Analgesic effects by electroacupuncture were decreased in inducible nitric oxide synthase knockout mice

Ee Hwa Kim, Hi Joon Park, Hyangsook Lee, Jung Chul Seo, Mee Suk Hong, Hun Kuk Park, Mi Hyeon Jang, Chang Ju Kim, Eunyoung Ha, Hyejung Lee, Sung Keel Kang, Sun Mi Choi, Yeon Hee Ryu, Joo Ho Chung

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Background: This study was designed to investigate the involvement of inducible nitric oxide synthase (iNOS) in electroacupuncture (EA)-induced analgesia. Methods: Two and 100 Hz EA stimulation were applied at acupoint ST 36 (Zusanli) in iNOS knockout mice (n=28). Needles were inserted 5 mm in depth in ST36. After insertion, the needles were fixed in situ with adhesive tape. EA was applied after the basal threshold determination. The EA parameters were set as follows: constant square wave current output (pulse width: 0.6 ms at 2 Hz and 0.2 ms at 100 Hz) and 2 mA intensities. EA was performed for 30 minutes and tail-flick latencies (TFLs) were evaluated every 15 minutes for 1 hour. Results: In 2 Hz EA stimulation, the tail-flick response (TFR) of wild-type mice for durations of 0, 15, 30, 45 and 60 minutes were 2.70 ± 0.26, 4.19 ± 0.37, 4.17 ± 0.34, 3.57 ± 0.27 and 3.39 ± 0.32 seconds of TFLs. Meanwhile, iNOS -/- mice showed 4.10 ± 0.33, 4.77 ± 0.24, 5.26 ± 0.30, 4.48 ± 0.33 and 5.00 ± 0.41 seconds of TFLs. In 100 Hz EA stimulation, the TFR of wild-type mice were 3.01 ± 0.24, 4.67 ± 0.31, 4.76 ± 0.25, 4.04 ± 0.45 and 4.26 ± 0.30 seconds of TFLs. The iNOS -/- mice were 4.33 ± 0.16, 5.29 ± 0.28, 5.06 ± 0.35, 4.52 ± 0.17 and 4.80 ± 0.28 seconds of TFLs. Wild-type mice exhibited 63.9% increase in TFL compared to the baseline after 2 Hz EA, whereas the iNOS knockout mice exhibited 32.9% increase in TFL. The TFL after 100 Hz EA showed similar trends: 66.5% increase in TFL in wild-type mice and 18.3% increase in the iNOS knockout mice. Conclusion: The present findings suggested that iNOS may play a crucial role in both low- and high-frequency EA-induced analgesic effects.

Original languageEnglish (US)
Pages (from-to)S28-S31
JournalNeurological research
Volume29
Issue numberSUPPL. 1
DOIs
StatePublished - 2007

Keywords

  • Analgesia
  • Electroacupuncture
  • Knockout mice
  • Nitric oxide synthase
  • Tail-flick

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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