In this review we will discuss the effect of two neuromodulatory transmitters, acetylcholine (ACh) and adenosine, on the synaptic release probability and short-term synaptic plasticity. ACh and adenosine differ fundamentally in the way they are released into the extracellular space. ACh is released mostly from synaptic terminals and axonal bouton of cholinergic neurons in the basal forebrain. Its mode of action on synaptic release probability is complex because it activate both ligand-gated ion channels, so-called nicotinic ACh receptors and G-protein coupled muscarinic ACh receptors. In contrast, adenosine is released from both neurons and glia via nucleoside transporters or diffusion over the cell membrane in a non-vesicular, non-synaptic fashion; its receptors are exclusively G-protein coupled receptors. We show that ACh and adenosine effects are highly specific for an identified synaptic connection and depend mostly on the presynaptic but also on the postsynaptic receptor type and discuss the functional implications of these differences.

在这篇综述中，我们将讨论两种神经调节递质，乙酰胆碱（ACh）和腺苷对突触释放概率和短期突触可塑性的影响。ACh和腺苷在释放到细胞外空间的方式上根本不同。ACh主要从基底前脑的突触末梢和胆碱能神经元的轴突bouton释放。它对突触释放可能性的作用方式很复杂，因为它既激活配体门控离子通道，又激活所谓的烟碱ACh受体和G蛋白偶联毒蕈碱ACh受体。相反，腺苷通过核苷转运蛋白从神经元和神经胶质中释放出来，或者以非囊泡，非突触的方式在细胞膜上扩散。其受体仅是G蛋白偶联受体。