Abstract
Electroacupuncture (EA) is used to treat a variety of inflammatory diseases; however, the neurophysiological mechanisms underlying EA's anti-inflammatory effect remain unclear. Accumulating evidence suggests that the sympathetic nervous system regulates immunologic and inflammatory responses and thus we hypothesized that this system could be involved in EA's anti-inflammatory effect (EA-AI). The goal of the present study was to evaluate whether the sympathetic nervous system plays a critical role in EA-AI using a mouse air pouch inflammation model. We found that bilateral low-frequency (1 Hz) EA applied to the Zusanli acupoint significantly suppressed the number of zymosan-induced leukocytes migrating into the air pouch. Furthermore, double-labeling immunohistochemical experiments showed that EA stimulation increased Fos expression in choline acetyltransferase (ChAT)-positive sympathetic pre-ganglionic neurons in the intermediolateral region of thoracic spinal cord segments. Chemical sympathetic denervation by intraperitoneal injection of 6-hydroxydopamine (which spares sympathetic adrenal medullary innervation) significantly inhibited EA-AI. In contrast, adrenalectomy did not alter EA-AI. Finally, systemic propranolol administration significantly inhibited EA's anti-inflammatory effect, suggesting that β-adrenoceptors are involved. Collectively, these results suggest that EA produces an anti-inflammatory effect in this mouse air pouch model by activating the sympathetic nervous system leading to the release of catecholamines from post-ganglionic nerve terminals, which act on β-adrenoceptors on immune cells to inhibit their migration.
Original language | English (US) |
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Pages (from-to) | 69-75 |
Number of pages | 7 |
Journal | Brain Research |
Volume | 1148 |
Issue number | 1 |
DOIs | |
State | Published - May 7 2007 |
Bibliographical note
Funding Information:This work was supported by the SRC program of KOSEF (R11-2005-014). In addition, this study was supported by a Research Fund from the Research Institute for Veterinary Science (RIVS) in the College of Veterinary Medicine, Seoul National University.
Keywords
- Adrenalectomy
- Air pouch
- Anti-inflammatory
- Electroacupuncture
- Mouse
- Sympathetic pre-ganglionic neuron