Many neuronal and non-neuronal cell types release ATP in a controlled manner. After release, extracellular ATP (or, following hydrolysis, ADP) acts on cells in a paracrine manner via P2 receptors. Extracellular nucleotides are now thought to play an important role in the regulation of bone cell function. ATP (and ADP), acting via the P2Y(1) receptor, stimulate osteoclast formation and activity,...

Growing evidence indicates that ATP may play a very important role in Long-Term Potentiation (LTP), a neurophysiological process that has been implicated in memory formation. LTP is an enhancement of synaptic strength induced by a specific pattern of high frequency stimulation, or by application of exogenous ATP. In the hippocampus LTP-inducing stimulation is accompanied by a massive, Ca(2+)-de...

The recombinant rat P2X(5) (rP2X(5)) receptor, a poorly understood ATP-gated ion channel, was studied under voltage-clamp conditions and compared with the better understood homomeric rP2X(1) receptor with which it may coexist in vivo. Expressed in defolliculated Xenopus laevis oocytes, rP2X(5) responded to ATP with slowly desensitizing inward currents that, for successive responses, ran down in...