title: Masseter inflammation differentially regulates three nitric oxide synthases in the rat trigeminal subnucleus caudalis.
abstract: OBJECTIVE
  The aim of the present study was to evaluate changes in expression levels of three nitric oxide synthases (NOSs), namely inducible NOS (iNOS), neuronal NOS (nNOS) and endothelial NOS (eNOS), in the subnucleus caudalis of the trigeminal sensory nuclear complex (Vc) under experimental myositis conditions.
  
  
  METHODS
  Male Sprague Dawley rats were injected with an inflammatory agent, complete Freund's adjuvant (CFA), or capsaicin in the masseter muscle. The brainstem region containing the Vc was extracted at both immediate (30 and 60 min) and longer (1, 3, 7 days) time points to examine the changes in the three NOS protein levels via the Western blot technique. Subsequently, the RT-PCR experiments were carried out to verify the changes in iNOS mRNA.
  
  
  RESULTS
  Following the injections of CFA, there were no significant changes in the level of the three NOS proteins at the immediate time points. However, there was a significant upregulation of iNOS mRNA and protein 3 days after CFA-induced inflammation. Neither nNOS nor eNOS showed significant changes in the protein level at any of the longer time points. Capsaicin injection in the masseter, which we recently reported to upregulate all three NOS at the immediate time points, did not result in significant changes at longer time points.
  
  
  CONCLUSIONS
  Acute and chronic muscle inflammation differentially modulates the expression of the three NOS in the Vc. These data suggest that the contribution of each NOS in craniofacial muscle pain processing under inflammatory conditions may be anticipated with distinct temporal profiles.
authors.affiliation: Kyung Hee University, School of Dentistry, Department of Oral Medicine, 1 Hoegi Dong, Dongdaemun Gu, Seoul, Republic of Korea.
authors.forename: Yang Hyun
authors.initials: YH
authors.lastname: Chun
authors.forename: Q-Schick
authors.initials: QS
authors.lastname: Auh
authors.forename: Jongseok
authors.initials: J
authors.lastname: Lee
authors.forename: Jin Y
authors.initials: JY
authors.lastname: Ro
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D002211:Capsaicin / Q000494:pharmacology; D008297:Male; D008406:Masseter Muscle / Q000378:metabolism*; D009220:Myositis / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014275:Trigeminal Caudal Nucleus / Q000378:metabolism*
chemical_list: D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D002211:Capsaicin