AR-A 2 is a selective 5-HT1B receptor antagonist, with a high affinity to guinea pig cortex 5HT1B 1D and recombinant guinea pig 5-HT1B receptors (Ki: 0.24 and 0.47 nM) and with 10-fold lower affinity to guinea pig 5-HT1D receptor (Ki: 5 nM).
β3-AR agonist 1 is a highly selective, and orally available agonist of β3-adrenergic receptor (EC50: 18 nM), being inactive to β1-, β2-, and α1A-AR (β1 β3, β2 β3, and α1A β3>556-fold).