Analogues of the kappa (kappa) opioid receptor agonist, ICI 199441, were pr
epared. K-i values for these analogues at the cloned human kappa opioid rec
eptor ranged from 0.058 to 25 nM. Trifluoromethylaryl derivatives were pote
nt analgesics when administered subcutaneously in the rat and were more per
ipherally restricted than the parent compound, ICI 199441. (C) 2000 Elsevie
r Science Ltd. All rights reserved.