Westlund K N, Carlton S M, Zhang D, Willis W D
Department of Anatomy, University of Texas Medical Branch, Galveston 77550.
J Comp Neurol. 1990 Sep 8;299(2):178-86. doi: 10.1002/cne.902990205.
Catecholaminergic axonal varicosities identified by immunocytochemical staining for dopamine-beta-hydroxylase were observed at the light microscopic level apposing the somata of retrogradely labeled spinothalamic tract neurons in the monkey spinal cord. Three retrogradely labeled and two intracellularly labeled spinothalamic neurons were serially sectioned and examined at selected intervals at the electron microscopic level. Electron microscopic study revealed that axonal boutons directly contacted the somata and/or dendrites of lamina I, IV, and V spinothalamic tract neurons. All of the profiles apposing one of the retrogradely labeled lamina I spinothalamic tract neurons were categorized from eight planes of section spaced at 1-micron intervals. Of the 305 profiles counted that were adjacent to this soma, 17 (5.6%) stained positively for dopamine-beta-hydroxylase. Of these 17 appositions, three were followed in serial sections to confirm that they had synaptic thickenings and alignment of vesicles along the membrane contacting the spinothalamic tract soma. Catecholaminergic boutons were observed apposing the somata and dendrites of intracellularly filled STT cells characterized as high threshold and wide dynamic range neurons. These observations clearly indicate a direct innervation of spinothalamic tract neurons by catecholaminergic neurons, providing anatomical data to support previous physiological findings demonstrating that catecholamines modulate nociceptive transmission.
通过多巴胺-β-羟化酶免疫细胞化学染色鉴定的儿茶酚胺能轴突膨体，在光镜水平上观察到与猴脊髓中逆行标记的脊髓丘脑束神经元的胞体相邻。对三个逆行标记和两个细胞内标记的脊髓丘脑神经元进行连续切片，并在选定的间隔进行电子显微镜水平检查。电子显微镜研究显示，轴突终扣直接接触脊髓丘脑束I、IV和V层神经元的胞体和/或树突。与一个逆行标记的I层脊髓丘脑束神经元相邻的所有图像，从以1微米间隔的八个切片平面进行分类。在计数的与该胞体相邻的305个图像中，17个（5.6%）多巴胺-β-羟化酶染色呈阳性。在这17个相邻结构中，三个在连续切片中追踪，以确认它们具有突触增厚以及沿接触脊髓丘脑束胞体的膜排列的囊泡。观察到儿茶酚胺能终扣与细胞内填充的脊髓丘脑束细胞的胞体和树突相邻，这些细胞被表征为高阈值和宽动态范围神经元。这些观察结果清楚地表明儿茶酚胺能神经元对脊髓丘脑束神经元有直接支配，提供了解剖学数据以支持先前的生理学发现，即儿茶酚胺调节伤害性感受传递。
