Influence of electrical lesion of the periaqueductal gray (PAG) on the analgesic effect of emitted qi in rats

Author: Yang Kongshun//Guo Zhongliang//Xu Hong 1//Lin Housheng////
Guiyang College of Traditional Chinese Medicine, Guizhou Province, China//Guiyang College of Traditional Chinese Medicine, Guizhou Province, China//Guiyang College of Traditional Chinese Medicine, Guizhou Province, China//Shanghai Qigong Institute, Shanghai, China////
Conference/Journal: 1st World Conf Acad Exch Med Qigong
Date published: 1988
Other: Pages: 43 , Word Count: 536

Our previous work showed that the emitted qi had an analgesic effect on rats, which could be partially prevented by naloxone. The aim of the present work is to investigate the analgesic effect of the emitted qi after bilateral lesions of the ventral PAG. By means of K+ penetrating the tail of rats, the stronger the current the more K+ penetrated, the current intensity (mA) of the vocalization was taken as an indication of pain threshold. The pain threshold was decided by an average value in series of three times (interval 30 seconds). The Qigong performers emitted their qi on the head and tail of rats from their Laogong (P 8) and the index finger, with a distance of 10-30 cm for 15 minutes. After the qi stopped being emitted, pain threshold was immediately measured, then the measurement was taken every 10 minutes.

The rats Were divided into four groups: 1 ) Control group, 2) Group receiving the emitted qi, 3) Group with injection of naloxone, and 4) electrical lesion of PAG group. 6 rats were in Group III. 3 mg/kg naloxone was preinjected into the abdominal cavity of rats, then the qigong performer emitted his qi to the rats for 15 minutes. The change of pain threshold was immediately measured. 48 hours later, the same group of rats were preinjected with saline and experiments were done in the same way. 8 rats were anesthetized with phenobarbitalum natrium (30 mg/kg) . Under a stereotaxic instrument, the single pole insulated electrode was bilaterally implanted into ventral PAG, according to the rat brain atlas of J. Bures (P6.5 LRO. 0.2-0.5 H6.0-7.0). The parameters of lesion of PAG were as follows: intensity at 3 mA, time 30 sec. In 12 rats, electrode was only implanted but no lesion was done. Localization of the lesion region was identified by the Prussian blue reaction. In all of the experimental processes, a double blind method was adopted. The main results were as follows:

1. In Group I (n= 8), pain threshold was quite stable.

2. Pain threshold obviously elevated after the rats got the emitted qi for 15 minutes in 12 rats, the difference was significant as compared with the basic pain threshold of the same group (P<O.01 or P<O.001).

3. By preinjection of naloxone, pain threshold slightly elevated except 30 minutes after cease of emitting of qi. While by preinjection of saline, pain threshold obviously elevated as compared with the basic threshold of the same group, the difference was very significant (P<0.05 or P<O.01).

4. In 8 rats with destroyed bilateral ventral PAG, pain threshold had no elevation after the emitted qi was received. While in the sham lesion group, pain threshold obviously elevated after the emitted qi is received (P<O.001).

The above results showed that the analgesic effect caused by the emitted qi was obviously reduced after bilateral ventral lesions or by injecting of naloxone, indicating that PAG played an important role in emitted qi analgesia. It was regarded as a strong evidence for the participation of endogenous opiate in emitted qi analgesia. In our experiment, we also found that analgesic effect could be partially blocked by injection of opiate antagonist naloxone, suggesting that analgesic effect of the emitted qi was related to other factors. The analgesic mechanism of the emitted qi is worth further studying.