Relationship between GAD/GABA and Sweet, Umami and Bitter Tastes, Those Received in Type II Taste Buds

Abstract

Food extracts from spices and teas were examined for the taste altering ability on sweet, umami and bitter tastes by using the taste sensation test. The idea arose based upon the findings that 1) some food extracts from spices and teas act as salt taste enhancers and 2) the enhancing effect is directly proportional to glutamate decarboxylase 67 (GAD67) activity in vitro. Our results indicated that those extracts significantly activated or inhibited GAD67 enzyme activity were able to alter sweet, umami, and bitter tastes. However, there were no relationships between the taste potency of each of the examined extracts and the GAD67 relative activity ratio. While it is unlikely that the extracts have directly activated GAD67 activity and enhanced sweet, umami or bitter tastes, the results do not exclude the idea that GABA may participate in the taste cell-to-cell communications.