[Nitric oxide in regulation of gastrointestinal and biliary motility]

In 1987 it was demonstrated that the vascular endothelium produces nitric oxide, a gas that acts as highly labile but very potent relaxing factor for the vascular smooth muscle. During the last 5-6 years, a series of discoveries from many different avenues of research came together revealing the major biological role of NO as neurotransmitter in the nervous system and other parts of the body, as a potent vasodilating and cytoprotective substance, as mediator of endotoxin-induced cytotoxicity and as a substance involved in various disorders such as liver cirrhosis and reactions of the immune system. Recent studies suggest that in addition to VIP and ATP, NO may mediate non-adrenergic, non-cholinergic (NANC) inhibition of gastrointestinal smooth muscle and related inhibitory junction potentials. The identity of action of NO and NANC nerve stimulation has been supported by numerous in vitro and in vivo studies on esophagus, stomach, small intestine and colon of various species including humans.