Effects of experimentally induced inflammation on temporomandibular joint nociceptors in rats.
Response properties of nociceptors in the temporomandibular joint (TMJ) and surrounding area under experimental inflammation were investigated using an in vitro TMJ-nerve preparation in the rat. Nociceptive units (receptor and innervating nerve fiber) were classified into the following subtypes: Adelta-high-threshold mechanonociceptor (HTM), Adelta-polymodal nociceptor (POLY), C-HTM and C-POLY. In the inflamed joint, mechanical thresholds tended to be lower; however, the reaction to bradykinin was not identified as clearly as in control. Experimentally induced inflammation increased the proportion of heat-sensitive units and lowered heat threshold significantly. These results suggest that inflammation may sensitize nociceptors in the temporomandibular joint, and cause hyperalgesia and allodynia.
Takeuchi
Yoshinari
Y
Maxillofacial Surgery, Maxillofacial Reconstruction, Division of Maxillofacial and Neck Reconstruction, Graduate School, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8549, Japan.
Zeredo
Jorge L
JL
Fujiyama
Rie
R
Amagasa
Teruo
T
Toda
Kazuo
K
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D018771:Arthralgia / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology*; D001168:Arthritis / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology*; D001920:Bradykinin / Q000494:pharmacology; D002351:Carrageenan / Q000494:pharmacology; D004195:Disease Models, Animal; D006930:Hyperalgesia / Q000473:pathology / Q000503:physiopathology; D007616:Kaolin; D008465:Mechanoreceptors / Q000187:drug effects / Q000502:physiology; D009413:Nerve Fibers, Myelinated / Q000187:drug effects / Q000502:physiology; D036421:Nerve Fibers, Unmyelinated / Q000187:drug effects / Q000502:physiology; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology*; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D010812:Physical Stimulation; D051381:Rats; D017208:Rats, Wistar; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000502:physiology*; D013704:Temporomandibular Joint / Q000294:innervation* / Q000473:pathology / Q000503:physiopathology; D013705:Temporomandibular Joint Disorders / Q000139:chemically induced / Q000503:physiopathology*
D007616:Kaolin; D002351:Carrageenan; D001920:Bradykinin