title: Different sensitivity of alpha 2A-C10 and alpha 2C-C4 receptor subtypes in coupling to inhibition of cAMP accumulation.
abstract: Two human alpha 2-adrenergic receptor subtypes, alpha 2A-C10 and alpha 2C-C4, were compared with respect to their ability to inhibit stimulated cAMP-production. The inhibition was transduced with about one order of magnitude higher sensitivity in the alpha 2C-C4 subtype than in the alpha 2A-C10 subtype. The phorbol ester, TPA, known to desensitize alpha 2-adrenergic receptor function, possible through phosphorylation of Gi, almost completely abolished the inhibition of cAMP-production in the alpha 2C-C4 subtype, while only a partial effect was seen in the alpha 2A-C10 subtype. These results suggest that the receptor subtypes differ with respect to their coupling efficiency to adenylyl cyclase.
authors.affiliation: Department of Biochemistry and Pharmacy, BioCity, Abo Akademi University, Turku, Finland.
authors.forename: C C
authors.initials: CC
authors.lastname: Jansson
authors.forename: J M
authors.initials: JM
authors.lastname: Savola
authors.forename: K E
authors.initials: KE
authors.lastname: Akerman
mesh_terms: D000225:Adenine / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D003000:Clonidine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007700:Kinetics; D020926:Medetomidine; D009638:Norepinephrine / Q000494:pharmacology; D018341:Receptors, Adrenergic, alpha-2 / Q000145:classification / Q000187:drug effects / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014162:Transfection; D015016:Yohimbine / Q000378:metabolism
chemical_list: D000317:Adrenergic alpha-Antagonists; D007093:Imidazoles; D018341:Receptors, Adrenergic, alpha-2; D005576:Colforsin; D015016:Yohimbine; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D000225:Adenine; D003000:Clonidine; D020926:Medetomidine; D013755:Tetradecanoylphorbol Acetate; D009638:Norepinephrine