Tonic dopamine induces persistent changes in the transient potassium current through translational regulation.
Tonic dopamine induces persistent changes in the transient potassium current through translational regulation.
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DOI：
10.1523/jneurosci.2194-11.2011
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发表时间：
2011-09-14
期刊：
影响因子：
--
通讯作者：
Baro DJ
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文献类型：
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作者：
Rodgers EW;Krenz WD;Baro DJ
神经调节作用可因其传播方式而异。相释放产生局部和短暂的增加多巴胺（DA）高达微摩尔浓度。此外，由于DA从开放的突触释放，再摄取机制不在附近，强直性纳摩尔DA存在于细胞外空间。在给定的神经元中，相位传输和张力传输是否类似地调节依赖电压的离子电导？先前的研究表明，DA可以立即改变刺龙虾口胃神经节（STG）中特定神经元的瞬态钾电流（IA）。在这里，我们表明DA也可以持续地改变IA，并且DA的即时和持久影响是相互对立的。幽门外侧神经元（LP）只表达1型DA受体（D1Rs）。微摩尔DA在低电压IA的电压依赖性中产生立即的去极化位移，而tonic纳摩尔DA通过涉及雷帕霉素靶点（TOR）的翻译依赖机制产生低电压IA最大电导（Gmax）的持续增加。幽门扩张神经元（PD）只表达2型DA受体（D2Rs）。微摩尔DA在PD - IA电压依赖性激活中产生立即的超极化位移，而强直DA通过不涉及TOR的翻译依赖性机制持续降低PD - IA Gmax。对IA Gmax的持续影响不依赖于LP或PD活性。这些数据表明，强直调制器在调节电压门控离子通道数中的作用；此外，多巴胺能系统可能会被组织起来限制它们施加在回路上的变化量。
Neuromodulatory effects can vary with their mode of transmission. Phasic release produces local and transient increases in dopamine (DA) up to micromolar concentrations. Additionally, since DA is released from open synapses and reuptake mechanisms are not nearby, tonic nanomolar DA exists in the extracellular space. Do phasic and tonic transmissions similarly regulate voltage dependent ionic conductances in a given neuron? It was previously shown that DA could immediately alter the transient potassium current (IA) of identified neurons in the stomatogastric ganglion (STG) of the spiny lobster, Panulirus interruptus. Here we show that DA can also persistently alter IA, and that DA’s immediate and persistent effects oppose one another. The lateral pyloric neuron (LP) exclusively expresses type 1 DA receptors (D1Rs). Micromolar DA produces immediate depolarizing shifts in the voltage dependence of LP IA, whereas tonic nanomolar DA produces a persistent increase in LP IA maximal conductance (Gmax) through a translation dependent mechanism involving target of rapamycin (TOR). The pyloric dilator neuron (PD) exclusively expresses type 2 DA receptors (D2Rs). Micromolar DA produces an immediate hyperpolarizing shift in PD IA voltage dependence of activation, whereas tonic DA persistently decreases PD IA Gmax through a translation dependent mechanism not involving TOR. The persistent effects on IA Gmax do not depend on LP or PD activity. These data suggest a role for tonic modulators in the regulation of voltage gated ion channel number; and furthermore, that dopaminergic systems may be organized to limit the amount of change they can impose on a circuit.