Open AccessCharacterization of anti‐peptide antibodies directed against an extracellular immunogenic epitope on the human α 1 ‐adrenergic receptor
Author(s) -
FU M. L. X.,
WALLUKAT G.,
HJALMARSON A.,
HOEBEKE J.
Publication year - 1994
Publication title -
clinical & experimental immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.329
H-Index - 135
eISSN - 1365-2249
pISSN - 0009-9104
DOI - 10.1111/j.1365-2249.1994.tb06593.x
Subject(s) - receptor , extracellular , antibody , epitope , agonist , biology , peptide , prazosin , chronotropic , microbiology and biotechnology , biochemistry , chemistry , endocrinology , antagonist , immunology , heart rate , blood pressure
SUMMARY A synthetic peptide corresponding to amino acids 192–218 of the second extracellular loop of the human α IA ‐adrenergic receptor was used to raise antibodies in rabbits, Affinity‐purified antibodies specifically recognized main bands with a molecular weight of about 68, 40 and 37 kD on the electrotransferred membrane proteins of rat ventricle membranes. The incubation of these antibodies with rat myocardial membranes resulted in a decrease in the number of binding sites for the specific radiolabelled α 1 ‐antagonist prazosin. These antibodies were also able to mimic the effects of agonist stimulation as demonstrated by a positive chronotropic effect on cultured cardiomyocytes. These results constitute the first immunochemical evidence of the presence of both the A and B subtypes of the α 1 ‐adrenergic receptor in the heart. They also confirm that the second extracellular loop of the α 1 ‐adrenergic receptors is an immunologically and functionally important domain.