text: Both 5'-AMN and << 5'-MABN >> had high affinity for κ-receptors (K (i) 1.36 ± 0.98 and 0.27 ± 0.08, respectively) and were revealed as potent κ-antagonists (pA(2) 7.43 and 8.18, respectively) and [[ μ-receptor ]] antagonists (pA(2) 7.62 and 7.85, respectively) in the ileum.