Sun Q J, Minson J, Llewellyn-Smith I J, Arnolda L, Chalmers J, Pilowsky P
Department of Neurosurgery, Royal North Shore Hospital, St. Leonards, NSW, Australia.
J Comp Neurol. 1997 Nov 10;388(1):23-31. doi: 10.1002/(sici)1096-9861(19971110)388:1<23::aid-cne2>3.0.co;2-q.
Sympathetic nerve activity often fluctuates with the respiratory cycle, but the central neurons that impose this respiratory modulation have not been conclusively identified. In the present study, we used intracellular recording and dye-filling to identify expiratory neurons in the Bötzinger complex. Our aim was to see if Bötzinger neurons project towards putative cardiovascular neurons in the rostral ventrolateral medulla. In the first series of experiments, histochemistry and immunohistochemistry were used to reveal the labelled Bötzinger neurons and neurons immunoreactive for tyrosine hydroxylase. Two out of four Bötzinger neurons had axon varicosities that were closely apposed to tyrosine hydroxylase-immunoreactive neurons with cell bodies located within 0.6 mm caudal to the facial nucleus (three and five close appositions, respectively). In a second series of studies, rats were injected with cholera toxin B into the intermediolateral cell column of the spinal cord 4-7 days before the electrophysiological recording. Eight of the fourteen labelled Bötzinger neurons had a direct projection towards cholera toxin B-labelled neurons in the rostral ventrolateral medulla. Close appositions were found on both somata and proximal dendrites (5 +/- 2 close appositions/neuron, n = 8). The present study supports the idea that a direct projection from Bötzinger neurons to presympathetic neurons in the rostral medulla plays a role in the respiratory modulation of sympathetic nerve activity.
交感神经活动常随呼吸周期波动，但施加这种呼吸调制的中枢神经元尚未得到最终确认。在本研究中，我们采用细胞内记录和染料填充法来识别包钦格复合体中的呼气神经元。我们的目的是探究包钦格神经元是否投射至延髓头端腹外侧的假定心血管神经元。在第一组实验中，运用组织化学和免疫组织化学方法来揭示标记的包钦格神经元以及对酪氨酸羟化酶呈免疫反应的神经元。四个包钦格神经元中有两个具有轴突膨体，它们与位于面神经核尾侧0.6毫米范围内、胞体对酪氨酸羟化酶呈免疫反应的神经元紧密相邻（分别有三个和五个紧密相邻）。在第二组研究中，在电生理记录前4 - 7天，将霍乱毒素B注射到大鼠脊髓的中间外侧细胞柱中。14个标记的包钦格神经元中有8个直接投射至延髓头端腹外侧中霍乱毒素B标记的神经元。在胞体和近端树突上均发现了紧密相邻的情况（每个神经元有5±2个紧密相邻，n = 8）。本研究支持这样一种观点，即从包钦格神经元到延髓头端的交感神经节前神经元存在直接投射，并在交感神经活动的呼吸调制中发挥作用。
