CROSS FOSTERING BETWEEN NORMAL AND SODIUM-RESTRICTED RATS - EFFECTS ON PERIPHERAL GUSTATORY FUNCTION

Rats restricted of dietary NaCl prenatally and thereafter exhibit abno rmally low electrophysiological chorda tympani taste responses to sodi um stimuli as adults. Recovery of responses can be induced by ingestio n of NaCl, even at adulthood. To examine whether milk from sodium-repl ete mothers enables functional recovery in sodium-restricted rats, we recorded multifiber chorda tympani responses in adult animals that had been cross fostered during the suckling period. Sodium-restricted ani mals cross fostered to control dams for postnatal weeks 1 and 2 did no t recover normal sodium sensitivity. Surprisingly, control pups crosse d to sodium-restricted mothers from postnatal days 1 to 14 showed an e xaggerated response to NaCl as adults. These results indicate that mil k from normal mothers ingested during postnatal weeks 1 and 2 is not s ufficient to restore gustatory function in sodium-restricted rats. Imp ortantly, it also appears that events occurring during the early suckl ing period of control rats determine long-term taste sensitivities to sodium.