Purine P2Y receptors in ATP-mediated regulation of non-quantal acetylcholine release from motor nerve endings of rat diaphragm

► We studied the action of ATP on non-quantal release of ACh in rat endplates. ► ATP inhibits non-quantal release of ACh via P2Y but not P2X receptors. ► Action of ATP occurs through the activation of phospholipase C. ► Action of ATP is independent of the activity of NO-synthase and Ca2+ channels. ► Mechanisms of ATP and glutamate inhibitory actions on ACh release are independent.