[Expression of hemokinin-1 in rat spinal cord after peripheral inflammation].
Hemokinin-1 (HK-1) is a novel peptide described as a member of the tachykinin family. Substance P (SP), a representative member of the tachykinin family, has been well characterized and is thought to play a part in inflammation and pain. While several studies indicate that HK-1 is involved in inflammation and pain, the biological functions of HK-1 are not fully understood. In the present study we investigated the expression of HK-1 mRNA (TAC4) and SP mRNA (TAC1) in the dorsal spinal cord of rat after inducing peripheral inflammation by administering complete Freund's adjuvant (CFA) into the hind paw, using real-time RT-PCR. In the behavioral studies, the thresholds of withdrawal response of the hind paw to thermal stimulation significantly decreased on the ipsilateral side, but not on the contralateral side, 6 hours after CFA injection and thermal hyperalgesia persisted until 4 days after CFA injection. The level of HK-1 mRNA expression significantly increased on the bilateral sides of the dorsal spinal cord 6 hours after CFA injection and returned to the base level 1 day after injection. On the other hand, the level of SP mRNA expression did not change in the spinal cord 6 hours and 1 day after CFA injection. These results indicate that HK-1 may contribute to inflammatory pain, in the early phase, in a different manner from SP.
Ando
Yuko
Y
Orofacial Pain Management, Department of Oral Restitution, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University.
D000818:Animals; D007249:Inflammation / Q000378:metabolism*; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000737:chemistry*; D015320:Tachykinins / Q000032:analysis*
D012333:RNA, Messenger; D015320:Tachykinins; C507968:hemokinin-1