Assessment of selective β‐adrenoceptor blockade in man

Abstract

1 Selective antagonism of the cardiac β₁-adrenoceptors has been studied in normal human volunteers. 2 Practolol and UK 6558 produced greater antagonism of the chronotropic and inotropic responses to i.v. isoprenaline than of the vasodilator response to either i.v. or intra-arterial isoprenaline. A third drug, M&B 17,803A, produced non-selective β-adrenoceptor blockade in 2 of 3 subjects studied. 3 Practolol, UK 6558 and M&B 17,803A, produced an attenuation of the responses to Valsalva's manoeuvre. 4 A substantial reduction in blood pressure was seen in 3 of 4 normotensive subjects given UK 6558.