Relationship between myelin sheath diameter and internodal length in axons of the anterior medullary velum of the adult rat.

摘要

Relations between myelin sheath diameters and internodal lengths were measured in whole mounts of osmium stained intact anterior medullary velum (AMV) from glutaraldehyde perfused adult rats. The AMV is a sheet of CNS tissue which roofs the IVth ventricle and contains fascicles of myelinated fibres which arise mainly from the nucleus of the IVth cranial nerve. These fibers displayed a broad range of myelin sheath external diameters and internodal lengths, from 4 microns. Our results indicated that small and large calibre fibres may have different myelin sheath diameter-internodal length interrelations.