Minson J, Llewellyn-Smith I, Neville A, Somogyi P, Chalmers J
Department of Medicine, School of Medicine, Flinders University of South Australia, Bedford Park.
J Auton Nerv Syst. 1990 Jul;30(3):209-20. doi: 10.1016/0165-1838(90)90252-e.
Spinal projections of the phenylethanolamine N-methyltransferase (PNMT) immunoreactive neurons of the medulla were investigated using a combination of immunohistochemistry and retrograde transport of colloidal gold particles conjugated to cholera toxin B subunit (CTB-gold). The PNMT-containing adrenergic neurons were localised in three groups, the C1 group in the rostral ventrolateral medulla, the C2 group in the nucleus tractus solitarius/dorsal vagal motor complex in the dorsal medulla and the C3 group in the mediodorsal medulla. The C1 group contained 72% of the medullary PNMT-IR neurons, while C2 comprised 13% and C3 15% of the medullary PNMT-IR neuron population. CTB-gold was injected in the area of the intermediolateral cell column in either upper (T2-T4) or lower (T8-T9) thoracic spinal cord and retrogradely labelled cells were found in the areas of the C1, C2 and C3 groups and in other regions of the medulla which did not contain PNMT-IR neurons. After tracer injections bilaterally at levels T2-T4, retrograde labelling suggested that at least 21% of all medullary PNMT-IR neurons projected to these levels. As a proportion of each group, 26% of C1, 9% of C2 and 33% of C3 neurons projected spinally to T2-T4. After tracer injections bilaterally at levels T8-T9, retrograde labelling suggested that at least 17% of all medullary PNMT-IR neurons projected to these levels. As a proportion of each group, 16% of C1, 9% of C2 and 30% of C3 neurons projected spinally to T8-T9. These figures represent minimum numbers since it is impossible to ensure that every neuron has equal access to the tracer. The results demonstrate that contrary to previous belief, the PNMT-IR innervation of the spinal cord derives from PNMT-IR neurons in the dorsal medulla, as well as from the rostral ventrolateral medulla. Indeed 24% of the PNMT-IR neurons terminating at spinal cord levels T2-T4, and 35% of those terminating at levels T8-T9, derive from the dorsal (C2 and C3) medullary cell groups. Since the PNMT-IR projections are directed towards the intermediolateral cell column, it seems likely that all three groups of medullary adrenaline-containing neurons contribute to the regulation of sympathetic outflow.
运用免疫组织化学与霍乱毒素B亚基结合的胶体金颗粒（CTB-金）逆行转运相结合的方法，研究了延髓中苯乙醇胺N-甲基转移酶（PNMT）免疫反应性神经元的脊髓投射。含PNMT的肾上腺素能神经元定位于三组：C1组位于延髓头端腹外侧，C2组位于延髓背侧的孤束核/迷走神经背运动复合体，C3组位于延髓中间背侧。C1组包含72%的延髓PNMT免疫反应性神经元，而C2组占延髓PNMT免疫反应性神经元总数的13%，C3组占15%。将CTB-金注入胸段脊髓上部（T2-T4）或下部（T8-T9）的中间外侧细胞柱区域，在C1、C2和C3组区域以及延髓中其他不含PNMT免疫反应性神经元的区域发现了逆行标记的细胞。在T2-T4水平双侧注射示踪剂后，逆行标记表明至少21%的所有延髓PNMT免疫反应性神经元投射到这些水平。作为每组的比例，26%的C1、9%的C2和33%的C3神经元向脊髓投射至T2-T4。在T8-T9水平双侧注射示踪剂后，逆行标记表明至少17%的所有延髓PNMT免疫反应性神经元投射到这些水平。作为每组的比例，16%的C1、9%的C2和30%的C3神经元向脊髓投射至T8-T9。这些数字代表的是最小数量，因为不可能确保每个神经元都有同等机会接触到示踪剂。结果表明，与先前的观点相反，脊髓的PNMT免疫反应性神经支配不仅来自延髓头端腹外侧的PNMT免疫反应性神经元，还来自延髓背侧的神经元。实际上，终止于脊髓T2-T4水平的PNMT免疫反应性神经元中有24%，以及终止于T8-T9水平的神经元中有35%，来自延髓背侧（C2和C3）细胞群。由于PNMT免疫反应性投射指向中间外侧细胞柱，所有三组含肾上腺素的延髓神经元似乎都参与了交感神经输出的调节。
