Exp Neurobiol.  2012 Sep;21(3):83-93. 10.5607/en.2012.21.3.83.

Sensory Axon Regeneration: A Review from an in vivo Imaging Perspective

• Han SB
• Kim H
• Skuba A
• Tessler A
• Ferguson T
• Son YJ

• KMID: 2134998
• DOI: http://doi.org/10.5607/en.2012.21.3.83

Abstract

Injured primary sensory axons fail to regenerate into the spinal cord, leading to chronic pain and permanent sensory loss. Re-entry is prevented at the dorsal root entry zone (DREZ), the CNS-PNS interface. Why axons stop or turn around at the DREZ has generally been attributed to growth-repellent molecules associated with astrocytes and oligodendrocytes/myelin. The available evidence challenges the contention that these inhibitory molecules are the critical determinant of regeneration failure. Recent imaging studies that directly monitored axons arriving at the DREZ in living animals raise the intriguing possibility that axons stop primarily because they are stabilized by forming presynaptic terminals on non-neuronal cells that are neither astrocytes nor oligodendrocytes. These observations revitalized the idea raised many years ago but virtually forgotten, that axons stop by forming synapses at the DREZ.

Keyword

dorsal root entry zone; sensory nerve regeneration; NG2 glia; oligodendrocyte precursor cells; in vivo imaging; astrocytes

MeSH Terms

Animals
Astrocytes
Axons
Chronic Pain
Oligodendroglia
Presynaptic Terminals
Regeneration
Spinal Cord
Spinal Nerve Roots
Synapses