Penbutolol is an antagonist of β-adrenergic receptors (β-ARs; IC50 = 2.8 nM) and the serotonin (5-HT) receptor subtype 5-HT1A (IC50 = 9.9 nM).1 It inhibits adenylate cyclase activity induced by the β-AR agonist isoprenaline in guinea pig myocardial membranes with a Ki value of 2.4 nM.2 Penbutolol reduces basal renin activity and blood pressure in spontaneously hypertonic rats.3 It decreases isolation-induced aggressive behavior in mice (ED50 = 56 ?mol/kg) and reverses reductions in aggression induced by 8-hydroxy-DPAT and TFMPP with ED50 values of 8.1 and 2.1 ?mol/kg, respectively.1 Formulations containing penbutolol were previously used in the treatment of arterial hypertension.
1.Sánchez, C., Arnt, J., and Moltzen, E.K.The antiaggressive potency of (–)-penbutolol involves both 5-HT1A and 5-HT1B receptors and β-adrenoceptorsEur. J. Pharmacol.297(1-2)1-8(1996) 2.Krawietz, W., Poppert, D., Erdmann, E., et al.β-adrenergic receptors in guinea-pig myocardial tissueNaunyn Schmiedebergs Arch. Pharmacol.295(3)215-224(1976) 3.Kaiser, J., H?rtfelder, G., Lindner, E., et al.Pharmacology of the β-receptor blocker penbutololArzneimittelforschung30(3)420-427(1980)