Neuroscientist researchers at Emory University found that mice with a reduced capacity to store dopamine developed symptoms that mimic Parkinson’s disease. The mice had a reduced amount of the gene VMAT2, which caused a loss of dopamine neurons, in addition to many of the other neurochemical features observed in Parkinson’s disease patients.

The VMAT2 gene packages dopamine into tiny containers for future release by brain cells. When insufficient VMAT2 is produced, the result is that an insufficient amount of dopamine is available and neurodegenerative changes occur—a process known as the nigrostriatal dopamine system. The nigrostriatal region is in the deepest areas of the brain and damage to this region is what leads to the movement difficulties observed in Parkinson’s patients.