1 Purinergic signalling is involved both in short-term control of vascular tone and in longer-term control of cell proliferation, migration and death involved in vascular remodelling. 2 There is dual control of vascular tone by adenosine 5'-triphosphate (ATP) released from perivascular nerves and by ATP released from endothelial cells in response to changes in blood flow (shear stress) and hypoxia. 3 Both ATP and its breakdown product, adenosine, regulate smooth muscle and endothelial cell proliferation. 4 These regulatory mechanisms are important in pathological conditions, including hypertension, atherosclerosis, restenosis, diabetes and vascular pain.