Axonal projections of pulmonary slowly adapting receptor relay neurons in the rat
Axonal projections of pulmonary slowly adapting receptor relay neurons in the rat
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DOI：
10.1002/cne.10185
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发表时间：
2002-04-22
影响因子：
2.5
通讯作者：
Otake, K
中科院分区：
文献类型：
--
作者：
Ezure, K;Tanaka, I;Otake, K
我们阐明了二级中继神经元（P-细胞）的传出投射激活的传入起源于慢适应肺受体（SAR），以确定SAR诱发的反射的中枢通路。特别注意观察孤束核（NTS）内的P细胞投射，这可能对应于从P细胞到快速适应肺受体的二级中继神经元（RAR细胞）的抑制通路。记录戊巴比妥麻醉、麻痹和人工通气大鼠NTS的P细胞。首先，我们使用的电生理方法的逆向映射，并表明大多数的P-细胞检查投射其轴突的尾侧NTS和背外侧脑桥对应的臂旁复合体。第二，将HRP和神经生物素的混合物细胞内或跨膜注射到P细胞中。(1)染色的P细胞（n = 7）位于孤束的外侧，并且具有典型地沿着孤束的外侧边缘延伸的树突。(2)所有的P-细胞的干轴突投射到同侧髓质。其中，5个P细胞的轴突投射到疑核及其附近，并有分布的终扣。其中一些轴突在延髓腹外侧区进一步上行，并在疑核腹侧或腹外侧区分布终扣。(3)所有的P细胞都有轴突分支，在NTS区有终扣。特别是，来自三个P细胞的轴突向两侧投射到奥贝尾部的内侧NTS，即，到RAR细胞的区域。这些结果显示了涉及RAR细胞的P细胞抑制以及SAR诱导的呼吸反射的连接的解剖学基质。J. Comp.神经元446：81-94，2002. (C)2002 Wiley-Liss，Inc.
We elucidated efferent projections of second-order relay neurons (P-cells) activated by afferents originating from slowly adapting pulmonary receptors (SARs) to determine the central pathway of the SAR-evoked reflexes. Special attention was paid to visualizing the P-cell projections within the nucleus tractus solitarii (NTS), which may correspond to the inhibitory pathway from P-cells to second-order relay neurons (RAR-cells) of rapidly adapting pulmonary receptors. P-cells were recorded from the NTS in Nembutal-anesthetized, paralyzed, and artificially ventilated rats. First, we used electrophysiological methods of antidromic mapping and showed that the majority of the P-cells examined projected their axons to the caudal NTS and to the dorsolateral pons corresponding to the parabrachial complex. Second, a mixture of HRP and Neurobiotin was injected intracellularly or juxtramembranously into P-cells. (1) Stained P-cells (n = 7) were located laterally to the solitary tract and had dendrites extending characteristically along the lateral border of the solitary tract. (2) All P-cells had stem axons projecting to the ipsilateral medulla. Of these, the axons from five P-cells projected to the nucleus ambiguus and its vicinity with distributing boutons. Some of these axons further ascended in the ventrolateral medulla, and distributed boutons in the areas ventral or ventrolateral to the nucleus ambiguus. (3) All the P-cells had axonal branches with boutons in the NTS area. In particular, axons from three P-cells projected bilaterally to the medial NTS caudal to the obex, i.e., to the area of RAR-cells. These results show anatomic substrates for the connections implicated in the P-cell inhibition of RAR-cells as well as the SAR-induced respiratory reflexes. J. Comp. Neurol. 446:81-94, 2002. (C) 2002 Wiley-Liss, Inc.