Dr. Midkiff will conduct research on genetic and experiential antecedents of salt preference. Her experiments will examine the effect of sodium deprivation during gestation and lactation, with periodic sodium repletion, on the long-term salt preference of rats. Two genetic strains of laboratory rats will be used: Fischer-344, which do not spontaneously prefer salt solutions in any concentration, and outbred Wistar rats, which prefer and copiously ingest salt solutions at hypotonic and isotonic concentrations. Rats from both strains reared on a sodium- deficient diet will be compared with control animals receiving the same diet with 1% salt added. This study is designed to determine whether early experience with salt can alter salt preference in adulthood. Previous studies have not found any long-term alteration in salt ingestion as a result of early experience, although two studies have described an alteration in water ingestion. Dr. Midkiff's preliminary studies indicate that long-term salt preference may altered, at least in Wistar rats, by post-weaning sodium deprivation and repletion. Results from this study will be used to direct further research into the limits of behavioral change based on early experience, and into the genetic origins of salt preference.
