(Rac)-奈必洛尔

(Rac)-Nebivolol (R-65824) is a racemic beta-blocker with β₁-adrenergic receptor antagonistic activity. In guinea pig isolated right atria, (Rac)-Nebivolol can competitively antagonize norepinephrine effects with a pKb of 7.90, and can right-shift the isoproterenol-induced tachycardia dose-response curve in conscious rabbits. (Rac)-Nebivolol has relatively high β₁ receptor binding affinity, with a racemate Ki of approximately 0.9 nM and a β₂/β₁ selectivity ratio of approximately 50; β₁ receptor blocking activity is mainly associated with the SRRR enantiomer, while the RSSS enantiomer has different vasodilation-related effects. In animal studies, (Rac)-Nebivolol can also affect epinephrine-induced catecholamine metabolism and ischemia-related myocardial metabolic changes; therefore, (Rac)-Nebivolol can be used in research on β₁ receptor pharmacology, cardiovascular regulation, myocardial ischemia, and oxidative stress.