Regulatory Function of the Neurotransmitters on Inflammatory Responses

Neurotransmitters, including acetylcholine (ACh) and dopamine, play critical roles in regulating immune cell function and inflammatory responses across various pathologies. Beyond its classical neuronal role, ACh is actively secreted by diverse immune populations, including T cells, B cells, macrophages, dendritic cells, and natural killer cells. Upon binding to nicotinic (nAChRs) and muscarinic (mAChRs) acetylcholine receptors expressed on neutrophils, T cells, B cells, and monocytes/macrophages, ACh triggers intracellular signaling pathways that modulate immune cell proliferation, polarization, and cytokine secretion. Similarly, dopamine receptors (D1R–D5R) are widely expressed across these identical immune cell subsets. Dopamine signaling dynamically orchestrates immune cell proliferation, differentiation, activation, migration, polarization, and cytokine profiles. Consequently, these neurotransmitter-mediated pathways play pivotal roles in the pathogenesis of neurodegenerative, autoimmune, and systemic inflammatory diseases, including Parkinson’s disease, multiple sclerosis, inflammatory bowel disease, acute pancreatitis, chronic obstructive pulmonary disease, acute respiratory distress syndrome, infective endocarditis, and rheumatic heart disease.