Guglielmone R
Dipartimento di Scienze Cliniche e Biologiche, Università di Torino, Ospedale San Luigi Gonzaga, Italy.
Cell Tissue Res. 1995 Jul;281(1):163-8. doi: 10.1007/BF00307970.
Although the cerebrospinal fluid-contacting neurons of the avian paraventricular organ exhibit considerable amounts of catecholamines, they show no tyrosine hydroxylase immunoreactivity. In the quail embryo, the development of these neurons has been studied using the paraformaldeyde-glutaraldeyde method for the fluorescence-histochemical localization of catecholamines. The timing of the appearance of catecholamine fluorescence in cerebrospinal fluid-contacting neurons and that in catecholamine-containing neurons of the brainstem have been compared. The first neurons displaying catecholamine fluorescence are found within the locus coeruleus and the nucleus subcoeruleus ventralis on the 5.5th day of incubation. Catecholaminergic neuronal groups of the medulla and mesencephalon can be identified by embryonic day 7, and fluorescent cerebrospinal fluid-contacting neurons of the hypothalamic paraventricular organ can be first recognized at the 8th day of incubation. If the catecholamine content of cerebrospinal fluid-contacting neurons that lack tyrosine hydroxylase depends upon an uptake mechanism, it may be significant that, in fluorescence-histochemical preparations, these neurons can be identified 1-3 days later than those in which catecholamines are synthesized and from which catecholamines are released at an earlier developmental stage. Moreover, cerebrospinal fluid-contacting neurons that have previously been shown to be tyrosine-hydroxylase immunoreactive, and that lie at the spinal-medullary junction display a different developmental pattern. By fluorescence histochemistry, they can be detected only by embryonic day 10.5. The chemical, developmental and topographical differences suggest that the catecholamine-containing cerebrospinal fluid-contacting elements of the paraventricular organ and those of the spinal cord represent two different subsets of cerebrospinal fluid-contacting neurons whose respective functional roles remain to be investigated.
尽管鸟类室旁器官的脑脊液接触神经元含有大量儿茶酚胺，但它们没有酪氨酸羟化酶免疫反应性。在鹌鹑胚胎中，已使用多聚甲醛-戊二醛法对这些神经元的发育进行了研究，以进行儿茶酚胺的荧光组织化学定位。比较了脑脊液接触神经元和脑干中含儿茶酚胺神经元中儿茶酚胺荧光出现的时间。在孵化第5.5天时，在蓝斑和蓝斑下核腹侧首次发现显示儿茶酚胺荧光的神经元。延髓和中脑的儿茶酚胺能神经元群在胚胎第7天可被识别，下丘脑室旁器官的荧光脑脊液接触神经元在孵化第8天首次被识别。如果缺乏酪氨酸羟化酶的脑脊液接触神经元的儿茶酚胺含量取决于摄取机制，那么在荧光组织化学制剂中，这些神经元比那些合成儿茶酚胺并在更早发育阶段释放儿茶酚胺的神经元晚1 - 3天才能被识别，这可能具有重要意义。此外，先前已证明位于脊髓-延髓交界处的脑脊液接触神经元具有酪氨酸羟化酶免疫反应性，但其发育模式不同。通过荧光组织化学，它们直到胚胎第10.5天才能被检测到。化学、发育和地形学上的差异表明，室旁器官和脊髓中含儿茶酚胺的脑脊液接触元件代表了脑脊液接触神经元的两个不同亚群，它们各自的功能作用仍有待研究。
