nNOS, or neuronal nitric oxide synthase, is an enzyme found primarily in the nervous system. It plays a crucial role in producing nitric oxide, a signaling molecule that helps regulate various functions, including blood flow and neurotransmission. nNOS is important for communication between nerve cells and is involved in processes such as learning and memory. This enzyme is one of three types of nitric oxide synthase, with the others being eNOS (endothelial) and iNOS (inducible). nNOS is activated by calcium ions and is typically found in neurons, where it contributes to the modulation of synaptic activity. Its proper functioning is essential for maintaining healthy brain activity and overall neurological health.