Presynaptic modulation of the release of the co‐transmitters noradrenaline and ATP

摘要

Summary—The release of both sympathetic co‐transmitters, noradrenaline and ATP, is modulatedviapresynaptic receptors. However, the degree of the modulation may differ indicating that the ratio of the released co‐transmitters changes upon presynaptic receptor activation. For example, α2‐autoinhibition affects the release of noradrenaline more markedly than the release of ATP. Some sympathetic axon terminals possess presynaptic P2‐purinoceptors which are activated by endogenous ATP. These receptors are a novel kind of auto‐receptor: they mediate a presynaptic negative feedback mechanism in which released ATP inhibits subsequent co‐trans