Substance P is known to exert various pro-inflammatory effects that are mediated by neurokinin-1 (NK-1) receptor in peripheral tissues. This study examined the effect of the NK-1 receptor antagonist cis-2-[diphenylmethyl]-N-[(2-iodophenyl)-1-azabicyclo[2.2.2]octan-3-amine] (L-703,606) on nociceptive response following carrageenan injection (2%, 50 μl) into the knee joint cavity of the right hind leg. L-703,606 injection (0.1 or 1 mM, 50 μl) into the same joint cavity immediately before the carrageenan injection significantly reduced the nociceptive response. However, antagonist treatment at 5 h after carrageenan injection was ineffective in alleviating nociception. Neither intraperitoneal injection of the antagonist (1 mM, 50 μl) immediately before the carrageenan injection was effective. These results suggest that local NK-1 receptor contributes to the induction, but not maintenance, of arthritic pain.
Bibliographical noteFunding Information:
This study was supported by a grant of the Korea Health 21 R&D Project, Ministry of Health and Welfare, Republic of Korea (HMP-00-b-21300-0202) and the Brain Korea 21 Project in 2001.
- Substance P
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