LONDON, March 3 (Xinhua) -- Scientists have identified two cell proteins which trigger the stomach to relax when accommodating a big meal, offering a possible drug alternative to surgery in the fight against obesity, a BBC report said Monday.

    The two proteins identified by researchers at University College London are P2Y1 and P2Y11. They are embedded in the gut wall as well as muscle cells, said the report.

    The human stomach, which has a "resting" internal volume of 75 milliliters, can expand to an internal volume of two liters or more by relaxing its muscular wall. This expansion is controlled by nerves inside the stomach wall which release molecules that stimulate P2Y1 and P2Y11 receptor proteins, according to the researchers.

    "The mechanism of slow relaxation of the stomach might represent a future drug target in the fight to control weight gain and reverse obesity. We are looking to identify drugs that would block the P2Y11 receptor and, therefore, prevent slow relaxation of the stomach," Brian King, who led the research, was quoted as saying.

    As a result of blocking the P2Y11-based mechanism, a meal size would be smaller, offering a person a better chance to regulate food intake. This would represent a new approach to weight control, he added.

    At present, gastric banding or stomach stapling are popular ways to help people lose weight, both of which reduce the maximum volume of the stomach. But these are tricky surgical procedures, and carry the risk of serious side-effects, said the researchers.