Electroacupuncture-Induced Dynamic Processes of Gene Expression Levels of Endogenous Opioid Peptide Precursors and Opioid Receptors in the CNS of Goats

Abstract

In order to investigate the dynamic processes of mRNA levels of proenkephalin, proopiomelanocortin, prodynorphin, and opioid receptors (δ-, μ-, and κ-receptor) induced by electroacupuncture (EA) in the central nerve system, goats were stimulated by EA of 60 Hz for 0.5 h at a set of Baihui, Santai, Ergen, and Sanyangluo points. The pain threshold was measured using the method of potassium iontophoresis. The mRNA levels of the three opioid peptide precursors and three opioid receptors were determined with quantitative real-time PCR and the levels of Met-enkephalin with SABC immunohistochemistry at 0.5 h before and at 0, 2, 4, 6, 8, 12, and 24 h after EA. The results showed that the pain threshold correlated (P < 0.01) with Met-enkephalin immunoactivities in the measured nuclei and areas of goats. The analgesic aftereffect lasted for 12 h at least. The mRNA levels of the three opioid peptide precursors and three opioid receptors began to increase at 0 h, reached the peak during the time from 4 h to 6 h or at 12 h, and remained higher at 24 h after EA was discontinued. These results suggested that the initiation of gene expression of opioid peptides and the three receptors may be associated with EA-induced analgesic aftereffect.

The Expression Patterns of c-Fos and c-Jun Induced by Different Frequencies of Electroacupuncture in the Brain

“…These studies showed that analgesia induced by different frequencies seems to vary in species. In the present study, we used different frequencies (2, 60, and 100 Hz) to stimulate the set of “Baihui, Santai, Ergen, and Sanyangluo” acupoints in goats and found that the analgesia induced by 60 Hz was better than that by 2 or 100 Hz, which is consistent with the findings reported by Cheng et al [ 34 , 35 ].…”

Exploring the Mechanisms of Electroacupuncture-Induced Analgesia through RNA Sequencing of the Periaqueductal Gray

“…Cheng et al [ 35 ] performed different frequencies (2, 40, 60, 80 and 100 Hz) to stimulate the same set of acupoints in goats, and found that 60 Hz induced more potent analgesia than any of the other frequencies. In the present study, EA at 60 Hz was used to stimulate a set of Baihui, Santai, Ergen, and Sanyangluo acupoints in goats, which increased the nociceptive threshold by 58.80 ± 4.80% after EA stimulation, which has a similar tendency to previous studies [ 32 , 35 , 36 ].…”

Electroacupuncture is Beneficial for Primary Dysmenorrhea: The Evidence from Meta‐Analysis of Randomized Controlled Trials

“…Currently, our results suggest that EA stimulation at classic acupoint could alleviate the pain at once when compared with controls. The immediate analgesic effects of EA may be associated with the activation of the endogenous opioid system, which has been supported by plenty of experimental evidence [ 45 – 47 ].…”