Glial cell-line derived neurotrophic factor or GDNF is one of several naturally occurring proteins that the body requires in order to create, maintain, and grow nerve cells—also called neurons. Scientists working in laboratories using cell cultures and animals have previously shown that GDNF not only can protect brain cells from damage, but can also stimulate the growth of neurons, including dopamine neurons, the type of cells that are damaged in Parkinson’s disease. In some experiments, GDNF has been shown to “coax” damaged neurons into producing dopamine again, apparently by forming new nerve endings in damaged but still living dopamine neurons.
 
GDNF cannot be taken by mouth or via injection; instead, it is delivered directly into the brain. During an operation, a small pump to store the GDNF is implanted in the patient’s abdomen and a thin tube is tunneled under the skin and scalp and then fed through a hole in the skull into a specific portion of the brain called the putamen. Dopamine cells in the substantia nigra (the area of the brain that is affected by PD) make connections with cells in the putamen. Researchers hope that the GDNF that is delivered into the putamen will stimulate the remaining dopamine cells to form new nerve endings, thereby increasing the amount of dopamine overall.