Selective blockade of β-adrenoceptors by 1-(p-allylphenoxy)-3-isopropylamino-2 propanol hydrochloride (H 64/52) in the anaesthetized dog

摘要

1. The β-adrenoceptor blocking properties of 1-(p-allylphenoxy)-3-isopropylamino-2-propanol hydrochloride (H 64/52) on the cardiovascular and bronchomotor responses to isoprenaline have been determined in the anaesthetized dog.2. H 64/52 selectively blocked the isoprenaline-induced increase in heart rate, contractile force and reduction in airway pressure in the same dose range.3. H 64/52 produced a minimal blockade of vascular β-adrenoceptors which was apparent only when the isoprenaline-induced fall in diastolic pressure was considered. No significant vascular β-adrenoceptor blockade with H 64/52 could be shown with the femoral arterial flow or hind-limb perfusion studies.4. These results further support the hypothesis that several different β-adrenoceptor subtypes exist in the dog. The β-adrenoceptors subserving cardiac stimulation and bronchodilation appear to be similar and both differ from the β-adrenoceptor subserving vasodilatation.