Zhan W Z, Ellenberger H H, Feldman J L
Department of Kinesiology, University of California, Los Angeles 90024-1568.
Neuroscience. 1989;31(1):105-13. doi: 10.1016/0306-4522(89)90033-x.
The termination patterns of axons in the phrenic nucleus immunoreactive to synthetic enzymes for catecholamines and for serotonin and GABA were studied in rats. Spinal cord tissue in which phrenic motoneurons were retrogradely labeled with horseradish peroxidase was incubated with antisera against dopamine beta-hydroxylase, phenylethanolamine-N-methyltransferase, 5-hydroxytryptamine, and GABA to identify presumptive terminations of monoaminergic and GABAergic neurons onto identified phrenic motoneurons. In the C3 to C5 spinal cord, 5-hydroxytryptamine-, dopamine beta-hydroxylase- and GABA-like positive terminals with varicosities formed a dense network, with presumptive synaptic contacts on dendrites and somas of phrenic motoneurons. A similar pattern of terminations was also observed in adjacent (non-respiratory muscle) motoneuron pools. There were fewer phenylethanolamine-N-methyltransferase-positive terminal arborizations in the cervical spinal cord compared to thoracic spinal cord; phenylethanolamine-N-methyltransferase terminals were not seen in the vicinity of phrenic motoneurons. These results suggest that phrenic motoneuronal activity is influenced by multiple supraspinal inputs utilizing different neurotransmitters. These transmitters also mediate inputs to other (nearby) spinal motoneurons and thus are not unique for signal transmission to phrenic motoneurons.
在大鼠中研究了对儿茶酚胺、5-羟色胺和γ-氨基丁酸合成酶免疫反应的膈神经核中轴突的终末模式。将用辣根过氧化物酶逆行标记膈运动神经元的脊髓组织与抗多巴胺β-羟化酶、苯乙醇胺-N-甲基转移酶、5-羟色胺和γ-氨基丁酸的抗血清一起孵育，以鉴定单胺能和γ-氨基丁酸能神经元在已鉴定的膈运动神经元上的假定终末。在C3至C5脊髓中，有膨体的5-羟色胺、多巴胺β-羟化酶和γ-氨基丁酸样阳性终末形成密集网络，在膈运动神经元的树突和胞体上有假定的突触接触。在相邻的（非呼吸肌）运动神经元池也观察到类似的终末模式。与胸段脊髓相比，颈段脊髓中苯乙醇胺-N-甲基转移酶阳性终末分支较少；在膈运动神经元附近未见苯乙醇胺-N-甲基转移酶终末。这些结果表明，膈运动神经元的活动受利用不同神经递质的多个脊髓上输入的影响。这些递质也介导对其他（附近）脊髓运动神经元的输入，因此并非膈运动神经元信号传递所特有。
