To determine whether the LPA2 and LPA5 receptors are involved in gastric ulcers induced by 0.3 M HCl/ethanol and indomethacin, we first examined the LPA2 and LPA5 receptor subtype expression levels under insults of 0.3 M HCl/ethanol and indomethacin by western blotting. The gene discussed is LPAR2; the disease is gastric ulcer.