Intracisternal administration of mitogen-activated protein kinase inhibitors reduced IL-1beta-induced mirror-image mechanical allodynia in the orofacial area of rats.
The present study investigated the role of central mitogen-activated protein kinases (MAPKs) in interleukin-1beta (IL-1beta)-induced mirror-image mechanical allodynia in the orofacial area. Experiments were carried out on Sprague-Dawley rats. Under pentobarbital sodium anesthesia, a polyethylene tube was implanted in the subcutaneous area of one vibrissa pad, which enabled us to inject IL-1beta. For an intracisternal injection, each anesthetized rat was mounted on a stereotaxic frame and a polyethylene tube was implanted. Animals were given a recovery time of at least 72 h from surgery. After a subcutaneous administration of 0.01, 0.1, 1, or 10 pg of IL-1beta, we examined the face withdrawal behavioral responses produced by 10 successive trials of air puffs ipsilateral or contralateral to the IL-1beta injection site. Normal animals did not respond to pressure less than 40 psi. The thresholds of air puffs ipsilateral and contralateral to the IL-1beta injection site were significantly lower in the IL-1beta-treated group, compared with the vehicle-treated group. The decrease in the threshold of air puffs appeared 10 min after an IL-1beta injection and persisted for over 3h. Intracisternal pretreatment with PD98059, a p44/42 MAPK inhibitor, or SB203580, a p38 MAPK inhibitor, significantly reduced the decrease in the threshold of air puffs ipsilateral to the IL-1beta injection site produced by 10 pg of IL-1beta. IL-1beta-induced mirror-image mechanical allodynia was also reduced significantly by intracisternal pretreatment with both PD98059 and SB203580. These results indicate that central MAPK pathways mediate IL-1beta-induced mirror-image mechanical allodynia in the orofacial area.
Yang
Chang Sik
CS
Department of Oral Physiology and Neurobiology, School of Dentistry, Kyungpook National University, 188-1 Sam Deok 2ga, Chung-gu, Daegu 700-412, Korea.
Jung
Chang Young
CY
Ju
Jin Sook
JS
Lee
Min Kyung
MK
Ahn
Dong Kuk
DK
D000344:Afferent Pathways / Q000187:drug effects / Q000502:physiology; D000818:Animals; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005157:Facial Pain / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D006930:Hyperalgesia / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D007088:Illusions / Q000187:drug effects / Q000502:physiology; D007276:Injections, Intraventricular; D007376:Interleukin-2 / Q000037:antagonists & inhibitors*; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008465:Mechanoreceptors / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016896:Treatment Outcome; D014738:Vibrissae / Q000187:drug effects / Q000502:physiology
D004791:Enzyme Inhibitors; D007376:Interleukin-2