Ozaki S, Kudo N, Okado N
Department of Physiology, University of Tsukuba, Ibaraki, Japan.
J Comp Neurol. 1992 Nov 15;325(3):462-70. doi: 10.1002/cne.903250311.
Developmental changes in the coexistence of serotonin and substance P/enkephalin within single fibers of lamina IX of the rat lumbar spinal cord were examined by the use of a double-labelling immunohistochemical technique. On postnatal day (P) 0, 65.0% of immunoreactive varicosities contained only serotonin, and 21.3% of them had both serotonin and substance P. The coexistent ratio of serotonin and substance P in single fibers increased with development: 61.9% of serotonin positive varicosities co-contained substance P on P28, similar to the ratio found in adult animals (67.4%). The ratios of varicosities containing only substance P remained the same from P0 to adult stage (about 15%). Enkephalin positive immunoreactivity was not co-localized with serotonin positive varicosities at any stage of development. Although numerous serotonin positive fibers were found in lamina IX, only a few substance P and enkephalin positive fibers were observed in the same area on P0. The density of serotonin positive varicosities increased slightly by P28, whereas substance P and enkephalin positive fibers increased considerably by this age. Between P28 and the adult stage, the density of serotonin positive fibers decreased by about 50%. The cross sectional area of axonal varicosities containing serotonin- and substance P-like immunoreactivity was similar in both P0 and adult animals, whereas that of enkephalin positive fibers was different. We also examined the coexistence of serotonin and substance P within single neurons of the caudal raphe nuclei in P7 and adult animals, and found that the coexistent ratio significantly increased with development.
运用双标记免疫组织化学技术，研究了大鼠腰段脊髓IX层单纤维中5-羟色胺与P物质/脑啡肽共存情况的发育变化。出生后第0天（P0），65.0%的免疫反应性膨体仅含5-羟色胺，21.3%的膨体同时含有5-羟色胺和P物质。单纤维中5-羟色胺与P物质的共存比例随发育增加：P28时，61.9%的5-羟色胺阳性膨体同时含有P物质，与成年动物中的比例相似（67.4%）。仅含P物质的膨体比例从P0到成年阶段保持不变（约15%）。在发育的任何阶段，脑啡肽阳性免疫反应性均未与5-羟色胺阳性膨体重叠。虽然在IX层发现大量5-羟色胺阳性纤维，但在P0时，同一区域仅观察到少数P物质和脑啡肽阳性纤维。到P28时，5-羟色胺阳性膨体的密度略有增加，而此时P物质和脑啡肽阳性纤维显著增加。在P28和成年阶段之间，5-羟色胺阳性纤维的密度下降了约50%。P0和成年动物中，含5-羟色胺样和P物质样免疫反应性的轴突膨体横截面积相似，而脑啡肽阳性纤维的横截面积不同。我们还研究了P7和成年动物尾侧中缝核单个神经元中5-羟色胺与P物质的共存情况，发现共存比例随发育显著增加。
