Characterization of Imidazopyridine Compounds as Negative Allosteric Modulators of Proton-Sensing GPR4 in Extracellular Acidification-Induced Responses. oleh Ayaka Tobo, Masayuki Tobo, Takashi Nakakura, Masashi Ebara, Hideaki Tomura, Chihiro Mogi, Dong-Soon Im, Naoya Murata, Atsushi Kuwabara, Saki Ito, Hayato Fukuda, Mitsuhiro Arisawa, Satoshi Shuto, Michio Nakaya, Hitoshi Kurose, Koichi Sato, Fumikazu Okajima