Pyrilamine normalized the sensitized Ca2+ response to capsaicin in DRGs incubated with PI-IBS biopsy supernatants (Fig. 4C), and PI-IBS supernatants were not able to potentiate the capsaicin response in DRGs collected from Hrh1 knock-out mice (Fig. 4C). This evidence concerns the gene HRH1 and irritable bowel syndrome.