Assiut university Staff Researches Involvement of a capsaicin-sensitive TRPV1-independent mechanism in lipopolysaccharide-induced fever in chickens Mahmoud, ME., Shimizu, Y., Shiina, T., Nikami, T., Dosoky RM., Ahmed MM., Takewaki, T. Abstract: It has been demonstrated that capsaicin blocks lipopolysaccharide (LPS)-induced fever in mammals. In this study, we investigated TRPV1 (transient receptor potential ion channel of vanilloid subtype-1)-independent action of capsaicin on LPSinduced fever in chickens. The chicken is a valuable model for this purpose because chicken TRPV1 has been shown to be insensitive to capsaicin and thus the effects of capsaicin can be attributed to TRPV1-independent mechanisms. Administration of capsaicin (10 mg/kg, iv) to conscious unrestrained chicks at 5 days of age caused a transient decrease in body temperature. This effect of capsaicin was not observed in chicks that had been pretreated twice with capsaicin, indicating that the capsaicinsensitive pathway can be desensitized. LPS (2 mg/kg, ip) induced fever that lasted for about 2.5 h, but fever was not induced in chicks that had been pretreated with capsaicin for 2 days. The preventive effect of capsaicin on LPS-induced fever was not blocked by capsazepine, an antagonist for TRPV1, but the antagonist per se blocked the febrile response to LPS. These findings suggest that a capsaicin-sensitive TRPV1-independent mechanism may be involved in LPS-induced fever. Published In: Comparative Biochemistry and Physiology, Part A , Vol. 148, No. 3 , PP. 578–583