These are explained more in detail below
PD is associated with severe loss of dopamine (DA) neurons in the substantia nigra (SN) and their striatal terminals, leading to dopamine depletion and consequential motor impairments
(16, 18, 19) How is Glutathione Made
Several studies suggest that antidepressants like the selective serotonin reuptake inhibitor (SSRI) fluoxetine increase BDNF levels and are dependent on normal TrkB signaling to elicit their behavioral effects [262, 263]
If severe B12 deficiency with neurological involvement is suspected, treatment should be initiated promptly without waiting for test results, and specialist advice may be needed
Ethics declarations Authors note These results were presented in parts at the Metabolomics in Life Science conference, 2728 January 2026, Ume, Sweden