Premium
α 1 ‐Adrenoceptor function and autoradiographic distribution in human asthmatic lung
Author(s) -
Spina Dom,
Rigby Paul J.,
Paterson James W.,
Goldie Roy G.
Publication year - 1989
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1989.tb12006.x
Subject(s) - prazosin , phenylephrine , dissociation constant , bronchus , lung , endocrinology , medicine , binding site , adrenergic receptor , distribution (mathematics) , biology , receptor , chemistry , respiratory disease , biochemistry , antagonist , blood pressure , mathematical analysis , mathematics
1 The autoradiographic distribution of α 1 ‐adrenoceptors was investigated in non‐diseased and asthmatic human lung by use of [ 3 H]‐prazosin (H‐PZ). To validate binding and autoradiographic methods, H‐PZ binding was also measured in rat heart. 2 Significant levels of specific H‐PZ binding were detected in sections of rat heart. This binding was associated with a single class of non‐interacting sites of high affinity (dissociation constant, K d = 1.17 ± 0.26 n m ). The maximum binding capacity ( B max ) was 59.5 ± 4.5 fmol mg −1 protein. 3 In sharp contrast, very low levels of specific H‐PZ binding were found in both human non‐diseased and asthmatic bronchus, although a high level of binding of [ 125 I]‐iodocyanopindolol (I‐CYP, 50 p m ) to β‐adrenoceptors was detected in these airways. Furthermore, very low levels of autoradiographic grains representing specific H‐PZ binding were found in all airway structures in human non‐diseased or asthmatic lung parenchyma. 4 Consistent with these data, the α‐adrenoceptor agonist phenylephrine failed to induce significant increases in tone in bronchi isolated from either non‐diseased or asthmatic human lung. Results indicate that asthma does not involve significant increases in airway α 1 ‐adrenoceptor function.