Synaptic organization of tectal-facial pathways in cat. II. Synaptic potentials following midbrain tegmentum stimulation.
Synaptic organization of tectal-facial pathways in cat. II. Synaptic potentials following midbrain tegmentum stimulation.
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猫顶盖面部通路的突触组织。
DOI：
10.1152/jn.1990.64.2.381
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发表时间：
1990
影响因子：
2.5
通讯作者：
Baker,R
中科院分区：
文献类型：
--
作者：
May,PJ;Vidal,PP;Baker,R
1. 通过在猫身上使用急性电生理学方法，研究了中脑被盖对面部肌肉组织影响的突触通路的组织。在戊巴比妥钠麻醉下，在电刺激大脑膜旁区后，在逆向识别的面部运动神经元中记录细胞内的突触电位。使用辣根过氧化物酶 (HRP) 的逆行转运来定义起源细胞和负责从副系膜区诱发电位的通路。通过注射利多卡因使该核失活，以及通过造成急性脑干损伤以切断副脑膜-面部和其他传入通路，研究了脑膜旁区在面部运动神经元中产生非突触、构造诱发电位方面的假定作用。 2. 刺激大脑膜旁后，在供应耳廓肌肉的颞部和耳后部的运动神经元中记录了单突触兴奋性突触后电位 (EPSP)，其潜伏期为 0.6 至 0.9 ms、陡峭的上升阶段和超过 4.0 mV 的振幅。在颧骨细分中观察到具有单突触潜伏期的较小幅度 EPSP（小于 1.0 mV）。在所有这三个细分中也观察到延迟范围为 1.0 至 1.8 毫秒的多突触 EPSP。然而，腹侧细分运动神经元中仅存在长潜伏期 EPSP（到达 2.0 毫秒或更晚）。 3. 大脑皮层刺激后，面部运动神经元也经常记录到抑制性突触后电位（IPSP）。在颞颧和耳后分区的面部运动神经元中记录了潜伏期为 0.8 至 1.2 ms 且幅度超过 4.0 mV 的单突触 IPSP，潜伏期为 1.2 至 1.8 ms 的多突触 IPSP 也是如此。有时会观察到 IPSP 与更小、延迟更短的 EPSP 结合使用。在腹侧细分运动神经元中仅记录了大于 2.0 ms 的长潜伏期 IPSP。在所有情况下，EPSP 和 IPSP 都按特征进行分级，并且可以通过多种刺激来增强。 4.对侧侧脑膜区和双侧动眼上区代表面核注射 HRP 后标记的两个最突出的传入源。通过逆行标记细胞的存在，上丘和许多网状形成区域也被鉴定为面核传入神经。脑膜旁区逆行标记的细胞表现出异质体大小。观察到侧脑膜-面部通路的 HRP 标记轴突通过腹侧行进到尾部中脑的臂结膜，穿过中线。（摘要截断为 400 字）
1. The organization of the synaptic pathways underlying midbrain tegmentum influence over the facial musculature was studied with the use of an acute electrophysiological approach in the cat. Under pentobarbital sodium anesthesia, synaptic potentials were recorded intracellularly in antidromically identified facial motoneurons following electrical stimulation of the paralemniscal zone. The cells of origin and the pathways responsible for the potentials evoked from the paralemniscal zone were defined with the use of retrograde transport of horseradish peroxidase (HRP). The putative role of the paralemniscal zone with regard to the production of disynaptic, tectally evoked potentials in facial motoneurons was investigated both by inactivating this nucleus with injections of lidocaine and by making acute brain stem lesions to sever the paralemniscal-facial and other afferent pathways. 2. Following paralemniscal stimulation, monosynaptic, excitatory postsynaptic potentials (EPSPs) with latencies ranging from 0.6 to 0.9 ms, steep rising phases, and amplitudes in excess of 4.0 mV were recorded in motoneurons of the temporal and auriculoposterior subdivisions, which supply the pinna muscles. Smaller amplitude EPSPs (less than 1.0 mV) with monosynaptic latencies were observed in the zygomatic subdivision. Polysynaptic EPSPs with latencies ranging from 1.0 to 1.8 ms were also observed in all three of these subdivisions. However, only long-latency EPSPs, arriving at 2.0 ms or later, were present in ventral subdivision motoneurons. 3. Inhibitory postsynaptic potentials (IPSPs) were also frequently recorded in facial motoneurons after paralemniscal stimulation. Monosynaptic IPSPs with latencies ranging from 0.8 to 1.2 ms and amplitudes in excess of 4.0 mV were recorded in facial motoneurons of the temporozygomatic and auriculoposterior subdivisions, as were polysynaptic IPSPs with latencies ranging from 1.2 to 1.8 ms. IPSPs were sometimes observed in combination with a smaller, shorter latency EPSPs. Only long-latency IPSPs of greater than 2.0 ms were recorded in ventral subdivision motoneurons. In all cases, both the EPSPs and the IPSPs were graded in character and could be augmented by multiple stimuli. 4. The contralateral paralemniscal zone and the supraoculomotor area, bilaterally, represented the two most prominent afferent sources labeled after HRP injection of the facial nucleus. The superior colliculus and numerous reticular formation regions were also identified as facial nucleus afferents by the presence of retrogradely labeled cells. The retrogradely labeled cells in the paralemniscal zone exhibited heterogeneous soma size. HRP-labeled axons of the paralemniscal-facial pathway were observed to cross the midline by traveling ventral to the brachium conjunctivum in the caudal mesencephalon.(ABSTRACT TRUNCATED AT 400 WORDS)