Scientists are finally beginning to find ways to grow new neurons.
Following chemotherapy and other incidents, nerve injury pain in the peripheral nervous system is rather common. Peripheral nerve injury pain has generally improved or ended over time if the severed neuron was able to grow back down the axon sheath and find the area it was intended to supply. This reconnection appears to shut off the pain. The alerted brain has been quieted. Such events are not available in central pain because central injury does not preserve a channel or empty axon sheath into which a regrowing neuron can track. Instead, there are many sprouts and the near end of the injured neuron, each of which is spewing out pain exciters, such exciters playing a dual role in hypersensitization and initiating regrowth.
Wernig et al in Proc Natl Acad Sci U S A
May (2008) have achieved a real breakthrough. They have been able to convert fibroblasts to neurons. These converted cells form into neurons, glia, and even dopaminergic cells. There has always been concern that converted cells might form tumors, but these scientists painstakingly separated the cells turned into neurons from pluripotential cells with fluorescent stains.
Certainly it is gratifying for scientists to finally unmask the transcription factors which will enable the formation of pluripotential cells into neurons. These transcription factors are:
transcription factors Oct4, Sox2, Klf4, and c-Myc
One can only hope the work will reach central nervous system neurons. The wheels of pain research grind slowly, but they grind exceeding fine.