Previous studies in animal models and in humans have shown that different pathological conditions in the gastrointestinal tract (inflammation, gastric ulcers, treatment with nonsteroidal anti-inflammatory drugs (NSAIDs), diabetes mellitus, mycotoxins in feed or bisphenol-A intoxication) changed the neurochemical profile of the enteric neurons and had a significant effect on modifying the number of CART-, nNOS- or VAChT-immunoreactive neurons [2,7,10,11,17,18,19]. Here, NOS1 is linked to diabetes mellitus.