Dopaminergic System: A Potential Therapeutic Target for Alzheimer’s and Parkinson’s Diseases

Dopamine is a critical neurotransmitter involved in the regulation of motor control, cognition, reward processing, motivation, and neuroendocrine functions. Increasing evidence indicates that disturbances in dopaminergic neurotransmission contribute significantly to the pathogenesis of major neurodegenerative disorders, particularly Parkinson’s Disease (PD) and Alzheimer’s Disease (AD). The dopaminergic system comprises specialized neuronal populations, dopamine receptors, and transporter proteins that collectively maintain synaptic dopamine homeostasis and neuronal signaling. Degeneration of dopaminergic neurons is a hallmark of PD, whereas emerging studies suggest that impaired dopamine signaling also plays an important role in the cognitive and behavioral deficits associated with AD. This review summarizes current knowledge regarding the involvement of dopaminergic pathways in neurodegeneration, with emphasis on receptor subtypes, dopamine transporter function, and neuronal vulnerability. Furthermore, it discusses established therapeutic interventions, including dopamine receptor agonists and other dopaminergic modulators, highlighting their clinical benefits and limitations. Recent advances in the field, such as biased receptor ligands, gene-based therapies, stem cell-mediated regeneration, and nanoparticle-assisted drug delivery systems, are also evaluated for their potential to enhance therapeutic efficacy and target specificity. In addition, commonly used experimental models for investigating dopaminergic dysfunction and disease progression are reviewed. Despite substantial progress, several translational challenges continue to hinder the development of disease-modifying treatments. A deeper understanding of dopaminergic signaling mechanisms and their interactions with neurodegenerative processes may facilitate the identification of novel therapeutic targets. Future strategies should focus not only on symptomatic management but also on slowing or preventing disease progression through precise modulation of dopaminergic networks.