Monitoring the Autonomic Nervous System and HRV in rats after Acupuncture

I often don't know what to make of these studies, but find them super interesting nonetheless, and somehow can't help but incorporate their findings into my practice for better or for worse. What I love about this study is that they actually saw a difference between electroacupuncture on Stomach 36 and Pericardium 6, both in pain reduction and autonomic response as measured by heart rate, LF(low frequency portion of HRV) and LF/HR (low frequency to high frequency ratio-a common measure of stress response.) They saw no reduction when using Liver 3 nor the sham, non-acupoint. I wish we had more studies like this, comparing one set of points and another. For one, it helps get away from the ever present placebo problem in research, and for two it might help inform our practice!!
The study model is 4 groups, sham point, Stomach 36, Pericardium 6, Liver 3, 9 rats in each group. They used alternating 2Hz/15Hz electro, (got to haul out my alternating device again...)
The abstract for the study follow. The emphases are mine. Poor rats...

(To read more about acupuncture, HRV, and my practice, please click here.

Zhen Ci Yan Jiu. 2010 Oct;35(5):335-41.
[Effects of electroacupuncture of different acupoints on changes of blood pressure and autonomic nerve system after colorectal distension in rats].

Chen SP, Gao YH, Yu XC, Liu JL.
Institute of Acu-moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China.
Abstract

OBJECTIVE: To observe the influence of electroacupuncture (EA) of different acupoints on changes of mean arterial pressure (MAP), heart rate (HR) and heart rate variability (HRV) in colorectal distension (CRD) rats, so as to analyze the specificity of actions of acupoints in relieving visceral pain and regulating activities of the autonomic nerve system.

METHODS: Forty-five Wistar rats were randomized into control, Zusanli (ST 36), non-acupoint, Neiguan (PC 6) and Taichong (LR 3) groups (n = 9/group). Under anesthesia, CRD was given to the rats by using an aerostat for 5 min. EA (2 Hz/15 Hz, 2 mA) was applied to bilateral ST 36, non-acupoint (1.0 cm lateral to ST 36), PC 6 and LR 3 for 15 min, respectively. Electrocardiogram of the cervico-chest lead was recorded by using a bioelectric amplifier, and MAP recorded by using a pressure transducer and an amplifier. Low frequency and high frequency of HRV were analyzed by Chart 5.0.

RESULTS: Following CRD, the HR, MAP, LF and LF/HF levels increased significantly in all the 5 groups (P <> 0.05). Compared with the control group, 5 min and 15 min after EA ,and 10 min after ceasing EA, MAP values of ST 36 and PC 6 groups were decreased obviously (P < style="font-weight: bold;">The LF levels of both ST 36 and PC 6 groups at 5 min after EA, and those of ST 36, PC 6 and LR 3 at 15 min after EA were significantly lower than those of control group (P <> 0.05).

CONCLUSION: EA of ST 36 and PC 6 can suppress CRD-induced increase of MAP, HR and LF/HF, suggesting beneficial effects of EA in relieving visceral pain and mediating autonomic nerve system. The aforementioned effects of EA of LR 3 and non-acupoint are not obvious.