Neuronal NOS (nNOS) is an enzyme that produces nitric oxide, a signaling molecule, in the nervous system. It is primarily found in neurons and plays a crucial role in neurotransmission, influencing various brain functions such as learning and memory. nNOS is activated by calcium ions and is involved in the regulation of blood flow in the brain. nNOS is part of a larger family of nitric oxide synthases, which also includes endothelial NOS (eNOS) and inducible NOS (iNOS). Each of these enzymes has distinct functions and locations in the body. Dysregulation of nNOS can contribute to neurological disorders, highlighting its importance in maintaining healthy brain function.