UFP-101

UFP-101 is a **potent, selective, and competitive peptide antagonist** of the nociceptin/orphanin FQ receptor (**NOP receptor**, also known as **ORL1**)[3][5][2][1]. It was designed by combining the [Nphe1] chemical modification (which eliminates agonist efficacy) with Arg14 and Lys15 substitutions, resulting in high antagonist potency[5][3]. UFP-101 binds with high affinity (pKi ~10.2) and ~3000-fold selectivity over classical opioid receptors[1][3]. Its primary utility has been as a **pharmacological research tool** for dissecting the biological functions of the NOP receptor system, which regulates processes including analgesia, mood, immune response, and cardiovascular function[1][6]. In animal studies, UFP-101 blocks the effects of endogenous nociceptin/orphanin FQ, showing antinociceptive and antidepressant actions, and has been demonstrated to **reduce microvascular inflammation in models of sepsis/endotoxemia**[4][3][6].

Other names

UFP-101UFP101UFP 101[Nphe1,Arg14,Lys15]Nociceptin-NH2peptide antagonist selective for nociceptin/orphanin FQ receptor