DEVELOPMENT OF SOME EARLY SENSORIMOTOR BEHAVIORS IN SODIUM-RESTRICTEDRATS

Rats exposed to low levels of dietary sodium throughout development ex hibit reduced chorda tympani nerve taste responses to sodium stimuli d uring adulthood, apparently due to altered activity of some hormone(s) or growth factor(s) during early development. We were concerned that such an alteration in the activity of some humoral factor(s) could aff ect development globally. To test this possibility, we utilized a batt ery of morphological and behavioral measures in neonatal, sodium-restr icted rats, expecting serious deficits to be reflected in altered onse t and expression of these behaviors. As compared with control rat pups , preweanling sodium-restricted mt pups exhibited greatly diminished b ody weight gain and delayed acquisition of several morphological featu res. However, in terms of sensorimotor development, no significant dif ferences between sodium-restricted and control rat pups were found. We interpret these results to indicate that despite significant somatic effects, sodium restriction may not influence the development of physi cal prowess or of early sensorimotor function in a global manner.