Acupuncture analgesia in a new rat model of ankle sprain pain

Sung Tae Koo, Young Il Park, Kyu Sang Lim, Kyungsoon Chung, Jin Chung

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

The lack of suitable experimental animal models for persistent pain showing clear acupuncture analgesia, has been the major stumbling block in the investigation of the physiological mechanisms of acupuncture analgesia. The present study developed a new rat model of ankle sprain pain and the effect of electroacupuncture (EA) on this model was examined. A common source of persistent pain in humans is the lateral ankle sprain. To model this condition, the rat's right ankle was bent repeatedly, overextending lateral ligaments, for 4min under halothane anesthesia. The rat subsequently showed swelling of the ankle and a reduced stepping force of the affected limb for the next several days. The reduced stepping force of the limb was presumably due to a painful ankle since systemic injection of morphine produced temporary improvement of weight bearing. EA was applied to the SI-6 acupuncture point on the contralateral forelimb for 30min under halothane anesthesia. After the termination of EA, behavioral tests measuring stepping force were periodically conducted during the next 4h. EA produced a 40% recovery in the stepping force of the sprained foot lasting for at least 2h. The magnitude of this improvement was equivalent to that obtained after a systemic injection of 2mg/kg of morphine and this improvement of stepping pressure was interpreted as an analgesic effect. The analgesic effect was specific to the acupuncture point since (1) the analgesic effect on the ankle sprain pain model could not be mimicked by EA applied to a nearby point, LI-4 and (2) EA applied to the SI-6 point was not effective in the knee arthritis pain model. The analgesic effect could not be blocked by systemic injection of opioid antagonists naloxone or naltrexone. These data suggest that EA produces a potent analgesic effect on the ankle sprain pain model in the rat. This analgesic effect is produced by applying EA to a site remote from the painful area in a stimulus point-specific way. The present study provides a powerful experimental animal model that can be used for investigating the unique physiological mechanisms involved in acupuncture analgesia.

Original languageEnglish (US)
Pages (from-to)423-431
Number of pages9
JournalPain
Volume99
Issue number3
DOIs
StatePublished - Oct 2002

Fingerprint

Acupuncture Analgesia
Ankle Injuries
Electroacupuncture
Analgesics
Pain
Ankle
Acupuncture Points
Halothane
Morphine
Injections
Extremities
Anesthesia
Animal Models
Collateral Ligaments
Naltrexone
Narcotic Antagonists
Forelimb
Weight-Bearing
Naloxone
Arthritis

Keywords

  • Analgesic effect
  • Ankle sprain pain model
  • Electroacupuncture

ASJC Scopus subject areas

  • Clinical Neurology
  • Psychiatry and Mental health
  • Neurology
  • Neuroscience(all)
  • Pharmacology
  • Clinical Psychology

Cite this

Acupuncture analgesia in a new rat model of ankle sprain pain. / Koo, Sung Tae; Park, Young Il; Lim, Kyu Sang; Chung, Kyungsoon; Chung, Jin.

In: Pain, Vol. 99, No. 3, 10.2002, p. 423-431.

Research output: Contribution to journalArticle

Koo, Sung Tae ; Park, Young Il ; Lim, Kyu Sang ; Chung, Kyungsoon ; Chung, Jin. / Acupuncture analgesia in a new rat model of ankle sprain pain. In: Pain. 2002 ; Vol. 99, No. 3. pp. 423-431.
@article{0f5f7d9d1ce0466ab1d1b687a050eb77,
title = "Acupuncture analgesia in a new rat model of ankle sprain pain",
abstract = "The lack of suitable experimental animal models for persistent pain showing clear acupuncture analgesia, has been the major stumbling block in the investigation of the physiological mechanisms of acupuncture analgesia. The present study developed a new rat model of ankle sprain pain and the effect of electroacupuncture (EA) on this model was examined. A common source of persistent pain in humans is the lateral ankle sprain. To model this condition, the rat's right ankle was bent repeatedly, overextending lateral ligaments, for 4min under halothane anesthesia. The rat subsequently showed swelling of the ankle and a reduced stepping force of the affected limb for the next several days. The reduced stepping force of the limb was presumably due to a painful ankle since systemic injection of morphine produced temporary improvement of weight bearing. EA was applied to the SI-6 acupuncture point on the contralateral forelimb for 30min under halothane anesthesia. After the termination of EA, behavioral tests measuring stepping force were periodically conducted during the next 4h. EA produced a 40{\%} recovery in the stepping force of the sprained foot lasting for at least 2h. The magnitude of this improvement was equivalent to that obtained after a systemic injection of 2mg/kg of morphine and this improvement of stepping pressure was interpreted as an analgesic effect. The analgesic effect was specific to the acupuncture point since (1) the analgesic effect on the ankle sprain pain model could not be mimicked by EA applied to a nearby point, LI-4 and (2) EA applied to the SI-6 point was not effective in the knee arthritis pain model. The analgesic effect could not be blocked by systemic injection of opioid antagonists naloxone or naltrexone. These data suggest that EA produces a potent analgesic effect on the ankle sprain pain model in the rat. This analgesic effect is produced by applying EA to a site remote from the painful area in a stimulus point-specific way. The present study provides a powerful experimental animal model that can be used for investigating the unique physiological mechanisms involved in acupuncture analgesia.",
keywords = "Analgesic effect, Ankle sprain pain model, Electroacupuncture",
author = "Koo, {Sung Tae} and Park, {Young Il} and Lim, {Kyu Sang} and Kyungsoon Chung and Jin Chung",
year = "2002",
month = "10",
doi = "10.1016/S0304-3959(02)00164-1",
language = "English (US)",
volume = "99",
pages = "423--431",
journal = "Pain",
issn = "0304-3959",
publisher = "Elsevier",
number = "3",

}

TY - JOUR

T1 - Acupuncture analgesia in a new rat model of ankle sprain pain

AU - Koo, Sung Tae

AU - Park, Young Il

AU - Lim, Kyu Sang

AU - Chung, Kyungsoon

AU - Chung, Jin

PY - 2002/10

Y1 - 2002/10

N2 - The lack of suitable experimental animal models for persistent pain showing clear acupuncture analgesia, has been the major stumbling block in the investigation of the physiological mechanisms of acupuncture analgesia. The present study developed a new rat model of ankle sprain pain and the effect of electroacupuncture (EA) on this model was examined. A common source of persistent pain in humans is the lateral ankle sprain. To model this condition, the rat's right ankle was bent repeatedly, overextending lateral ligaments, for 4min under halothane anesthesia. The rat subsequently showed swelling of the ankle and a reduced stepping force of the affected limb for the next several days. The reduced stepping force of the limb was presumably due to a painful ankle since systemic injection of morphine produced temporary improvement of weight bearing. EA was applied to the SI-6 acupuncture point on the contralateral forelimb for 30min under halothane anesthesia. After the termination of EA, behavioral tests measuring stepping force were periodically conducted during the next 4h. EA produced a 40% recovery in the stepping force of the sprained foot lasting for at least 2h. The magnitude of this improvement was equivalent to that obtained after a systemic injection of 2mg/kg of morphine and this improvement of stepping pressure was interpreted as an analgesic effect. The analgesic effect was specific to the acupuncture point since (1) the analgesic effect on the ankle sprain pain model could not be mimicked by EA applied to a nearby point, LI-4 and (2) EA applied to the SI-6 point was not effective in the knee arthritis pain model. The analgesic effect could not be blocked by systemic injection of opioid antagonists naloxone or naltrexone. These data suggest that EA produces a potent analgesic effect on the ankle sprain pain model in the rat. This analgesic effect is produced by applying EA to a site remote from the painful area in a stimulus point-specific way. The present study provides a powerful experimental animal model that can be used for investigating the unique physiological mechanisms involved in acupuncture analgesia.

AB - The lack of suitable experimental animal models for persistent pain showing clear acupuncture analgesia, has been the major stumbling block in the investigation of the physiological mechanisms of acupuncture analgesia. The present study developed a new rat model of ankle sprain pain and the effect of electroacupuncture (EA) on this model was examined. A common source of persistent pain in humans is the lateral ankle sprain. To model this condition, the rat's right ankle was bent repeatedly, overextending lateral ligaments, for 4min under halothane anesthesia. The rat subsequently showed swelling of the ankle and a reduced stepping force of the affected limb for the next several days. The reduced stepping force of the limb was presumably due to a painful ankle since systemic injection of morphine produced temporary improvement of weight bearing. EA was applied to the SI-6 acupuncture point on the contralateral forelimb for 30min under halothane anesthesia. After the termination of EA, behavioral tests measuring stepping force were periodically conducted during the next 4h. EA produced a 40% recovery in the stepping force of the sprained foot lasting for at least 2h. The magnitude of this improvement was equivalent to that obtained after a systemic injection of 2mg/kg of morphine and this improvement of stepping pressure was interpreted as an analgesic effect. The analgesic effect was specific to the acupuncture point since (1) the analgesic effect on the ankle sprain pain model could not be mimicked by EA applied to a nearby point, LI-4 and (2) EA applied to the SI-6 point was not effective in the knee arthritis pain model. The analgesic effect could not be blocked by systemic injection of opioid antagonists naloxone or naltrexone. These data suggest that EA produces a potent analgesic effect on the ankle sprain pain model in the rat. This analgesic effect is produced by applying EA to a site remote from the painful area in a stimulus point-specific way. The present study provides a powerful experimental animal model that can be used for investigating the unique physiological mechanisms involved in acupuncture analgesia.

KW - Analgesic effect

KW - Ankle sprain pain model

KW - Electroacupuncture

UR - http://www.scopus.com/inward/record.url?scp=0036803040&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036803040&partnerID=8YFLogxK

U2 - 10.1016/S0304-3959(02)00164-1

DO - 10.1016/S0304-3959(02)00164-1

M3 - Article

VL - 99

SP - 423

EP - 431

JO - Pain

JF - Pain

SN - 0304-3959

IS - 3

ER -