(N-Me-Tyr1,N-Me-Arg7,D-Leu-NHEt8)-Dynorphin A (1-8) (E-2078) 是一种稳定的 Dynorphin A (1-8) 类似物，是 kappa 阿片受体 (KOR) 激动剂。

(±)-J-113397 是一种有效的、高选择性的非肽基ORL1 受体拮抗剂，对人克隆 ORL1 的Ki 为 1.8 nM。在体外，J-113397 抑制 nociceptin/orphanin FQ 刺激的GTPγS 与表达 ORL1 的 CHO 细胞结合，IC50值为 5.3 nM。J-113397 可用于研究 nociceptin/orphanin FQ 的生理作用。

Endomorphin 2 TFA, displays reasonable affinities for kappa3 binding sites, with Ki value between 20 and 30 nM. a high affinity, highly selective agonist of the μ-opioid receptor,

DAMGO is a selective peptide agonist of the µ-opioid receptor .

Nocistatin 是一种神经肽，是孤儿类阿片受体的内源性配体。 Nocistatin 还是神经肽伤害感受肽或孤啡肽 FQ (Noc/OFQ) 的功能性拮抗剂。Nocistatin 通过 Gi/o 蛋白介导途径抑制 5-HT 释放。Nocistatin 阻断 Nociceptin 诱导的异常性疼痛和痛觉过敏。

Bovine adrenal medulla docosapeptide (BAM-22P) is a potent opioid agonist, derived from the proenkephalin A gene, which is present in the adrenal medulla.

[Met5]-Enkephalin, amide, is an agonist for δ opioid receptors and putative ζ (zeta) opioid receptors. Met-enkephalin circulates in several forms, some potentially derived from proteins other than proenkephalin A, with plasma levels including both free and bound forms.

Ac-RYYRWK-NH2 is a highly effective and specific partial agonist for the nociceptin receptor (NOP). It demonstrates a remarkable affinity for rat cortical membranes ORL1, with [3H]Ac-RYYRWK-NH2 exhibiting a Kd value of 0.071 nM. However, it shows negligible affinity towards μ-, κ-, or δ-opioid receptors.

(R,S)-Ivosidenib is the less active enantiomer of Ivosidenib .