HTR1A and irritable bowel syndrome: Our findings shed new light on the double-faced role of 5-HT in intestinal delayed inflammation: the prevailing deleterious contribution mediated by 5-HT2A and 5-HT4 receptors activation co-exists and is partially counteracted by 5-HT1A stimulation, suggesting that agents targeting serotoninergic system could be beneficial as an additional therapeutic strategy in IBD only by carefully dissecting the monoamine antithetical effects.