BACKGROUND: This study investigates two new kappa-agonist tetrapeptides, FE 200665 and FE 200666, with high peripheral selectivity as a result of poor central nervous system penetration. METHODS: Four days after administration of Freund adjuvant into the hind paw of male Wistar rats, antinociceptive effects of intraplantar and subcutaneous injection of FE 200665 and FE 200666 were measured by paw pressure algesiometry and compared with the kappa-agonist U-69,593. Peripheral and kappa-receptor selectivity was assessed by the antagonists naloxone methiodide (NLXM) and nor-binaltorphimine, respectively. Antiinflammatory effects were evaluated by paw volume plethysmometry and histologic score. RESULTS: Similar to intraplantar U-69,593, intraplantar FE 200665 (3-100 microg) and FE 200666 (1-30 microg) resulted in significant and dose-related increases of paw pressure thresholds. Higher doses of FE 200665 (0.2-20 mg) and FE 200666 (0.06-6 mg) were required by subcutaneous route to produce similar antinociceptive responses, supporting a peripheral site of action. nor-Binaltorphimine dose-dependently antagonized this effect, implying kappa-opioid selectivity. Analgesic effects of subcutaneous FE 200665 and FE 200666 were abolished by intraplantar nor-binaltorphimine, and both subcutaneous and intraplantar effects were dose-dependently antagonized by subcutaneous NLXM, further demonstrating a peripheral site of action. One to 6 days after Freund adjuvant inoculation, single and repeated intraplantar injections of FE 200665, FE 200666, and U-69,593 significantly reduced paw volume and histologic scores. Both changes were reversed by intraplantar nor-binaltorphimine and subcutaneous NLXM. CONCLUSION: FE 200665 is a peripherally selective kappa-agonist with potent analgesic and antiinflammatory properties that may lead to improved analgesic-antiinflammatory therapy compared with centrally acting opioids or standard nonsteroidal antiinflammatory drugs.
BACKGROUND: This study investigates two new kappa-agonist tetrapeptides, FE 200665 and FE 200666, with high peripheral selectivity as a result of poor central nervous system penetration. METHODS: Four days after administration of Freund adjuvant into the hind paw of male Wistar rats, antinociceptive effects of intraplantar and subcutaneous injection of FE 200665 and FE 200666 were measured by paw pressure algesiometry and compared with the kappa-agonist U-69,593. Peripheral and kappa-receptor selectivity was assessed by the antagonists naloxone methiodide (NLXM) and nor-binaltorphimine, respectively. Antiinflammatory effects were evaluated by paw volume plethysmometry and histologic score. RESULTS: Similar to intraplantar U-69,593, intraplantar FE 200665 (3-100 microg) and FE 200666 (1-30 microg) resulted in significant and dose-related increases of paw pressure thresholds. Higher doses of FE 200665 (0.2-20 mg) and FE 200666 (0.06-6 mg) were required by subcutaneous route to produce similar antinociceptive responses, supporting a peripheral site of action. nor-Binaltorphimine dose-dependently antagonized this effect, implying kappa-opioid selectivity. Analgesic effects of subcutaneous FE 200665 and FE 200666 were abolished by intraplantar nor-binaltorphimine, and both subcutaneous and intraplantar effects were dose-dependently antagonized by subcutaneous NLXM, further demonstrating a peripheral site of action. One to 6 days after Freund adjuvant inoculation, single and repeated intraplantar injections of FE 200665, FE 200666, and U-69,593 significantly reduced paw volume and histologic scores. Both changes were reversed by intraplantar nor-binaltorphimine and subcutaneous NLXM. CONCLUSION: FE 200665 is a peripherally selective kappa-agonist with potent analgesic and antiinflammatory properties that may lead to improved analgesic-antiinflammatory therapy compared with centrally acting opioids or standard nonsteroidal antiinflammatory drugs.
Authors: Lindsey M Snyder; Michael C Chiang; Emanuel Loeza-Alcocer; Yu Omori; Junichi Hachisuka; Tayler D Sheahan; Jenna R Gale; Peter C Adelman; Elizabeth I Sypek; Stephanie A Fulton; Robert L Friedman; Margaret C Wright; Melissa Giraldo Duque; Yeon Sun Lee; Zeyu Hu; Huizhen Huang; Xiaoyun Cai; Kimberly A Meerschaert; Vidhya Nagarajan; Toshiro Hirai; Gregory Scherrer; Daniel H Kaplan; Frank Porreca; Brian M Davis; Michael S Gold; H Richard Koerber; Sarah E Ross Journal: Neuron Date: 2018-09-19 Impact factor: 17.173
Authors: Anne E Olesen; Kim Kristensen; Camilla Staahl; Sherron Kell; Gilbert Y Wong; Lars Arendt-Nielsen; Asbjørn M Drewes Journal: Clin Pharmacokinet Date: 2013-02 Impact factor: 6.447
Authors: Kelly F Paton; Diana V Atigari; Sophia Kaska; Thomas Prisinzano; Bronwyn M Kivell Journal: J Pharmacol Exp Ther Date: 2020-09-10 Impact factor: 4.030