Sodium ion in salt (NaCl) excite taste cells in the taste buds by penetrating a specific ion channel called ENaC. The neural information is sent to the brain via the taste nerves and is processed to elicit salty taste. Animals prefer salt solutions at the isotonic concentration (0.15mol/l) and reject at the hypertonic concentrations. Females like salty taste more than males do. Under the salt appetite condition, animals show high sensitivity to weak salt solutions and low sensitivity to strong ones to facilitate ingestion of Sodium ion by changing the hedonic value. Brain mechanisms of palatability are described in terms of brain substances: palatability is enhanced by benzodiazepine derivatives and β-endorphin, the motivation to ingest is performed by dopamine and the ingestive behavior is executed by orexin.
