In order to investigate the cardioselective effects of new β-blocker acebutolol, cardio-pulmonary functions were studied with normal and bronchial asthmatics. In normal subjects, heart rates reduced after intravenous injections of propranolol and acebutolol, however, no significant changes were observed in Rr, Raw, VC, FEV_1, CV, and FV curves. Acebutolol, was injected intravenously after inhalation of metaproterenol to 15 asthmatics on remission and to 10 asthmatics with mild attack. In both groups, tachycardia induced after inhalation of metaproterenol was blocked by acebutolol. After inhalation of metaproterenol, VC, FEV_1, and flow on FV curves increased and Rr decreased significantly. After acebutolol injection, slight reduction of PF and elevation of Rr were observed, however, these values remained better than those of control. V_<50> and V_<25> improved after metaproterenol and were not affected by acebutolol. These results suggest that acebutolol may cause constriction to the central airways but only in slight degree. The results show that acebutolol would be a cardioselective β blocker.
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