Figure 3.

Schematic diagram of Cl⁻ secretion stimulated by an odor tastant (thymol) in colonic epithelial cells. Activation of OR1G1 by luminal thymol increases [Ca²⁺]_i. The elevated [Ca²⁺]_i may modulate Ca²⁺-activated basolateral K⁺ channels, providing a driving force for the exit of Cl⁻/HCO₃ ⁻. Activation of OR1G1 may also activate TRPA1 although it is still unclear whether ORs are linked to TRPA1.