A highly selective kappa-opioid receptor agonist with low addictive potential and dependence liability.

Buprenorphine analogs have been synthesized. In the studies of analgesic and addictive effects in mice and [(35)S]GTPgammaS binding assay in human brain tissue, an analog of buprenorphine where the tert-butyl is replaced by a cyclobutyl moiety (16) has been identified as a selective kappa-partial agonist which gives antinociceptive effects, but has low abuse potential. The results may lead to lower degrees of dysphoria than full kappa-agonists.