Inhibition of adjuvant-induced inflammatory hyperalgesia in rats by local injection of neurotrophin-3.
The induction of nerve growth factor (NGF) in inflammatory tissue has been shown to be involved in hyperalgesia. In the present study, the role of neurotrophin-3 (NT-3) in the regulation of inflammatory hyperalgesia was analyzed. Inflammatory hyperalgesia was induced by intraplantar injection of complete Freund's adjuvant (CFA) to the rat hind paw. NT-3 levels in the plantar skin were much higher than NGF levels (1.24 and 0.14 ng/g tissue, respectively) before CFA injection, but decreased significantly 6 h to 48 h after the injection while NGF was markedly induced at 6 h but decreased thereafter. When 1 microg of NT-3 was locally injected at 5 h after CFA injection at the time NT-3 levels decreased, hyperalgesia was reversed transiently but specifically. These results suggest an inhibitory role of NT-3 in the regulation of pain sensitivity.
Watanabe
M
M
Department of Pharmacy, Branch Hospital, Faculty of Medicine, University of Tokyo, Mejirodai 3-28-6, Bunkyo-ku, Tokyo, Japan.
Endo
Y
Y
Kimoto
K
K
Katoh-Semba
R
R
Arakawa
Y
Y
D000818:Animals; D005620:Freund's Adjuvant; D006614:Hindlimb; D006930:Hyperalgesia / Q000276:immunology / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D007249:Inflammation / Q000276:immunology / Q000378:metabolism*; D008297:Male; D020932:Nerve Growth Factor / Q000378:metabolism / Q000494:pharmacology; D020933:Neurotrophin 3 / Q000378:metabolism* / Q000494:pharmacology; D010147:Pain Measurement; D051381:Rats; D017208:Rats, Wistar
D020933:Neurotrophin 3; D005620:Freund's Adjuvant; D020932:Nerve Growth Factor