The beta-adrenoceptors of lymphocytes in asthmatic patients treated with beta-agonists

Numbers of beta-adrenoceptors in intact human lymphocytes of asthmatics treated continuously with the usual doses of beta-agonists have been estimated. Lymphocytes were isolated by density gradient centrifugation as described by BOYUM [4]. The binding experiment was performed with (-)3H-dihydroalprenolol which is a high affinity beta-adrenoceptor antagonist. There was no difference between the mean values of the binding sites of asthmatic patients and those of the normal volunteers. In asthmatic patients, a significant correlation was found between the density of receptors and the percentage increase of FEV1 after salbutamol inhalation. Symptoms of drug tolerance were not observed in patients treated with therapeutic doses of beta-agonists.