Characterization of anti-peptide antibodies directed against an extracellular immunogenic epitope on the human alpha 1-adrenergic receptor.
A synthetic peptide corresponding to amino acids 192-218 of the second extracellular loop of the human alpha 1A-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 alpha 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 alpha 1-adrenergic receptor in the heart. They also confirm that the second extracellular loop of the alpha 1-adrenergic receptors is an immunologically and functionally important domain.
Fu
M L
ML
Wallenberg Laboratory, Sahlgren's Hospital, University of Göteborg, Sweden.
Wallukat
G
G
Hjalmarson
A
A
Hoebeke
J
J
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000302:isolation & purification; D002478:Cells, Cultured; D006224:Cricetinae; D000939:Epitopes / Q000737:chemistry / Q000235:genetics; D006339:Heart Rate / Q000276:immunology; D006801:Humans; D007120:Immunochemistry; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D009206:Myocardium / Q000276:immunology / Q000378:metabolism; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000235:genetics / Q000276:immunology; D011487:Protein Conformation; D011817:Rabbits; D051381:Rats; D018340:Receptors, Adrenergic, alpha-1 / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
D000906:Antibodies; D000939:Epitopes; D008565:Membrane Proteins; D010446:Peptide Fragments; D018340:Receptors, Adrenergic, alpha-1