Integrating Dopamine and BDNF Hypotheses: The Role of Dopamine–BDNF Crosstalk in Neuropathologies

The dopamine system plays an important role in numerous physiological processes, such as locomotion, emotions, reward behavior, memory, and learning. Differentiation and proper functioning of dopaminergic neurons are largely promoted by the brain-derived neurotrophic factor (BDNF). BDNF is one of the most abundant neurotrophins in the mammalian brain and is implicated in neuronal development, differentiation, and plasticity. Dysfunction of dopaminergic system and BDNF signaling are linked to the pathogenesis of many neurological disorders, including Parkinson's disease, schizophrenia, autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and others. Accumulating evidence indicates a significant crosstalk between BDNF and dopamine system, the disruption of which might underlie the development of various neuro- and psychopathologies. In this review, we summarized recent data on the interplay between BDNF and brain dopamine system under physiological conditions, as well as in neurodevelopmental and neurodegenerative disorders. The available data suggest that the crosstalk between the brain dopamine system and BDNF is essential for normal neurophysiology; it is also involved in neuropathology and could serve as a target for therapeutic strategies aimed at correcting pathological behaviors.