The bitter taste is mediated by the action of
Sweet- G protein coupled increased in cAMP causing closure of K+ channels.
Salt- Opening of amiloride sensitive Na+ channels
Sour- Increased intracellular H+ concentration causing closure of K+ channels
Bitter- G protein-coupled increase in intracellular Ca++ triggering neurotransmitter release.
Guanyl cyclase
G protein
Tyrosine kinase
Epithelial Na+ chain