The neuromodulatory effects of Pueraria lobata roots and Puerarin on the dopamine system.

Dopamine (DA) plays a critical role in brain function and is implicated in numerous neuropsychiatric disorders. This study investigated the neurochemical effects of Pueraria lobata (PL) and its bioactive compound, Puerarin (PUE), on dopaminergic neurotransmission. Using Institute of Cancer Research mice and SH-SY5Y neuroblastoma cells, we assessed neurotransmitter levels and DA-related protein expression. PL administration elevated 3-methoxytyramine (3-MT) levels in the nucleus accumbens and increased the expression of tyrosine hydroxylase (TH) and DA transporter (DAT), while downregulating the DA receptor subtypes DRD1 and DRD2, indicating a potential enhancement in dopaminergic signaling. In contrast, PUE treatment reduced TH expression and downregulated DRD1 and DRD2 expression without altering DAT levels, indicating a suppressive effect on the dopaminergic system. These findings demonstrate that PL and PUE exert distinct modulatory effects on dopaminergic signaling-PL enhancing and PUE inhibiting DA activity-highlighting their potential therapeutic applications for neurodegenerative disorders associated with dopaminergic dysfunction.