Description_x000D_ Application_x000D_ P1,P5-Di(adenosine-5′) pentaphosphate trilithium salt has been used as a adenylate kinase inhibitor and as a component of pre-AMPPNP rigor solution for treating muscle fibres._x000D_ Packaging_x000D_ 10, 50 mg in poly bottle_x000D_ Biochem/physiol Actions_x000D_ A diadenosine polyphosphate stored in secretory granules of thrombocytes, chromaffin and neuronal cells. After release into the extracellular space, it affects a variety of biological activities in a wide range of target tissues. In the nervous system it acts through various purinergic receptors. It also activates 5′-nucleotidase and inhibits adenosine kinase activity in vitro. Ap5A is metabolized by soluble enzymes in the blood plasma and by membrane-bound ectoenzymes of a number of cell types including endothelial and smooth muscle cells. In cardiac muscle, pM to nM concentrations significantly increase the open-probability of ryanodine-receptor (RyR2) gates, with prolonged action due to slow dissociation from the receptor.