They measured the inflammation by Evans blue extravasation, however, no pain behavior was measured. More recently, Ahn et al. have used subcutaneous interleukin-1β (IL-1β) injections into the vibrissal pad of rats to induce mechanical allodynia in the face and were successful in behaviorally quantifying it with the air puff method (Ahn et al. 2004; Jung et al. 2006a,b; see below). The inflammatory substance tends to be chosen on the type of behavioral testing that will be performed and on the duration Inhibitors,research,lifescience,medical of the response (e.g., formalin – short – hours; CFA – long – up to a few days). Mustard oil and capsaicin have the disadvantage of

activating only a subset of nociceptive receptors while other substances such as CFA Rucaparib clinical trial result in an extensive inflammatory response which may not be consistent with features observed clinically. Nevertheless, the use of these substances is established in the studies of

inflammatory pain, Inhibitors,research,lifescience,medical and the efficacy of some clinically used drugs in abolishing the experimentally induced inflammation validates them as useful Inhibitors,research,lifescience,medical in both spinal and trigeminal pain studies (see below). Table 1 Summary of inflammatory models of orofacial pain in rodents. Table shows the different types of orofacial models with an inflammatory component in mice and rats, together with their methodology for induction of the model and behavioral testing. Only studies … Musculoskeletal disorders can have a broad inflammatory component. A variety of syndromes affecting the temporomandibular Inhibitors,research,lifescience,medical joint (TMJ) area, collectively called TMD are a common complaint (Sessle 2005). These include TMJ inflammation (often arthritis-related), joint stiffness or dislocation, and muscle pain (Zakrzewska 2009; Mujakperuo et al. 2010; Benoliel et al. 2011). The majority of TMD models involve injection of CFA or other irritant substances such as mustard oil, formalin, and carrageenan into the TMJ (Bereiter and Benetti 1996; Ren and Dubner 1999; Imbe et al. 2001; Roveroni Inhibitors,research,lifescience,medical et al.

2001; Hartwig et al. 2003). Interestingly, some TMJ disorders can lack inflammatory changes, and are associated to neuromuscular dysfunction and muscular pain (Stohler 1999; Lam et al. 2005; Cairns 2010). It is thought that peripherally acting glutamate is involved in sensitizing the nociceptors SB-3CT and thus eliciting pain (Lam et al. 2005; Sessle 2011) Peripheral, intramuscular or intraarticular glutamate injections have been used to study orofacial muscle sensitization in rats (Cairns et al. 2002; Lam et al. 2005; Ro and Capra 2006; Fischer et al. 2008) and glutamate-induced nociception in mice (Quintans-Junior et al. 2010). Glutamate injections are also used for studies of TMD in human subjects (Castrillon et al. 2008). Other orofacial muscle pain models involve the ligature of masseter muscle’s tendon (Guo et al. 2010), the injection of CFA into the masseter muscle (Ambalavanar et al.