Cyanopindolol is an β3-adrenoceptor antagonist. Cyanopindolol is a potent and selective antagonist at the presynaptic serotonin autoreceptor in the rat brain cortex. Cyanopindolol has binding affinity for 5-HT1A and 5-HT1B receptor (Ki: 2.1 and 3 nM respectively) [1][2][3].