Nalfurafine analogues give peripherally biased kappa opioid pain relief
- Swapping nalfurafine's furan side chain for varied aromatics gave analogues that kept strong KOR binding and full agonism, most with G-protein bias.
- Compound 10 was inactive in thermal pain tests but gave potent KOR-mediated relief in the writhing assay and eased colitis-related colonic hypersensitivity, without notable loss of movement.
- As a P-glycoprotein substrate with limited brain exposure, it fits a peripherally restricted profile sparing central side effects.
💡 Points Based on the abstract
Being a P-gp substrate explains limited brain exposure, but that is a property, not proof the clean profile comes from peripheral restriction. Dosing with a P-gp inhibitor, or in knockout animals, would show whether central effects and sedation-type liabilities reappear. After that, bias and efficacy should be compared with other peripherally restricted KOR agonists.