<P> Under certain conditions, this can backfire: Fulminant infection (sepsis) causes excess production of nitric oxide by macrophages, leading to vasodilatation (widening of blood vessels), probably one of the main causes of hypotension (low blood pressure) in sepsis . The inducible isoform of nitric oxide synthase is expressed and produces cytotoxic levels of nitric oxide . </P> <Table> <Tr> <Td> </Td> <Td> This section relies too much on references to primary sources . Please improve this section by adding secondary or tertiary sources . (March 2017) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section relies too much on references to primary sources . Please improve this section by adding secondary or tertiary sources . (March 2017) (Learn how and when to remove this template message) </Td> </Tr> <P> Nitric oxide also serves as a neurotransmitter between nerve cells, part of its general role in redox signaling . Unlike most other neurotransmitters that transmit information only from a presynaptic to a postsynaptic neuron, the small, uncharged, and fat - soluble nitric oxide molecule can diffuse widely and readily into cells . Thus, it can act on several nearby neurons, even on those not connected by a synapse . At the same time, the short half - life of NO means that such action will be restricted to a limited area, without the necessity for enzymatic breakdown or cellular reuptake . </P>

Nitric oxide (no) is a gas neurotransmitter that