Sodium-sensor ion channel that acts specifically in salt taste chemosensation. Required for salt-evoked neuronal activity and behavioral avoidance of high concentrations of NaCl. Expressed in the ASH polymodal avoidance neurons. Also expressed in other sensory neurons, including the ADF, ASE, ADL, AQR, PQR, URX and PHA cells. No apparent defect in nose touch avoidance but mutants show strong defects in the avoidance of NaCl concentrations above 100 mM. Responses to other soluble repellents as well as to hyperosmolarity are indistinguishable from wild-type animals. Belongs to the TMC family.