Assessment of adrenergic beta-blockade in the anesthetized rat at different baseline values

The influence of different baseline values (blood pressure, heart rate) on ED50- and Emax-values of isoprenaline dose-response curves (DRC) in the presence and absence of beta-blocking drugs was assessed in urethane-anesthetized rats. The results show that Urethane is a suitable anesthetic in this animal model. Different baselines have no influence in ED50-values. Assessment of potency of competitive antagonists (pA2) from complete DRC appears unaffected by differences in baseline or in Emax. Pharmacologic effects (heart rate, blood pressure) are better depicted as absolute effect values than delta-values.