Central nervous system nitric oxide actions

Enteric nerves control intestinal smooth muscle action and are connected to the brain by the autonomic nervous system. IBS is thought to result from dysregulation of this brain-gut axis. The enteric nervous system is composed of two gan-glionated plexuses that control gut innervation the submucous plexus (Meissner s plexus) and the myenteric plexus (Auerbach s plexus). The enteric nervous system and the central nervous system (CNS) are interconnected and interdependent. A number of neurochemicals mediate their function, including serotonin (5-hydroxytryptamine or 5-HT), acetylcholine, substance P, and nitric oxide, among others. 

The effects of VIP are mediated by G protein-coupled receptors, of which two subtypes termed VPAC1 and VPAC2 have been cloned from human tissues. Both subtypes are widely distributed in the central nervous system and in the heart, blood vessels, and other tissues. Binding of VIP to its receptors results in activation of adenylyl cyclase and formation of cAMP, which is responsible for the vasodilation and many other effects of the peptide. Other actions may be mediated by nitric oxide and cGMP. 

Dawson VL, Dawson TM. 1995. Physiological and toxicological actions of nitric oxide in the central nervous system. Adv Pharmacol 34 323-342. 

Physiological and Toxicological Actions of Nitric Oxide in the Central Nervous System... 

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