Alprenolol (Alpheprol) is a non-selective β-adrenergic receptor (β-AR) antagonist that is also an antagonist of the serotonin (5-HT) receptor subtypes 5-HT1A and 5-HT1B.

Alprenolol binds to β1-, β2-, and β3-ARs expressed in CHO cells (Kds = 15, 0.91, and 117 nM, respectively, for the human receptors) and to 5-HT1A and 5-HT1B receptors in rat hippocampal and striatal membranes (Kis = 34 and 134 nM, respectively) [1,2].

In vivo, alprenolol (40 mg/kg, i.v.) completely blocks the hyperactivity response of rats to 2-PCPA (Item No. 10010494) and L-tryptophan [3]. Alprenolol (10 μg, i.v.) inhibits decreases in heart rate and left ventricular systolic pressure induced by the β2-AR antagonist ICI 118551 in transgenic mice overexpressing the β2-AR [4]. It also reduces the level of abnormal prion fibrils (PrPSc) in the brain of mice intracerebrally infected with prion disease to less than 20% of control levels when administered in drinking water at a dose of 50 mg/L [5].