Hyperexcitable neurons and altered non-neuronal cells in the compressed spinal ganglion
- Author:
- No author available
- Journal Title:
- ACTA PHYSIOLOGICA SINICA
- Issue:
- 5
- DOI:
- No doi available
- Key Word:
- radicular pain;dorsal root ganglion;neuronal hyperexcitability
Abstract： The cell body or soma in the dosal root ganglion (DRG) is normally excitable and this excitability can increase and persist after an injury of peripheral sensory neurons. In a rat model of radicular pain, an intraforaminal implantation of a rod that chronically compressed the lumbar DRG ("CCD" model) resulted in neuronal somal hyperexcitability and spontaneous activity that was accom-panied by hyperalgesia in the ipsilateral hind paw. By the 5th day after onset of CCD, there was a novel upregulation in neuronal expression of the chemokine, monocyte chemoattractant protein-1 (MCP- 1 or CCL2) and also its receptor, CCR2. The neurons developed, in response to topically applied MCP-1, an excitatory response that they normally do not have. CCD also activated non-neuronal cells including, for example, the endothelial cells as evidenced by angiogenesis in the form of an increased number of capillaries in the DRG after 7 days. A working hypothesis is that the CCD induced changes in neurons and non-neuronal cells that may act together to promote the survival of the injured tissue. The release of ligands such as CCL2, in addition to possibly activating nociceptive neurons (maintaining the pain), may also act to preserve injured cells in the face of ischemia and hypoxia, for example, by promoting angiogenesis. Thus, somal hyperexcitability, as often said of inflammation, may represent a double edged sword.
- [1]Zhang JM,LaMotte RH,Song XJ,etc.Mechanical and thermal hyperalgesia and ectopic neuronal discharge after chronic compression of dorsal root ganglia.[J].1999,82(6).
- [2]Donnelly DF,Tan ZY,LaMotte RH.Effects of a chronic compression of the dorsal root ganglion on voltage-gated Na+ and K+ currents in cutaneous afferent neurons.[J].2006,95(2).
- [3]Ma C,Greenquist KW,Lamotte RH.Inflammatory mediators enhance the excitability of chronically compressed dorsal root ganglion neurons.[J].2006,95(4).
- [4]Amir R,Devor M.Chemically mediated cross-excitation in rat dorsal root ganglia.[J].1996,16(15).
- [5]E, Lang,A, Novak,P W, Reeh,etc.Chemosensitivity of fine afferents from rat skin in vitro.[J].1990,63.
- [6]Song XJ,Zhang JM,LaMotte RH.Enhanced excitability of sensory neurons in rats with cutaneous hyperalgesia produced by chronic compression of the dorsal root ganglion.[J].1999,82(6).
- [7]Ma C,LaMotte RH.Enhanced excitability of dissociated primary sensory neurons after chronic compression of the dorsal root ganglion in the rat.[J].2005,113(1).
- [8]Kanje M,Lundborg G,Sondell M.Vascular endothelial growth factor has neurotrophic activity and stimulates axonal outgrowth, enhancing cell survival and Schwann cell proliferation in the peripheral nervous system.[J].1999,19(14).
- [9]Peng YB,Wu J,Willis WD,etc.GABA(A) and 5-HT(3) receptors are involved in dorsal root reflexes: possible role in periaqueductal gray descending inhibition.[J].2001,86(1).
- [10]Miller RJ,Ren DJ,White FA,etc.Excitatory monocyte chemoattractant protein-1 signaling is up-regulated in sensory neurons after chronic compression of the dorsal root ganglion[J].2005,102(39).
- [11]Hanani M.Satellite glial cells in sensory ganglia: from form to function.[J].2005,48(3).
- [12]R H, LaMotte,C N, Shain,D A, Simone,etc.Neurogenic hyperalgesia: psychophysical studies of underlying mechanisms.[J].1991,66.
- [13]Xing JL,Hu SJ.An experimental model for chronic compression of dorsal root ganglion produced by intervertebral foramen stenosis in the rat.[J].1998,77(1).
- [14]Peters W,Charo IF.Chemokine receptor 2 (CCR2) in atherosclerosis, infectious diseases, and regulation of T-cell polarization.[J].2003,10(3).
- [15]Subang MC,Richardson PM.Influence of injury and cytokines on synthesis of monocyte chemoattractant protein-1 mRNA in peripheral nervous tissue.[J].2001,13(3).
- [16]Sun JH,Yang B,Donnelly DF,etc.MCP-1 enhances excitability of nociceptive neurons in chronically compressed dorsal root ganglia.[J].2006,96(5).
- [17]Calderon TM,D'Aversa TG,Eugenin EA,etc.MCP-1 (CCL2) protects human neurons and astrocytes from NMDA or HIV-tat-induced apoptosis.[J].2003,85(5).
- [18]LaMotte RH,Ma C,Yao H,etc.Upregulation of the hyperpolarization-activated cation current after chronic compression of the dorsal root ganglion.[J].2003,23(6).
- [19].Evidence for a central component of post-injury pain hypersensitivity[J].1983,306(5944).