Extension of dorsal horn neurons into the severed and implanted dorsal root.

After dorsal root ganglionectomy in adult rats, the dorsal root was cut close to the spinal cord and implanted into the dorsal horn. Outgrowth from neurons in he dorsal horn of the spinal cord into the implanted dorsal root could be demonstrated after 3 months by means of retrograde HRP labeling. Double-labeling experiments showed that some of these neurons had retained their central projections while extending new processes into the implanted root. The possibility to reconstruct the sensory pathway by replacing the damaged primary sensory neuron with peripheral outgrowth from secondary sensory neurons is discussed.