Nitric oxide synthase 1 (neuronal), also known as NOS1, is an

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

that in humans is encoded by the ''NOS1''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

Function

Nitric oxide synthases () (NOSs) are a family of synthases that catalyze the production of

nitric oxide Nitric oxide (nitrogen oxide, nitrogen monooxide, or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes den ...

(NO) from L-arginine. NO is a chemical messenger with diverse functions throughout the body depending on its enzymatic source and tissue localization. In the brain and peripheral nervous system, where NOS1 is largely present, NO displays many properties of a

neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a Chemical synapse, synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotra ...

and may be involved in long term potentiation. It is implicated in neurotoxicity associated with

stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...

and neurodegenerative diseases, neural regulation of smooth muscle, including

peristalsis Peristalsis ( , ) is a type of intestinal motility, characterized by symmetry in biology#Radial symmetry, radially symmetrical contraction and relaxation of muscles that propagate in a wave down a tube, in an wikt:anterograde, anterograde dir ...

and sphincter relaxation, and penile erection. NO is also responsible for endothelium-derived relaxing factor activity regulating blood pressure as produced from its related enzyme NOS3. In

macrophage Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that ...

s, NO mediates tumoricidal and bactericidal actions, as produced from its related enzyme NOS2. Various pharmacological inhibitors of NO synthases (NOS) block these effects, but further distinction of their function has been elucidated by animal models in which these specific genes have been inactivated. Neuronal NOS (NOS1), Endothelial NOS (NOS3), and Inducible NOS macrophage NOS are distinct isoforms. Both the neuronal and the macrophage forms are unusual among oxidative enzymes in requiring several electron donors: flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN), NADPH, and tetrahydrobiopterin.

Clinical significance

It has been implicated in

asthma Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...

schizophrenia Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...

, restless leg syndrome, and psychostimulant neurotoxicity. It has also been investigated with respect to

bipolar disorder Bipolar disorder (BD), previously known as manic depression, is a mental disorder characterized by periods of Depression (mood), depression and periods of abnormally elevated Mood (psychology), mood that each last from days to weeks, and in ...

and

air pollution Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...

exposure.

Interactions

NOS1 has been shown to interact with DLG4 and NOS1AP.

Function

Clinical significance

Interactions

See also

References

Further reading