McAllen R M
J Auton Nerv Syst. 1986 Oct;17(2):151-64. doi: 10.1016/0165-1838(86)90090-1.
Experiments were performed on 21 chloralose-anaesthetized, paralyzed cats to identify electrophysiologically the bulbospinal vasomotor neurones of the rostral ventrolateral medulla. Neurones were recorded from a small region close to the ventral medullary surface (sub-retrofacial nucleus), where previous studies had localized points where microinjected excitant amino acids produced large pressor responses. A total of 157 neurones in this region were antidromically activated by electrical stimulation in the spinal cord, 132 from the ipsilateral dorsolateral funiculus at lower cervical level and 25 from the intermediolateral horn at T1. Of the cells tested, 33/34 were excited by iontophoresis of homocysteic acid, indicating that recordings originated from cell bodies rather than axons. The positions of 16 were marked by dye deposition, and located histologically to the sub-retrofacial nucleus. Stimulation of baroreceptors by inflating a carotid sinus blind sac to 200 mm Hg powerfully inhibited 41/48 bulbospinal neurones tested. The threshold for this effect was 80-100 mm Hg. Baroreceptor-sensitive neurones all had axonal conduction velocities between 2 and 8.8 m/s, and within this range, all but two cells were barosensitive. Barosensitive cells were unaffected by low threshold somatosensory stimulation. Baroreceptor stimulation was still able to silence these neurones' activity even when this was raised several-fold by iontophoresis of homocysteic acid. It is argued that sub-retrofacial bulbospinal neurones probably constitute a major descending vasomotor pathway, and that baroreceptors act by inhibiting them postsynaptically.
对21只氯醛糖麻醉、麻痹的猫进行了实验，以电生理学方法鉴定延髓头端腹外侧区的延髓脊髓血管运动神经元。在靠近延髓腹侧表面的一个小区域（面神经后核下方）记录神经元，之前的研究已在此区域定位了微量注射兴奋性氨基酸产生大升压反应的点。该区域共有157个神经元通过脊髓电刺激进行了逆向激活，其中132个来自下颈段同侧背外侧索，25个来自T1节段的中间外侧角。在所测试的细胞中，33/34个细胞通过同型半胱氨酸的离子电泳被兴奋，表明记录源自细胞体而非轴突。16个细胞的位置通过染料沉积进行了标记，并通过组织学方法定位到面神经后核下方。通过将颈动脉窦盲囊充气至200 mmHg来刺激压力感受器，强烈抑制了48个测试的延髓脊髓神经元中的41个。这种效应的阈值为80 - 100 mmHg。压力感受器敏感神经元的轴突传导速度均在2至8.8 m/s之间，在此范围内，除两个细胞外，所有细胞均对压力敏感。压力感受器敏感细胞不受低阈值体感刺激的影响。即使通过同型半胱氨酸的离子电泳使这些神经元的活动增强数倍，压力感受器刺激仍能使其活动停止。有人认为，面神经后核下方的延髓脊髓神经元可能构成主要的下行血管运动通路，压力感受器通过突触后抑制这些神经元起作用。
