A team of researchers from the University Clinic of Navarra has managed to improve parkinson's in monkeys by integrating dopamine --dopaminergic cells into the brain. These cells have been taken from the carotid body, through a small structure located in the area where the carotid artery branches off.
Parkinson's is related to the loss of dopaminergic neurons of black brain substance. Well, the cells of the carotid body, in addition to dopamine, release growth factors that cause the increase of the dopaminergic neurons of the brain.