Effects of Electroacupuncture at Auricular Concha Region on the Depressive Status of Unpredictable Chronic Mild Stress Rat Models

Ru-Peng Liu,Zhan-Xia Huang,Hui Ben,Yufeng Zhao,Hong Meng,Pei-Jing Rong,Liang Li,Ying-Ge Ma,Bing Zhu,Xia Li,Ji-Liang Fang

doi:10.1155/2013/789674

Abstract

To explore new noninvasive treatment options for depression, this study investigated the effects of electroacupuncture (EA) at the auricular concha region (ACR) of depression rat models. Depression in rats was induced by unpredictable chronic mild stress (UCMS) combined with isolation for 21 days. Eighty male Wistar rats were randomly assigned into four groups: normal, UCMS alone, UCMS with EA-ACR treatment, and UCMS with EA-ear-tip treatment. Rats under inhaled anesthesia were treated once daily for 14 days. The results showed that blood pressure and heart rate were significantly reduced in the EA-ACR group than in the UCMS alone group or the EA-ear-tip group. The open-field test scores significantly decreased in the UCMS alone and EA-ear-tip groups but not in the EA-ACR group. Both EA treatments downregulated levels of plasma cortisol and ACTH in UCMS rats back to normal levels. The present study suggested that EA-ACR can elicit similar cardioinhibitory effects as vagus nerve stimulation (VNS), and EA-ACR significantly antagonized UCMS-induced depressive status in UCMS rats. The antidepressant effect of EA-ACR is possibly mediated via the normalization of the hypothalamic-pituitary-adrenal (HPA) axis hyperactivity.

Highlights

Vagus nerve stimulation (VNS) was approved by the U
No statistical difference was found in heart rate and blood pressure among rats of the three unpredictable chronic mild stress (UCMS) groups at the beginning of the study
Both of the heart rate and blood pressure in three UCMS groups showed a descending trend during the anesthesia period

Summary

Introduction

Vagus nerve stimulation (VNS) was approved by the U. Its mechanisms of antidepressant action are not fully elucidated; its neuromechanisms are based on the direct stimulation of the cervical trunk of the left vagus nerve. Fibers of SN project to the neuroendocrine systems in the limbic system structures and the autonomic nervous system. These areas are strongly interconnected by monoamine-related pathways, including the ventral tegmental area, brainstem, the hypothalamus, thalamus, amygdala, anterior insula, nucleus accumbens, and the lateral prefrontal cortex [5]. It is well known that the serotonergic, dopaminergic, and noradrenergic systems are commonly involved in the pathophysiology of depression and in the neuromechanisms of action of antidepressants [6]

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