P2Y12 nucleotide receptor antagonists, including clopidogrel, for the treatment of stroke

T purinergic hypothesis (i.e. ATP as an extracellular signalling molecule) was proposed in 1972. In the early 1990’s, receptors for ATP were cloned and characterised, consisting of two families: P2X ion channel receptors (7 subtypes) and P2Y G protein-coupled receptors (8 subtypes). P2Y1 and P2Y12 receptors were identified on platelets, mediating their aggregation. Clopidogrel, whose breakdown product is a P2Y12 receptor antagonist was identified for the treatment of thrombosis and stroke and has been widely used,more recently, directly acting P2Y12 receptor antagonists such as Ticagrelor have been introduced, the relative merits of various P2Y12 receptor antagonists for the treatment of stroke will be discussed.