Bitter taste is mediated by action of:

Ans. B. G proteina. Taste pathways: -b. Receptor stimulation: -i. For sour Via mammaliondegenerin-I and by activating H+ -gated cation channelsii. For salt Via Epithelium sodium channels (ENaC) by direct application amiloride (diuretic) on tongue, inhibits the ENaC and abolishes the ability to taste salt.iii. For Sweet activating adenyl cyclase, via a heterotrimeric G-protein and the resulting increase in intracellular cAMP reduces K+ conductanceiv. For bitter: - By reducing cAMP via a heterotrimeric G-protein; and Increase IP3 and DAG. A novel G-protein named alpha - has been shown to occur in bitter taste cells that activates phosphodiesterase causing a decrease in intracellular cAMP