Dopamine Synthesis as a Mechanism of Brain Plasticity in Nigrostriatal System Pathology.

Using an experimental Parkinson's disease model (symptoms develop in mice after the injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), we studied the characteristics of the synthesis of dopamine as a possible compensatory mechanism aimed at maintaining the dopamine level in the dopaminergic neurons that survived in this pathology. We found no correlation between the content and activity of tyrosine hydroxylase in the nigrostriatal system. The enzyme activity and the dopamine content showed unidirectional changes in the substantia nigra, but not in the striatum, which is apparently due to triggering other compensatory mechanisms.