[Morphological base of Renshaw inhibition studied by light and electron microscopic histochemistry. Topograhic...

Light- and electron microscopic structure of Renshaw elements--morphologic representatives of the recurrent spinal inhibition--was investigated by histochemical localization of AChE. Renshaw elements are spindle-shaped segments of the dendrites of the Renshaw cells and endings of the axoncollaterals of AChE-positive motoneurons are situated on them. Examination of serial sections of the L5-segment of the cat spinal cord revealed that the majority of Renshaw elements and the dendrit-arborization of interneurons of 3. type described by MATSUSHITA are lokalized in the same region. The fact that Renshaw elements in greatest amount could be found in that region of the anterior horn, where the Renshaw inhibition can be electrophysiologically elicited, seems to evidence they role in the latter.