(RS)-4-Carboxyphenylglycine is a racemic mixture. (S)-4-Carboxyphenylglycine is a selective mGlu1α receptor antagonist.

β-Endorphin (1-27) (human) is an opioid antagonist that binds μ-, δ-, and κ-opioid receptors with Kis of 5.31, 6.17, and 39.82 nM, respectively. β-Endorphin (1-27) (human) inhibits β-Endorphin-induced and etorphine-induced analgesia.

BQ-3020 (TFA) is a selective ETB receptor agonist that inhibits [125I] et-1 binding to the ETB receptor in the cerebellum with a 0.2nm IC50, causing vasoconstriction.