Om at NO har en tosidig effekt som både smertedempende og smerteøkende.

http://www.ncbi.nlm.nih.gov/pubmed/21723953
«Nitric oxide is an important neurotransmitter involved in the nociceptive process and, in the dorsal horn of the spinal cord, it contributes to the development of central sensitization. On the other hand, experimental data have also demonstrated that NO inhibits nociception in the peripheral and also in the central nervous system. »

«In addition, it has been shown that nitric oxide mediates the analgesic effect of opioids and other analgesic substances. «