Cruz F, Lima D, Zieglgänsberger W, Coimbra A
Institute of Histology and Embryology, Faculty of Medicine, University of Oporto, Portugal.
J Comp Neurol. 1991 Mar 1;305(1):3-16. doi: 10.1002/cne.903050103.
The fine structure and synaptic architecture of the afferent terminations in dorsal horn lamina II are studied using a combined light and electron microscopic procedure after anterograde labelling with horseradish peroxidase. Vibratome parasagittal sections, stained with heavy metal intensified diaminobenzidine after tracer application to the dorsal roots, were flat-embedded in Epon. The five types of labelled terminal arbors occurring in lamina IIi (Cruz et al., '87: J. Comp. Neurol. 261:221-236) were drawn and relocated in 5-microns sections cut serially from the thick sections. Ultrathin sections were then cut from the 5-microns sections so that the terminal fibers and swellings observed in the light microscope could be traced in the electron microscope. The flame-shaped arbors arose from fine myelinated stem fibers. Terminal strands generated large oval central terminals of type II synaptic glomeruli (CII), which established frequent axoaxonal contacts. Similar terminals have been labelled in the cat after tracer injections into hair-follicle fibers (Réthelyi et al., '82: J. Comp. Neurol. 207:381-393). The other four plexuses arose from unmyelinated stem fibers. The swarms of ultrafine boutons consisted of extremely thin terminal fibers generating very small, round, or polygonal glomerular terminals containing tightly packed agranular synaptic vesicles of variable size and one mitochondrion at best. The terminal strands of the bouquet plexus bore long and scalloped central varicosities of type I synaptic glomeruli (CI) with pleomorphic agranular vesicles and a relative abundance of dendroaxonal contacts. These features, together with the location in dorsal lamina IIi, suggest their belonging to the fluoride resistant acid phosphatase (FRAP)-reactive population. The boutons of the undulating fibers and those of the lateral plexus were, like those of the bouquets, scalloped and elongated rostrocaudally (CI), but contained a few large granular vesicles. The occurrence of the swarm, undulating, and lateral plexuses in ventral lamina IIi, which seems to lack FRAP or peptidergic terminals, suggests an origin from other, still unidentified neurochemical populations of fine primary afferents.
在用辣根过氧化物酶进行顺行标记后，采用光镜和电镜联合技术，研究了背角Ⅱ层传入终末的精细结构和突触构筑。将示踪剂注入背根后，用重金属强化二氨基联苯胺染色的振动切片机矢状旁切片，平嵌入环氧树脂中。绘制并重新定位了在Ⅱi层中出现的五种类型的标记终末树突（Cruz等人，1987年：《比较神经学杂志》261:221 - 236），这些切片是从厚切片上连续切取的5微米切片。然后从这些5微米切片上切取超薄切片，以便在电镜下追踪在光镜中观察到的终末纤维和膨体。火焰状树突起源于细有髓干纤维。终末链产生了Ⅱ型突触小球（CII）的大椭圆形中央终末，这些终末建立了频繁的轴 - 轴突接触。在将示踪剂注入毛囊纤维后，在猫身上也标记到了类似的终末（Réthelyi等人，1982年：《比较神经学杂志》207:381 - 393）。其他四个丛起源于无髓干纤维。大量的超细微终扣由极细的终末纤维组成，这些纤维产生非常小的圆形或多边形小球状终末，其中含有紧密堆积的大小不一的无颗粒突触小泡，最多有一个线粒体。花束丛的终末链带有Ⅰ型突触小球（CI）的长而有扇贝形的中央膨体，含有多形性无颗粒小泡，并且树突 - 轴突接触相对丰富。这些特征，连同其在背侧Ⅱi层的位置，表明它们属于抗氟酸性磷酸酶（FRAP）反应性群体。起伏纤维和外侧丛的终扣与花束丛的终扣一样，呈扇贝形且在头尾方向上拉长（CI），但含有一些大颗粒小泡。在似乎缺乏FRAP或肽能终末的腹侧Ⅱi层中出现大量、起伏和外侧丛，提示它们起源于其他尚未明确的神经化学性质的细初级传入纤维群体。
