Acupoint specificity on acupuncture regulation of hypothalamic- pituitary-adrenal cortex axis function

BACKGROUND The hypothalamus is an essential part of the brain that responds to a variety of signaling including stressful stimulations and acupuncture signals. It is also the key element of the hypothalamic-pituitary-adrenal cortex axis(HPAA). The effect of acupuncture is transmitted into the brain from the distance sensory receptor around the acupoints via peripheral nerves and body fluid. In vivo recording the activities of stress reaction neurons (SRNs, CRH-like neurons) in hypothalamic paraventricular nucleus (PVN) in response to the stimulations from different acupoints could therefore objectively reflect the acupuncture afferent effect. METHODS In this study, the electrophysiological method was adopted to record synchronously the activities of 43 CRH-like neurons after acupuncture stimulations at 33 acupoints located at the different regions. The acupoints that specifically activate certain CRH-like neurons (specificity acupoints) were selected. Furthermore, we investigated in a rat model of unpredictable chronic mild stress (UCMS) whether these specificity acupoints regulate HPAA function. The endpoints of measurement include corticosterone (CORT) level in peripheral blood, the expressions of corticotrophin releasing hormone (CRH) and glucocorticoid receptor (GR) protein in PVN and the animal behavioral performance. RESULTS Our results reveal that Shenshu (BL23), Ganshu (BL18), Qimen (LR14), Jingmen (GB25), Riyue (GB24), Zangmen (LR13), Dazui (DU14) and auricular concha region (ACR) are the specificity acupoints; and Gallbladder, Liver and Du Channels were the specificity Channels. The acupoints on Gallbladder Channel and the acupoints innervated by the same spinal cord segments as the adrenal gland demonstrated dramatic effects. CONCLUSIONS This study provides a new platform to further explore acupoints specificity in the regulation of HPAA activities.