title: Immunological identification of A1 adenosine receptors in brain cortex.
abstract: The A1 adenosine receptor from pig brain cortex has been identified by means of two antipeptide antibodies against two domains of the receptor molecule: PC/10 antiserum was raised against a part of the third intracellular loop, and PC/20 antiserum was raised against a part of the second extracellular loop. PC/10 antibody was able to recognize a 39-kDa band that corresponded to the A1 receptor, as demonstrated by immunoblotting and by immunoprecipitation of the molecule cross-linked to [125I](R)-2-azido-N2-p-hydroxy(phenylisopropyl)adenosine. Besides the 39-kDa band, PC/20 also recognized a 74-kDa form that does not seem to correspond to a receptor-G protein complex. The occurrence of the two bands was detected and analyzed in samples from different species and tissues showing a heterogeneous distribution of both. The 74-kDa form can be converted into the 39-kDa form by treatment with agonists or antagonists of A1 adenosine receptors. These results suggest that A1 adenosine receptor can occur in dimers and that the dimer-monomer conversion might be regulated by adenosine as the physiological ligand. Since the 74-kDa aggregates were not recognized by PC/10, it is likely that part of the third intracellular loop participates in the protein-protein interaction.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Catalunya, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Ciruela
authors.forename: V
authors.initials: V
authors.lastname: Casadó
authors.forename: J
authors.initials: J
authors.lastname: Mallol
authors.forename: E I
authors.initials: EI
authors.lastname: Canela
authors.forename: C
authors.initials: C
authors.lastname: Lluis
authors.forename: R
authors.initials: R
authors.lastname: Franco
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D011869:Radioligand Assay; D051381:Rats; D018047:Receptors, Purinergic P1 / Q000378:metabolism*; D013552:Swine
chemical_list: D018047:Receptors, Purinergic P1