Functional role of the ATP receptor-mediated signaling in the solitary network

在孤立复合体中，细胞外atp介导的信号传导在中枢心肺网络中的功能作用已被澄清，其中P2X （atp门控的非特异性阳离子通道）的丰富表达已被组织化学证实。在10 ~ 30日龄大鼠脑干厚片上，用红外视频显微镜观察神经元的全细胞电流。得出了以下结论：atp介导的突触传递从孤立束（TS）到孤立束核（NTS）二级神经元的突触参与似乎很少。我未能在TS刺激诱发的突触后电流（PSC）中检测到对CNQX、AP5、双曲碱和士的宁耐药的成分。此外，与使用新分离的NTS细胞所证明的相反，没有NTS神经元显示ATP向内电流（n=10）.2。然而，ATP及其类似物通过TS刺激二级NTS神经元修饰PSCs，这表明P2X受体参与了传入信息输入增益的突触前调节。迷走神经背运动核（dmnX）约70%的大直径（b> * 30mum）神经元显示atp诱导的抗ttx向内电流并伴有爆发样psc。双库兰消除了贴片液中cscs的大部分记录，表明这些PSCs主要是gaba能和部分谷氨酰胺能的PSCs。ATP激活的PSCs被TTX破坏。这是一个新的发现，表明除了副交感神经节前细胞外，向这些细胞发送突触连接的gaba能和谷氨酰胺能前运动神经元也表达P2X受体。

It was attempted to clarify the functional role of extracellular ATP-mediated signaling in the central cardiorespiratory network in the solitary complex in which abundant expression of P2X (ATP-gated non-specific cation channels) has been demonstrated histochemically. The whole-cell current was recorded from neurons visually identified with infra-red videomicroscopy in the thick brainstem slice of rats (10-30 days old). The following conclusions were drawn.1. Involvement of ATP-mediated synaptic transmission in the synapse from solitary tract (TS) to second-order neurons in the nucleus of the solitary tract (NTS) seems to be little. I failed to detect component resistant to CNQX, AP5, bicuculline and strychnine in the TS stimulation-evoked post-synaptic current (PSC). In addition, on contrary to those demonstrated using freshly dissociated NTS cells, no NTS neuron showed inward current with ATP (n=10).2. However, ATP and its analogues modified PSCs evoked by TS stimulation of the second-order NTS neurons, indicating that P2X receptors are involved in presynaptic regulation of the input gain of afferent information.3. About 70% of the large diameter (>*30 mum) neurons in dorsal motor nucleus of vagus (dmnX) showed ATP-induced TTX-resistant inward currents together with burst-like PSCs. Bicuculline abolished most of Recording with CsCl in the patch solution indicated that these are mainly GABAergic and partly glutaminergic PSCs. The PSCs activated by ATP was abolished with TTX.This is a novel finding indicating that, in addition to the parasympathetic preganglionic cells, the GABAergic and glutaminergic premotor neurons sending synaptic connections to these cells also express P2X receptors.