GDNF (glial cell-line derived neurotrophic factor) is a natural brain substance involved in the embryonic establishment of the nigrostriatal dopaminergic system and maintenance of adult nigrostriatal dopaminergic neuron health.  With degeneration of these dopaminergic neurons critical to the neuropathology of PD, investigators have postulated that addition of exogenous GDNF to the nigrostriatal system may improve motor function by stimulating residual dopaminergic neuron function and preventing further degeneration.

…..Researchers at the University of Florida have been successful in controlling expression of a modified gene construct that includes GDNF, delivered to the brain of rodents by a single AAV vector (adeno-associated viral vectors).  The AAV vector was able to package not only the GDNF gene but also additional regulatory sequences which respond to dietary doxycycline in regulating gene expression. Control of GDNF expression may be important in avoiding clinical morbidity in Parkinson’s disease (PD) patients.