Oxytocinergic input to the sympathetic preganglionic neurons in the rat. A light and electron microscopic study using immunocytochemical technique.

采用逆行细胞体标记和免疫组织化学相结合的方法，阐明了大鼠脊髓T_1至T_4期催产素能纤维与交感神经节前神经元（spn）的接触机制。用霍乱毒素亚基B （CTb）或辣根过氧化物酶偶联CTb逆行标记spn。在包括交感神经节前亚核在内的中间区发现催产素免疫反应纤维。在中央自主核和插层核中，经常观察到棕色染色的催产素- 1变异或终末与黑色染色的spn树突相连。电镜观察显示，催产素末端与交感神经节前神经元的树突或胞体形成突触。末端有许多小的透明圆形囊泡和一些大的有盖囊泡。这些结果清楚地表明，大部分spn是由含有催产素的纤维支配的。讨论了这些纤维的起源，认为它们可能是来自下丘脑室旁核的下行纤维。

A combination of retrograde cell body labeling and immunohistochemistry was employed to elucidate how oxytocinergic fibers make contact with sympathetic preganglionic neurons (SPNs) in the rat spinal cord from T_1 to T_4. SPNs were labeled retrogradely using cholera toxin subunit B (CTb) or horseradish peroxidase conjugated CTb. Oxytocin immunoreactive (ir) fibers were found in the intermediate zone including the sympathetic preganglionic subnuclei. In the central autonomic nucleus and the intercalated nucleus, brown-stained oxytocin-ir varicosities or terminals were frequently observed to stud black-stained dendrites of SPNs. Electron microscopical observations showed that oxytocin-ir terminals form synapses with dendrites or soma of the sympathetic preganglionic neurons. The terminals contained numerous small clear round vesicles and a few large cored vesicles. These results clearly show that a large part of SPNs is innervated by oxytocin containing fibers. The origin of these fibers is discussed, and it is concluded that they are probably descending fibers from the paraventricular nucleus of the hypothalamus.