Device and method for selectively ablating a submucosal layer of a duodenal wall and/or of sensory neurons therein, including a laser transmitting element coupled with the catheter body and configured to transmit a laser beam having a spot diameter of less than 200 microns and to provide an ablative dose of 0.5-2.5 J/mm； wherein the laser beam is configured to selectively ablate an area of the submucosal layer that is at least twice the size of the spot diameter, while essentially preventing damage of the surrounding mucosal, muscularis and/or serosal layers of the duodenal wall； and an expandable member configured to stretch the duodenal wall and to generate a fixed distance between the catheter's laser transmitting element and the duodenal wall.
