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 physiological properties, such as the presence of neurotransmitter transporters and the expression of glutamine synthetase. However, there are distinguishing factors that put SGCs in their own distinct category of glial cells. SGCs most often surround individual sensory and parasympathetic neurons with a complete, unbroken sheath while most neurons of sympathetic ganglia lack a completely continuous SGC sheath, allowing for limited direct exchange of materials between the extracellular space of the neuron and the space within the connective tissue where the SGCs are situated. Furthermore, gap junctions exist between SGCs in the sheaths of adjacent neurons as well as between SGCs