Abstract
Kyotorphin(KTP) and its analog D-kyotorphin(D-KTP) which is resistant to enzyme degradation produced dose-dependent analgesic effects in the tail-pinch test when applied locally to the periaqueductal gray (PAG), nucleus reticularis paragigantocellularis(NRPG) and lumbosacral subarachnoid space(LSS) near the spinal dorsal horn in rats. ED 50 values of both dipeptides at the PAG, NRPG and LSS were: 59.0, 105 and 52.6 μg/rat for KTP, and 6.2, 8.8 and 10.6 μg/rat for D-KTP, respectively. Pretreatment with naloxone(1 mg/kg s.c.) significantly inhibited the analgesic effects of KTP and D-KTP at the PAG and LSS but not at the NRPG. Simultaneous administration of bestatin (2.5 or 50 μg) with KTP enhanced the analgesic effect of KTP in the PAG and LSS but not in the NRPG. These findings suggest that the analgesic actions of KTP and D-KTP result from two different mechanisms, 1)enkephgalin-releasing mechanism in the PAG and spinal dorsal horn, and 2)a mechanism without involvement of enkephalin-releasing actions in the NRPG.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
