Rat Dopamine Receptor D4 (DRD4) Protein

Background

DRD4 is a Gi/o-coupled G protein-coupled receptor of the D2-like dopamine receptor family, primarily expressed in brain regions associated with cognition, emotion, and reward, such as the prefrontal cortex, amygdala, and hippocampus. DRD4 plays a significant role in modulating attention, impulse control, and executive function, and its dysfunction has been linked to attention-deficit hyperactivity disorder (ADHD), schizophrenia, and other neuropsychiatric disorders. Notably, DRD4 is highly polymorphic, with variations in its gene (e.g., the 7-repeat allele) associated with ADHD susceptibility, novelty-seeking behavior, and addiction. DRD4 signaling inhibits adenylate cyclase activity, leading to reduced cyclic AMP (cAMP) levels, and influences downstream pathways like MAPK and protein kinase C (PKC), regulating neuronal excitability and plasticity. In addiction, DRD4 contributes to reward sensitivity and reinforcement learning, making it a target for substance abuse treatment. DRD4 is also expressed in peripheral tissues, where it modulates cardiovascular function and immune responses. Its polymorphic nature and role in attention and behavior make DRD4 a key target for ADHD therapeutics and neuropsychiatric research.