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 4 min 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 30 min 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.

In a previous study, we showed that electroacupuncture (EA) applied to the SI-6 point on the contralateral forelimb produces long-lasting and powerful analgesia in pain caused by ankle sprain in a rat model. To investigate the underlying mechanism of EA analgesia, the present study tested the effects of various antagonists to known endogenous analgesic systems in this model. Ankle sprain was induced in anesthetized rats by overextending their right ankle with repeated forceful plantar flexion and inversion of the foot. When rats developed pain behaviors (a reduction in weight bearing of the affected hind limb), EA was applied to the SI-6 point on the contralateral forelimb for 30 minutes under halothane anesthesia. EA significantly improved the weight-bearing capacity of the affected hind limb for 2 hours, suggesting an analgesic effect. The alpha-adrenoceptor antagonist phentolamine (2 mg/kg, i.p. or 30 μg, i.t.) completely blocked the EA-induced analgesia, whereas naloxone (1 mg/kg, i.p.) and failed to block the effect. These results suggest that EA-induced analgesia is mediated by alpha-adrenoceptor mechanisms. Further experiments showed that intrathecal administration of yohimbine (10 μg), an α 2 -adrenergic antagonist, reduced the EAinduced analgesia in a dose-dependent manner, whereas terazosin (10 μg), an α 1 -adrenergic antagonist, did not produce any effect. These data suggest that the analgesic effect of EA in ankle sprain pain is, at least in part, mediated by spinal α 2 -adrenoceptor mechanisms.

Objectives: This study describes the implementation of a training course that aimed to increase the competency of undergraduate students of Korean medicine at a single college to obtain informed consent and perform bee venom acupuncture using an objective structured clinical examination (OSCE).Methods: We developed and implemented a short training course for 111 fourth-year students of Korean medicine during their clinical rotation at the Department of Acupuncture and Moxibustion Medicine. Lectures were conducted on the effects of and hypersensitivity reactions to bee venom acupuncture, obtaining informed consent, performing skin test and bee venom acupuncture. Due to the COVID-19 pandemic, some students were offered online lectures, and some could not experience the performance of OSCE in person. A survey with 16 closed and three open questions was used to investigate self-efficacy, opinions about the online lectures, and the OSCE.Results: Out of 111 questionnaires, 104 were completed (94%). Students were generally satisfied with the online lectures and OSCE. For the subjective questionnaire about what was helpful in the training of bee venom acupuncture techniques and OSCE, the authenticity of the teaching method was recorded the highest.Conclusions: This study showed that online lectures were effective in teaching clinical skills of Korean Medicine. It is necessary to produce standard educational materials for clinical skills of Korean Medicine, and studies to analyze the reliability and validity of OSCE are needed.