TH and Parkinson disease: An in vivo PD model mice pre-administered with two doses of levodopa crystalsomes showed ameliorated 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced locomotor deficits, an enhanced expression of the tyrosine hydroxylase (TH) protein in striatal neurons, and an increased TH+ neuron expression in the substance nigra [65].