Researchers have difficulty blocking NO directly because the gas has a very short lifespan in the neuron. Additional research on animals also shows that NO is involved in neuron death. For example, studies determined that blocking NOS in the brain impedes the cell death that occurs from stroke as well as in other disorders such as Parkinson's disease. Researchers now are actively investigating compounds that can derail NOS, in order to create new therapies that will control NO and protect human neurons in a range of brain ailments. Scientists also are investigating other participants in NO's course of action in order to identify additional treatment targets.
Some researchers believe that excess NO creates nicks and breaks in the DNA of neurons.
The injuries in this important molecule activate PARP, which depletes energy sources in the cell, causing cell death. Scientists found that doses of small molecules that inhibit PARP reduce brain damage in a variety of animal stroke models. Many of the specifics of NO production are still unclear. For example, it's not known how often NO is produced or how involved different participants need to be in order to carry out the production. It's thought that the molecule glutamate can start the process by leaving a neuron and attaching to a molecule lining an adjacent neuron, known as the NMDA receptor.