2014 Sensory Physiology


Step Bitter Sweet Umami Sour Salty
1 Receptor activation

Activation of the G-protein gustducin
(there are ~24 other G-proteins that have been identified)

entry of H+ or Na+ through leak channels
Sour: also closes K+ channels
3 Multiple second messenger pathways
4 Opening of voltage-gated Ca2+ channels
and/or release of Ca2+ from intracellular stores
5 Neurotransmitter release
ATP for bitter, sweet, umami
serotonin (5HT) for sour/salty


Email: Dr. Janet Fitzakerley | ©2014 University of Minnesota Medical School Duluth | Last modified: 4-feb-14 8:26 PM