Preventing Extracellular Diffusion of Trigeminal Nitric Oxide Enhances Formalin-induced Orofacial Pain.
10.4196/kjpp.2009.13.5.379
- Author:
Hwi Seok JUNG
1
;
Hong Bin JEON
;
Ik Sung JEON
;
Bum Jun LEE
;
Hyun Woo YOO
;
Dong Kuk AHN
;
Dong Ho YOUN
Author Information
1. Department of Oral Physiology, School of Dentistry, Kyungpook National University, Daegu 700-412, Korea. dyoun@knu.ac.kr
- Publication Type:Original Article
- Keywords:
Nitric oxide;
Orofacial pain;
Formalin test;
Central mechanism
- MeSH:
Animals;
Cell Membrane;
Central Nervous System;
Cyclic N-Oxides;
Diffusion;
Facial Pain;
Formaldehyde;
Guanylate Cyclase;
Horns;
Imidazoles;
Indoles;
Maleimides;
Neurons;
NG-Nitroarginine Methyl Ester;
Nitric Oxide;
Nitric Oxide Synthase;
Nociception;
Pain Measurement;
Protein Kinase C;
Rats;
Spinal Cord;
Trigeminal Nuclei
- From:The Korean Journal of Physiology and Pharmacology
2009;13(5):379-383
- CountryRepublic of Korea
- Language:English
-
Abstract:
Nitric oxide (NO), a diffusible gas, is produced in the central nervous system, including the spinal cord dorsal horn and the trigeminal nucleus, the first central areas processing nociceptive information from periphery. In the spinal cord, it has been demonstrated that NO acts as pronociceptive or antinociceptive mediators, apparently in a concentration-dependent manner. However, the central role of NO in the trigeminal nucleus remains uncertain in support of processing the orofacial nociception. Thus, we here investigated the central role of NO in formalin (3%)-induced orofacial pain in rats by administering membrane-permeable or -impermeable inhibitors, relating to the NO signaling pathways, into intracisternal space. The intracisternal pretreatments with the NO synthase inhibitor L-NAME, the NO-sensitive guanylate cyclase inhibitor ODQ, and the protein kinase C inhibitor GF109203X, all of which are permeable to the cell membrane, significantly reduced the formalin-induced pain, whereas the membrane-impermeable NO scavenger PTIO significantly enhanced it, compared to vehicle controls. These data suggest that an overall effect of NO production in the trigeminal nucleus is pronociceptive, but NO extracellularly diffused out of its producing neurons would have an antinociceptive action.
