FIGURE 3-4. An epithelial sodium channel (ENaC).

FIGURE 3-4An epithelial sodium channel (ENaC)

The epithelium is represented as a lipid (fat) bilayer (round circles), the area above the lipid bilayer (oral cavity) represents the outside of the taste receptor cell, and the area below the lipid bilayer is the interior of the taste receptor cell. The channel itself is made up of three protein units (alpha, beta, and gamma) that are represented by the cylindrical structures. This channel is thought to form a tunnel through the taste receptor cell that allows Na+ ions outside the cell to move inside the cell. This channel is quite specific to sodium, which may explain why few compounds are purely salty. Once sodium is inside the taste receptor cell it causes a cascade of biochemical reactions that result in the release of neurotransmitters that signal salt taste to the brain.

From: 3, Taste and Flavor Roles of Sodium in Foods: A Unique Challenge to Reducing Sodium Intake

Cover of Strategies to Reduce Sodium Intake in the United States
Strategies to Reduce Sodium Intake in the United States.
Institute of Medicine (US) Committee on Strategies to Reduce Sodium Intake; Henney JE, Taylor CL, Boon CS, editors.
Washington (DC): National Academies Press (US); 2010.
Copyright © 2010, National Academy of Sciences.

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