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

Chen Xie,Jing Wang,Wenjia Yang,Xiaolin Gao,Zhen Liu,Chaojun Fang,Na Zhao,Yunfei Chen,Xintong Yu,Xinyu Chen,Cong Fu,Sen Hu

doi:10.1155/2021/5527060

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.

Highlights

Insomnia is a highly prevalent disease that can occur at all ages, and many social or societal stressors are associated with insomnia [1]
Compared with that of the control group, the amount of wakefulness increased and NREM sleep decreased in the dirty group during the 9 h light period and 12 light period after intervention, and the difference was statistically significant (P < 0.05); compared with that of the control group, the amount of wakefulness and NREM sleep did not change in the clear group
Compared with that of the control group, the amount of wakefulness, NREM, and REM sleep changed in the clear and dirty group during the first, second, and seventh hours after cage change (P < 0.05). ese results indicate that rats placed to a dirty cage showed a significant increased amount of wakefulness and decreased amount of NREM sleep, especially in the first two hours and seventh hour after cage change, and rats placed to a clear cage still showed the amount of sleep-wake changed

Summary

Introduction

Insomnia is a highly prevalent disease that can occur at all ages, and many social or societal stressors are associated with insomnia [1]. We demonstrated that EA can improve sleep in rats after cage change through DA and the DA receptors in the HPA axis. A rat model of insomnia was established by cage change to a dirty cage. 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. 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

Methods

Results

Conclusion