascending inhibitory system, which is widely distributed in the CNS.…”