Developmental neurobiology of salt taste sensation.

A principal process in the homeostatic control of sodium levels is salt intake, and the sense of taste has a primary role in regulating ingestion. Because ingestion of sodium chloride (NaCl) is essential for life, the taste system for salt sensation might be expected to exhibit mature functional characteristics from very early development. However, major changes in gustatory nerve responses to NaCl take place during development. In sheep and rat, the peripheral nerve responses to NaCl are of low magnitude during early development. Progressively, the taste system acquires an increasing proportion of fibers that respond maximally to NaCl. The sodium responsiveness emerges in the context of shifting peripheral innervation patterns and the apparent addition of functional receptor membrane channels sensitive to the sodium transport blocker, amiloride. These developmental processes can be altered by early manipulation of sodium in the diet.