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Evidence-Based Complementary and Alternative Medicine
Volume 2013 (2013), Article ID 809062, 9 pages
http://dx.doi.org/10.1155/2013/809062
Research Article

Blockade of Adrenal Medulla-Derived Epinephrine Potentiates Bee Venom-Induced Antinociception in the Mouse Formalin Test: Involvement of Peripheral β-Adrenoceptors

1Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
2Department of Maxillofacial Tissue Regeneration, School of Dentistry, Kyung Hee University, Seoul 130-701, Republic of Korea
3Department of Physiology and Brain Research Institute, Chungnam National University Medical School, Daejeon 301-747, Republic of Korea
4Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA

Received 27 March 2013; Accepted 8 August 2013

Academic Editor: Jaung-Geng Lin

Copyright © 2013 Suk-Yun Kang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The injection of diluted bee venom (DBV) into an acupoint has been used traditionally in eastern medicine to treat a variety of inflammatory chronic pain conditions. We have previously shown that DBV had a potent antinociceptive efficacy in several rodent pain models. However, the peripheral mechanisms underlying DBV-induced antinociception remain unclear. The present study was designed to investigate the role of peripheral epinephrine on the DBV-induced antinociceptive effect in the mouse formalin assay. Adrenalectomy significantly enhanced the antinociceptive effect of DBV during the late phase of the formalin test, while chemical sympathectomy had no effect. Intraperitoneal injection of epinephrine blocked this adrenalectomy-induced enhancement of the DBV-induced antinociceptive effect. Moreover, injection of a phenylethanolamine N-methyltransferase (PNMT) inhibitor enhanced the DBV-induced antinociceptive effect. Administration of nonselective β-adrenergic antagonists also significantly potentiated this DBV-induced antinociception, in a manner similar to adrenalectomy. These results demonstrate that the antinociceptive effect of DBV treatment can be significantly enhanced by modulation of adrenal medulla-derived epinephrine and this effect is mediated by peripheral β-adrenoceptors. Thus, DBV acupoint stimulation in combination with inhibition of peripheral β-adrenoceptors could be a potentially novel strategy for the management of inflammatory pain.