A COMPARATIVE STUDY OF β‐ADRENOCEPTORS IN HUMAN AND PORCINE LUNG PARENCHYMA STRIP

Abstract

1 Responses to (±)-isoprenaline (Iso), (−)-adrenaline (Adr) and (−)-noradrenaline (NA) were compared in isolated preparations of human and porcine lung parenchyma strip. 2 The order of relaxant potencies of these catecholamines in both human and porcine lung parenchyma was Iso > Adr > NA (1:0.24:0.01, human; 1:0.21:0.01, pig). These results suggest that β₂-adrenoceptors predominate in both types of lung parenchyma strip. 3 pA₂ values for the β-adrenoceptor antagonist, propranolol (non-selective), with Iso as the agonist, in human and porcine lung strips were 7.84 and 7.83 respectively and for atenolol were 6.50 and 5.35 respectively. Taken as a whole, results indicate the existence of an apparently homogeneous population of β₂-adrenoceptors in porcine parenchyma strip, while both β₁ and β₂-adrenoceptors were revealed in human lung parenchyma.