ADORA3 and asthma: In an effort to study the role of the A3AR in mast cell degranulation and development of A3AR antagonists for allergic conditions especially for asthma (to evaluate the pharmacological effects of human A3AR antagonists in mice or rats), Yamano et al. (2005) generated A3AR-humanized mice, in which the mouse A3AR gene was replaced by its human homolog, the authors found that human A3AR can activate intracellular Ca2+ mobilization but not the mouse PI3K-γ signaling pathway.