CCK RECEPTOR ANTAGONIST L-365,260 POTENTIATED ELECTROACUPUNCTURE ANALGESIA IN WISTAR RATS BUT NOT IN AUDIOGENIC EPILEPTIC RATS

Cholecystokinin octapeptide (CCK-8) has been shown to be a neuropeptide with potent anti-opioid activity. Previous studies have shown that central administration of nanogram dose of CCK-8 totally abolished morphine analgesia in the rat, an effect mediated by CCK-B receptor in central nervous system. In the present study CCK-B antagonist L-365,260 was injected intracerebroventricularly (icv) to Wistar rats to see its effect on the analgesic effect induced by electroacupuncture (EA) stimulation. A marked potentiation of EA-induced analgesia was observed. The degree of potentiation depends on the frequency of EA used, with a rank order of 100 Hz > 15 Hz = 2/15 Hz>> 2Hz. In a strain of rat with acoustically evoked epileptic seizure (P77PMC rats), an extra-ordinarily strong analgesic effect was produced in response to 100 Hz EA stimulation, which was similar to that in Wistar rats pre-treat ed with L-365,260. However, L-365,260 was not effective in potentiating EA analgesia in P77PMC rats. The results suggest that (1) high frequency EA is more likely to increase the release of CCK-8 in CNS as compared to low frequency EA, and (2) P77PMC rats may have a functional defect of the central CCK neurons in the nature of either a low CCK content or a reduced rate of release of CCK-8 in the CNS.

Acupuncture effects on the hippocampal cholinergic system in a rat model of neuropathic pain

The present study observed the effects of repeated electroacupuncture of Zusanli （ST36） and Yanglingquan （GB34） on expression of hippocampal acetylcholinesterase, vesicular acetylcholine transporter, and muscarinic M1 receptor mRNA in chronic constrictive injury （neuropathic pain） and/or ovariotomy rats. Results demonstrated increased expression of hippocampal acetylcholinesterase, vesicular acetylcholine transporter, and muscarinic M1 receptor mRNA, as well as decreased pain threshold, in a rat model of chronic neuropathic pain after electroacupuncture. The effects of electroacupuncture increased with prolonged time, but the above-mentioned effects decreased in memory-deficient animals. Results indicated that repeated electroacupuncture has a cumulative analgesic effect, which is closely associated with upregulation of acetylcholinesterase and vesicular acetylcholine transporter activity, as well as M1 receptor mRNA expression and memory.

电针镇痛及其与刺激参数的量效关系研究:近三十年研究新进展

In this review,we explored the dose-effect relationship of electroacupuncture(EA)analgesia and its stimulus parameters by searching articles on clinical and experimental research of EA analgesia in the past30 years.The impacts on the analgesic effects are discussed in terms of the pulse waveform,frequency,amplitude,wave width,and time effect,as well as parameter combinations,and the optimization of the EA parameters are summarized for the treatment of neuropathic,inflammatory,and cancer pains.It was initially discovered that the distant-dense(D-D)wave(2/15 Hz or 2/100 Hz)and stimulus for 30-45 min were appropriate in the treatment of chronic inflammatory pain,the strong stimulus was applicable to the acute stage of pain(twice a week),while the weak stimulus was for the stable stage(once weekly).The continuous(2 Hz)/D-D wave(2/100 Hz)and moderate/low intensity of stimulus for 30-45 min are preferred in the treatment of neuropathic pain with EA,once daily or every 2 days.Regarding the treatment of cancer pain,EA with continuous(2 Hz or 100 Hz)or D-D wave(2/100 Hz),moderate and low intensity of stimulus for 30-45 min is adopted,once every 2 days.There is a certain rule for the correlation of each parameter and the combination of parameters to ensure an analgesic effect of EA,which should be further explored in future studies.