The Journal of Physiological Sciences

, Volume 59, Issue 4, pp 291–298

Spinal cholinergic mechanism of the relieving effects of electroacupuncture on cold and warm allodynia in a rat model of neuropathic pain

Authors

  • Jung Hyuk Park
    • Department of East-West Medicine, Graduate SchoolKyung Hee University
    • Jaseng Hospital of Oriental Medicine
  • Sun Kwang Kim
    • Department of Physiology, College of Oriental MedicineKyung Hee University
    • BK21 Oriental Medical Science CenterKyung Hee University
  • Ha Neul Kim
    • Department of East-West Medicine, Graduate SchoolKyung Hee University
    • Jaseng Hospital of Oriental Medicine
  • Boram Sun
    • Department of East-West Medicine, Graduate SchoolKyung Hee University
  • Sungtae Koo
    • Department of Medical ResearchKorea Institute of Oriental Medicine
  • Sun Mi Choi
    • Department of Medical ResearchKorea Institute of Oriental Medicine
  • Hyunsu Bae
    • Department of Physiology, College of Oriental MedicineKyung Hee University
    • BK21 Oriental Medical Science CenterKyung Hee University
    • Department of East-West Medicine, Graduate SchoolKyung Hee University
    • Department of Physiology, College of MedicineKyung Hee University
Original Paper

DOI: 10.1007/s12576-009-0035-9

Cite this article as:
Park, J.H., Kim, S.K., Kim, H.N. et al. J Physiol Sci (2009) 59: 291. doi:10.1007/s12576-009-0035-9

Abstract

This study was performed to determine whether spinal cholinergic systems mediate the relieving effects of electroacupuncture (EA) on cold and warm allodynia in a rat model of neuropathic pain. For neuropathic surgery, the right superior caudal trunk was resected at the level between the S1 and S2 spinal nerves innervating the tail. Two weeks after the injury, the intrathecal (i.t.) catheter was implanted. Five days after the catheterization, the rats were injected with atropine (non-selective muscarinic antagonist, 30 μg), mecamylamine (non-selective nicotinic antagonist, 50 μg), pirenzepine (M1 muscarinic antagonist, 10 μg), methoctramine (M2 antagonist, 10 μg) or 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) (M3 antagonist, 10 μg). Ten minutes after the injection, EA was applied to the ST36 acupoint for 30 min. The cold and warm allodynia were assessed by the tail immersion test [i.e., immersing the tail in cold (4°C) or warm (40°C) water and measuring the latency of an abrupt tail movement] before and after the treatments. The i.t. atropine, but not mecamylamine, blocked the relieving effects of EA on cold and warm allodynia. Furthermore, i.t. pirenzepine attenuated the antiallodynic effects of EA, whereas methoctramine and 4-DAMP did not. These results suggest that spinal muscarinic receptors, especially M1 subtype, mediate the EA-induced antiallodynia in neuropathic rats.

Keywords

Neuropathic pain Allodynia Electroacupuncture Spinal cord Cholinergic Muscarinic

Copyright information

© The Physiological Society of Japan and Springer 2009