Serotonergic current responses of neurons in rat oculomotor neural integrators
Serotonergic current responses of neurons in rat oculomotor neural integrators
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大鼠动眼神经积分神经元的血清素能电流反应
DOI：
10.1152/jn.00452.2022
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发表时间：
2023
影响因子：
2.5
通讯作者：
Sugimura Taketoshi
中科院分区：
文献类型：
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作者：
Saito Yasuhiko;Sugimura Taketoshi
舌下前核（PHN）和卡哈尔间质核（INC）分别参与控制水平和垂直凝视。先前的研究表明，PHN 神经元对血清素（5-羟色胺，5-HT）表现出去极化或超极化反应。然而，尚未检查 INC 神经元的血清素调节。此外，5-HT 诱导的反应与基于神经递质表型的神经元类型之间的关系尚未阐明。在这项研究中，我们使用野生型和转基因大鼠脑干切片的全细胞记录，研究了 PHN 和 INC 神经元中 5-HT 诱导的电流反应以及不同神经元类型中不同电流反应的分布。将 5-HT 局部应用于细胞体证实了缓慢向内 (SI) 和缓慢向外 (SO) 电流分别由 5-HT2 和 5-HT1A 受体介导。此外，还观察到由 5-HT3 受体介导的快速内向 (FI) 电流。在 PHN 和 INC 神经元中都观察到了这三种电流反应。对三种电流反应分布的分析表明，PHN 中荧光识别的谷氨酸能和抑制性神经元分别显示高比例的 SI 和 SO 电流，而 INC 中的谷氨酸能和抑制性神经元主要显示 SO 电流。当 PHN 和 INC 神经元根据放电模式进行表征时，电流的比例取决于放电模式。 5-HT 诱导电流的不同分布表明水平和垂直凝视控制特有不同的血清素调节模式。新的和值得注意的垂直凝视控制（卡哈尔间质核，INC）的血清素调节比水平凝视控制（舌下舌前核，PHN）的血清素调节了解较少。在这里，除了之前报道的缓慢的内向和外向电流之外，我们还报告了 5-HT 诱导的快速内向电流。 INC 神经元中基于神经递质表型的电流分布与 PHN 神经元中的电流分布不同。这些结果表明水平和垂直凝视控制中心存在不同的血清素调节模式。
The prepositus hypoglossi nucleus (PHN) and the interstitial nucleus of Cajal (INC) are involved in controlling horizontal and vertical gaze, respectively. Previous studies have shown that PHN neurons exhibit depolarized or hyperpolarized responses to serotonin (5-hydroxytryptamine, 5-HT). However, serotonergic modulation of INC neurons has not been examined. Furthermore, the relationship between 5-HT-induced responses and neuron types based on neurotransmitter phenotypes has not been clarified. In this study, we investigated 5-HT-induced current responses in PHN and INC neurons and the distributions of distinct current responses in different neuron types, using whole cell recordings of wild-type and transgenic rat brain stem slices. Local application of 5-HT to the cell soma confirmed that slow inward (SI) and slow outward (SO) currents were mediated by 5-HT2and 5-HT1Areceptors, respectively. Furthermore, fast inward (FI) currents that were mediated by 5-HT3receptors were observed. These three current responses were observed in both PHN and INC neurons. Analyses of the distributions of the three current responses revealed that fluorescently identified glutamatergic and inhibitory neurons in the PHN showed high proportions of SI and SO currents, respectively, whereas glutamatergic and inhibitory neurons in the INC showed mainly SO currents. When PHN and INC neurons were characterized on the basis of firing patterns, the proportions of the currents depended on the firing patterns. The different distributions of 5-HT-induced currents suggest distinct serotonergic modulation modes specific to horizontal and vertical gaze control.NEW & NOTEWORTHYSerotonergic modulation of vertical gaze control (interstitial nucleus of Cajal, INC) is less understood than that of horizontal gaze control (prepositus hypoglossal nucleus, PHN). Here, we report 5-HT-induced fast inward currents in addition to the previously reported slow inward and outward currents. The distributions of these currents in INC neurons based on neurotransmitter phenotypes differ from those in PHN neurons. These results suggest distinct serotonergic modulation modes in horizontal and vertical gaze control centers.