Unmyelinated sensory and preganglionic fibers in rat L6 and S1 ventral spinal roots.
Approximately 30% of the axons in the L6 and S1 ventral roots in the rat are unmyelinated. Appropriate surgical procedures show that 30% of these unmyelinated axons arise from dorsal root ganglion cells and are therefore presumably sensory. Thus approximately 10% of the total number of axons in these ventral roots are sensory. The other 70% of the unmyelinated axons come from the spinal cord and are therefore presumably preganglionic parasympathetic fibers. Thus approximately 20% of the axons in these ventral roots are unmyelinated preganglionic fibers. The implications of these findings are discussed.
D000818:Animals; D001339:Autonomic Fibers, Preganglionic / Q000648:ultrastructure; D002452:Cell Count; D005727:Ganglia, Spinal / Q000601:surgery; D008854:Microscopy, Electron; D009412:Nerve Fibers / Q000648:ultrastructure*; D009475:Neurons, Afferent / Q000166:cytology; D010525:Peripheral Nerves / Q000601:surgery; D051381:Rats; D013126:Spinal Nerve Roots / Q000166:cytology* / Q000601:surgery; D013562:Sympathectomy