Abnormal taste perception in mice lacking the type 3 inositol 1,4,5-trisphosphate receptor

Inositol 1,4,5-trisphosphate receptor (IP₃R) is one of the important calcium channels expressed in the endoplasmic reticulum and has been shown to play crucial roles in various physiological phenomena. Type 3 IP ₃R is expressed in taste cells, but the physiological relevance of this receptor in taste perception in vivo is still unknown. Here, we show that mice lacking IP₃R3 show abnormal behavioral and electrophysiological responses to sweet, umami, and bitter substances that trigger G-protein-coupled receptor activation. In contrast, responses to salty and acid tastes are largely normal in the mutant mice. We conclude that IP₃R3 is a principal mediator of sweet, bitter, and umami taste perception and would be a missing molecule linking phospholipase C β2 to TRPM5 activation.