The prepositus hypoglossi nucleus (PHN) and the interstitial nucleus of Cajal (INC) are oculomotor neural integrators involved in the control of horizontal and vertical gaze, respectively. We previously reported that local application of adenosine 5'-trisphosphate (ATP) to PHN neurons induced P2X receptor-mediated fast inward currents, P2Y receptor-mediated slow inward currents, and/or adenosine P1 receptor-mediated slow outward currents. In contrast to the findings on PHN neurons, the expression of functional purinergic receptors in INC neurons has not been examined. In this study, we investigated ATP-induced current responses in INC neurons and the distributions of the three current types across distinct firing patterns in PHN and INC neurons using whole-cell recordings of rat brainstem slices. The application of ATP induced all three current types in INC neurons. Pharmacological analyses indicated that the fast inward and slow outward currents were mainly mediated by the P2X and P1 subtypes, respectively, corresponding to the receptor subtypes in PHN neurons. However, agonists of the P2Y subtype did not induce the slow inward current in INC neurons, suggesting that other subtypes or mechanisms are responsible for this current. Analysis of the distribution of the three current types in PHN and INC neurons revealed that the proportions of the currents were distinctly dependent on the firing patterns of PHN neurons whereas the proportion of the fast inward current was higher during all firing patterns of INC neurons. The different distributions of ATP-induced currents suggest distinct modes of purinergic modulation specific to horizontal and vertical integrators.

中文翻译：

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以不同放电模式为特征的大鼠动眼神经元的不同嘌呤能受体介导的电流

前舌下核 (PHN) 和 Cajal 间质核 (INC) 是动眼神经整合器，分别参与控制水平和垂直凝视。我们以前曾报道，将 5'-三磷酸腺苷 (ATP) 局部应用到 PHN 神经元可诱导 P2X 受体介导的快速内向电流、P2Y 受体介导的缓慢内向电流和/或腺苷 P1 受体介导的慢速外向电流。与对 PHN 神经元的发现相反，尚未检查 INC 神经元中功能性嘌呤能受体的表达。在这项研究中，我们使用大鼠脑干切片的全细胞记录研究了 ATP 诱导的 INC 神经元中的电流反应以及三种电流类型在 PHN 和 INC 神经元中不同放电模式中的分布。ATP 的应用在 INC 神经元中诱导了所有三种电流类型。药理分析表明，快速向内和缓慢向外的电流主要由 P2X 和 P1 亚型介导，分别对应于 PHN 神经元中的受体亚型。然而，P2Y 亚型的激动剂不会在 INC 神经元中诱导缓慢的内向电流，这表明其他亚型或机制是造成这种电流的原因。对 PHN 和 INC 神经元中三种电流类型分布的分析表明，电流的比例明显取决于 PHN 神经元的放电模式，而在所有 INC 神经元的放电模式中，快速内向电流的比例较高。