Table of Contents
Volume 2013, Article ID 671503, 10 pages
Research Article

Neural Mechanisms That Underlie Angina-Induced Referred Pain in the Trigeminal Nerve Territory: A c-Fos Study in Rats

1Department of Physiology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
2Department of Physical Therapy, Teikyo Heisei University Faculty of Community Health Care, 4-1 Uruido Minami, Ichihara, Chiba 290-0193, Japan

Received 31 May 2013; Accepted 8 July 2013

Academic Editors: C. M. Cendán, M. I. Díaz-Reval, C. Forster, C.-L. Hsieh, and C. Laurido

Copyright © 2013 Bunsho Hayashi 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.


The present study was designed to determine whether the trigeminal sensory nuclear complex (TSNC) is involved in angina-induced referred pain in the trigeminal nerve territory and to identify the peripheral nerve conducting nociceptive signals that are input into the TSNC. Following application of the pain producing substance (PPS) infusion, the number of Fos-labeled cells increased significantly in the subnucleus caudalis (Sp5C) compared with other nuclei in the TSNC. The Fos-labeled cells in the Sp5C disappeared when the left and right cervical vagus nerves were sectioned. Lesion of the C1-C2 spinal segments did not reduce the number of Fos-labeled cells. These results suggest that the nociceptive signals that conduct vagal afferent fibers from the cardiac region are input into the Sp5C and then projected to the thalamus.