Extrasynaptic release of dopamine in a retinal neuron: Activity dependence and transmitter modulation
Extrasynaptic release of dopamine in a retinal neuron: Activity dependence and transmitter modulation
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DOI：
10.1016/s0896-6273(01)00274-4
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发表时间：
2001-04-01
期刊：
影响因子：
16.2
通讯作者：
Raviola, E
中科院分区：
文献类型：
--
作者：
Puopolo, M;Hochstetler, SE;Raviola, E
突触外多巴胺的释放是有据可查的，但其与神经元生理活动的关系尚不清楚。在这里，我们表明，在突触前活动区的情况下，视网膜多巴胺能神经元的孤立细胞体通过胞吐作用以不规则的间隔和低频率释放类似于40，000个多巴胺分子的包。这种释放是由神经元在去除所有突触影响后以有节奏的方式产生的动作电位触发的，因此取决于神经元表面的电事件。此外，它被红藻氨酸刺激，并被GABA和喹吡罗（D-2多巴胺受体的激动剂）消除。由于这些配体的体细胞受体是突触外的，我们认为细胞外液的组成直接调节突触外释放。
Extrasynaptic release of dopamine is well documented, but its relation to the physiological activity of the neuron is unclear. Here we show that in absence of presynaptic active zones, solitary cell bodies of retinal dopaminergic neurons release by exocytosis packets of similar to 40,000 molecules of dopamine at irregular intervals and low frequency. The release is triggered by the action potentials that the neurons generate in a rhythmic fashion upon removal of all synaptic influences and therefore depends upon the electrical events at the neuronal surface. Furthermore, it is stimulated by kainate and abolished by GABA and quinpirole, an agonist at the D-2 dopamine receptor. Since the somatic receptors for these ligands are extrasynaptic, we suggest that the composition of the extracellular fluid directly modulates extrasynaptic release.