Long-term peripheral infusion of nociceptin/orphanin FQ promotes hyperplasia, activation and migration of mucosal mast cells in the rat gastric fundus

► Peripheral nociceptin/orphanin FQ (N/OFQ) increases the density of mucosal mast cells in the gastric fundus ► N/OFQ promoted the activation of mucosal mast cells. ► N/OFQ decreased the contacts between mucosal mast cells and nerve fibers. ► The antagonist of N/OFQ receptor abolishes the stress-induced hyperplasia of mucosal mast cells.