Tuchscherer M M, Knox C, Seybold V S
University of Minnesota Medical School, Department of Cell Biology and Neuroanatomy, Minneapolis 55455.
J Neurosci. 1987 Dec;7(12):3984-95. doi: 10.1523/JNEUROSCI.07-12-03984.1987.
Substance P- and cholecystokinin-like immunoreactivities have been shown to coexist in some, but not all, dorsal root ganglion cell bodies of the rat. Quantitative immunofluorescence techniques were used in the present study to describe densities of substance P- and cholecystokinin-like immunoreactive varicosities in several spinal cord nuclei. By combining simultaneous immunofluorescent techniques on one tissue section with computerized image processing, coexistence of substance P- and cholecystokinin-like immunoreactivity in varicosities was also quantified. By comparing spinal cord regions between normal and unilateral dorsal rhizotomy affected animals, densities of substance P- and cholecystokinin-like immunoreactive varicosities associated with primary afferent neurons were established. To determine the densities of immunoreactive varicosities that were related to unmyelinated primary afferent fibers, data were compared between normal animals and those treated neonatally with capsaicin. Four major observations were made: (1) Substance P- and cholecystokinin-like immunoreactivity coexist in populations of varicosities in sensory and autonomic regions of rat spinal segment L6. (2) Within the superficial laminae of the dorsal horn, varicosities containing both substance P- and cholecystokinin-like immunoreactivity and cholecystokinin-like immunoreactivity alone are of primary afferent neuron origin, but those containing only substance P-like immunoreactivity are most likely of spinal or descending neuronal origin. (3) Capsaicin-insensitive cholecystokinin-like immunoreactive varicosities were present predominantly in lamina I. These data suggest some cholecystokinin-like immunoreactive varicosities are associated with myelinated primary afferent neurons. (4) Primary afferent fibers containing substance P- and cholecystokinin-like immunoreactivity project to intermediate gray regions of the rat spinal cord. A large proportion of these fibers are capsaicin sensitive, suggesting that they are unmyelinated.
P物质和胆囊收缩素样免疫反应性已被证明共存于大鼠部分而非全部的背根神经节细胞体中。本研究采用定量免疫荧光技术来描述几种脊髓核中P物质和胆囊收缩素样免疫反应性曲张体的密度。通过在同一组织切片上联合使用同步免疫荧光技术和计算机图像处理，还对曲张体中P物质和胆囊收缩素样免疫反应性的共存情况进行了定量分析。通过比较正常动物和单侧背根切断术影响动物的脊髓区域，确定了与初级传入神经元相关的P物质和胆囊收缩素样免疫反应性曲张体的密度。为了确定与无髓初级传入纤维相关的免疫反应性曲张体的密度，对正常动物和新生期用辣椒素处理的动物的数据进行了比较。得出了四个主要观察结果：（1）P物质和胆囊收缩素样免疫反应性共存于大鼠L6脊髓节段感觉和自主区域的曲张体群体中。（2）在背角浅层层内，同时含有P物质和胆囊收缩素样免疫反应性以及仅含有胆囊收缩素样免疫反应性的曲张体起源于初级传入神经元，但仅含有P物质样免疫反应性的曲张体很可能起源于脊髓或下行神经元。（3）对辣椒素不敏感的胆囊收缩素样免疫反应性曲张体主要存在于I层。这些数据表明一些胆囊收缩素样免疫反应性曲张体与有髓初级传入神经元有关。（4）含有P物质和胆囊收缩素样免疫反应性的初级传入纤维投射到大鼠脊髓的中间灰质区域。这些纤维中很大一部分对辣椒素敏感，表明它们是无髓的。
