GCG and irritable bowel syndrome: Our finding of increased levels of GLP-1R and sensory/nociceptor innervation in IBD gut tissues, and presence of GLP-1R in human DRG neurons, led to our studies of functional effects; we investigated the effects of oxyntomodulin, exendin-4 and GLP-1 on neurite length, and sensitivity to capsaicin and ATP, in cultured DRG neurons.