The first aim of this study was to characterize the changes that can be observed in water-avoidance stress-induced rat model of diarrhoea-IBS by measuring the number and degranulation of MCs, the expression of PAR-2 and TNF-α proteins, the intestinal permeability, and the reorganization and abundance of TJ proteins. The gene discussed is F2RL1; the disease is irritable bowel syndrome.