Glial scar brain and spinal cord. FGF2 has also been shown to increase astrocyte proliferation "in vitro". Ciliary neurotrophic factor (CNTF) is a cytosolic protein that is not secreted. CNTF has been shown to promote the survival of neuronal cultures "in vitro", and it can also act as a differentiator and trophic factor on glial cells. Further, CNTF has been previously shown to affect the differentiation of glial precursor cells "in vitro"; however, the influence of CNTF in the "in vivo" setting has only recently been determined. Winter "et al." used CNTF over-expressing transgenic mice as well as wildtype controls that had
Satellite glial cell tumor necrosis factor α (TNFα) are other cellular factors that work to sensitize neurons to pain. SGCs are present in the PNS in fewer numbers than other more well-known types of glial cells, like astrocytes, but have been determined to affect nociception because of some of their physiological and pharmacological properties. In fact, just like astrocytes, SGCs have the ability to sense and regulate neighboring neuronal activity. First, after a period of nerve cell injury, SGCs are known to up-regulate GFAP and to undergo cell division. They have the ability to release chemoattractants, which are analogous to those released by