Alpha-1 adrenoceptor Catecholamine Alpha-1 adrenoceptor:Catecholamine Alpha-1 adrenoceptors bind catecholamines Authored: Jassal, B, 2009-02-10 10:07:58 Edited: Jassal, B, 2009-02-10 10:07:58 Pubmed1328250 Pubmed7746284 Pubmed8396931 Reactome Database ID Release 43390641 Reactome, http://www.reactome.org ReactomeREACT_16992 Reviewed: D'Eustachio, P, 2009-03-02 09:24:35 The alpha-1 adrenoceptors are involved in smooth muscle contraction. This is achieved by the receptor-ligand complex coupling with the G protein alpha-q/11 subtype, which results in increased intracellular calcium and thus muscle contraction. There are 3 subtypes of the alpha-1 adrenoceptor; 1a (Hirasawa A et al, 1993), 1b (Ramarao CS et al, 1992) and 1d (Esbenshade TA et al, 1995).