A study of beta-adrenoceptors in rat lung parenchymal strip.
The aim of the present study was to characterize the beta-adrenoceptor population in rat lung strip. For this purpose, Schild plots were obtained for the beta-adrenoceptor antagonists atenolol (beta 1-selective), butoxamine (beta 2-selective) and propranolol (non-selective), using three different agonists:isoprenaline (non-selective), salbutamol (beta 2-selective) and noradrenaline (beta 1-selective). The slopes of these Schild plots were close to the theoretical value of unity, and pA2 values determined with isoprenaline, salbutamol and noradrenaline as agonists were: for propranolol, 7.86 +/- 0.22, 7.72 +/- 0.15 and 7.89 +/- 0.23; for atenolol, 5.19 +/- 0.05, 5.33 +/- 0.07 and 5.47 +/- 0.22 and for butoxamine, 6.31 +/- 0.11, 6.34 +/- 0.03 and 5.99 +/- 0.23, respectively. These data suggest that pharmacological responses of rat isolated lung strip to beta-adrenoceptor agents are mediated by a homogeneous population of beta 2-adrenoceptors, although the presence of a minor population of beta 1-adrenoceptors undetected by the agonists used cannot be excluded.
Candenas
M L
ML
Departamento de Farmacologia y Farmacotecnia, Facultad de Farmacia, Valencia, Spain.
Anselmi
E
E
D000420:Albuterol / Q000494:pharmacology; D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D002078:Butoxamine / Q000494:pharmacology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008168:Lung / Q000378:metabolism*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*
D011943:Receptors, Adrenergic, beta; D002078:Butoxamine; D001262:Atenolol; D011433:Propranolol; D007545:Isoproterenol; D000420:Albuterol; D009638:Norepinephrine