Decavanadate, a P2X receptor antagonist, and its use to study ligand interactions with P2X7 receptors.
In this study we have studied decavanadate effects at P2X receptors. Decavanadate competitively blocked 2'- and 3'-O-(4benzoylbenzoyl) ATP (BzATP) stimulated ethidium accumulation in HEK293 cells expressing human recombinant P2X7 receptors (pK(B) 7.5). The effects of decavanadate were rapid (minutes) in both onset and offset and contrasted with the much slower kinetics of pyridoxal 5-phosphate (P5P), Coomassie brilliant blue (CBB) and 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine (KN62). Decavanadate competitively blocked the slowly reversible, or irreversible, blockade of the P2X7 receptor produced by P5P and oxidised ATP suggesting competition for a common binding site. However, the interaction between decavanadate and KN62 was non-competitive. Decavanadate also blocked P2X2 and P2X4 receptors but with slightly lower potency. These data demonstrate that decavanadate is the first reversible and competitive antagonist of the P2X7 receptor and is a useful tool for studying the mechanism of interaction of ligands with the P2X7 receptor.
Neurology and GI Centre of Excellence for Drug Discovery, GlaxoSmithKline Research and Development Limited, New Frontiers Science Park, Third Avenue, Harlow, Essex, CM19 5AW, UK. anton.d.michel@gsk.com
Anton D
AD
Michel
Mengle
M
Xing
Kyla M
KM
Thompson
Clare A
CA
Jones
Patrick P A
PP
Humphrey
D020013:Calcium Signaling / Q000187:drug effects; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008564:Membrane Potentials / Q000187:drug effects; D058919:Purinergic P2 Receptor Antagonists; D011732:Pyridoxal Phosphate / Q000494:pharmacology; D018048:Receptors, Purinergic P2 / Q000235:genetics; D058476:Receptors, Purinergic P2X2; D058848:Receptors, Purinergic P2X4; D058486:Receptors, Purinergic P2X7; D012394:Rosaniline Dyes / Q000494:pharmacology; D014162:Transfection; D014638:Vanadates / Q000494:pharmacology*
D008024:Ligands; C546401:P2RX2 protein, human; C548226:P2RX4 protein, human; C546468:P2RX7 protein, human; D058919:Purinergic P2 Receptor Antagonists; D018048:Receptors, Purinergic P2; D058476:Receptors, Purinergic P2X2; D058848:Receptors, Purinergic P2X4; D058486:Receptors, Purinergic P2X7; D012394:Rosaniline Dyes; D014638:Vanadates; D011732:Pyridoxal Phosphate; C004692:coomassie Brilliant Blue