Unmyelinated axons in the feline trigeminal motor root.
The trigeminal motor root was studied in the electron microscope at different proximodistal levels in eight adult cats. Counts at a level halfway between the trigeminal ganglion and the pontine junction showed that the root contains about 9% (n = approximately 300) unmyelinated axon profiles at this level. Small groups of unmyelinated axons occur on both sides of the PNS-CNS border, in the surrounding pia mater, and in perivascular spaces of the CNS compartment. Examination of serial sections from the PNS-CNS transitional region showed that some unmyelinated axons actually cross the PNS-CNS border. The functional significance of these fibres remains unknown.
D000818:Animals; D001369:Axons / Q000648:ultrastructure; D002415:Cats; D002490:Central Nervous System / Q000648:ultrastructure; D005727:Ganglia, Spinal / Q000648:ultrastructure*; D008854:Microscopy, Electron; D009186:Myelin Sheath / Q000648:ultrastructure; D010525:Peripheral Nerves / Q000648:ultrastructure; D014276:Trigeminal Nerve / Q000648:ultrastructure*