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Open Access Research article

Activation of amygdala opioid receptors by electroacupuncture of Feng-Chi (GB20) acupoints exacerbates focal epilepsy

Pei-Lu Yi12, Chin-Yu Lu1, Chiung-Hsiang Cheng1, Yi-Fong Tsai1, Chung-Tien Lin1* and Fang-Chia Chang134*

Author Affiliations

1 Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, No. 1, Sec. 4., Roosevelt Road, Taipei 106, Taiwan

2 Department of Sports, Health & Leisure, College of Sports Knowledge, Aletheia University, Tainan Campus, Tainan Taiwan

3 Graduate Institute of Brain & Mind Sciences, College of Medicine, National Taiwan University, Taipei Taiwan

4 Graduate Institute of Acupuncture Science, College of Chinese Medicine, China Medical University, Taichung Taiwan

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BMC Complementary and Alternative Medicine 2013, 13:290  doi:10.1186/1472-6882-13-290

Published: 29 October 2013

Abstract

Background

The effect of seizure suppression by acupuncture of Feng-Chi (GB20) acupoints has been documented in the ancient Chinese literature, Lingshu Jing (Classic of the Miraculous Pivot), however, there is a lack of scientific evidence to prove it. This current study was designed to elucidate the effect of electroacupuncture (EA) stimulation of bilateral Feng-Chi (GB20) acupoints on the epileptic activity by employing an animal model of focal epilepsy.

Methods

Administration of pilocarpine into the left central nucleus of amygdala (CeA) induced the focal epilepsy in rats. Rats received a 30-min 100 Hz EA stimulation of bilateral Feng-Chi acupoints per day, beginning at 30 minutes before the dark period and performing in three consecutive days. The broad-spectrum opioid receptor antagonist (naloxone), μ-receptor antagonist (naloxonazine), δ-receptor antagonist (naltrindole) and κ-receptor antagonist (nor-binaltorphimine) were administered directly into the CeA to elucidate the involvement of CeA opioid receptors in the EA effect.

Results

High-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints did not suppress the pilocarpine-induced epileptiform electroencephalograms (EEGs), whereas it further increased the duration of epileptiform EEGs. We also observed that epilepsy occurred while 100 Hz EA stimulation of Feng-Chi acupoints was delivered into naïve rats. EA-induced augmentation of epileptic activity was blocked by microinjection of naloxone, μ- (naloxonazine), κ- (nor-binaltorphimine) or δ-receptor antagonists (natrindole) into the CeA, suggesting that activation of opioid receptors in the CeA mediates EA-exacerbated epilepsy.

Conclusions

The present study suggests that high-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints has no effect to protect against pilocarpine-induced focal epilepsy; in contrast, EA further exacerbated focal epilepsy induced by pilocarpine. Opioid receptors in the CeA mediated EA-induced exacerbation of focal epilepsy.

Keywords:
Electroacupuncture; Feng-Chi (GB20); Epilepsy; Amygdala; Opioid receptors