Development of some early sensorimotor behaviors in sodium-restricted rats

Rats exposed to low levels of dietary sodium throughout development exhibit reduced chorda tympani nerve taste responses to sodium stimuli during adulthood, apparently due to altered activity of some hormone(s) or growth factor(s) during early development. We were concerned that such an alternation in the activity of some humoral factor(s) could affect development globally. To test this possibility, we utilized a battery of morphological and behavioral measures in neonatal, sodium-restricted rats, expecting serious deficits to be reflected in altered onset and expression of these behaviors. As compared with control rat pups, preweanling sodium-restricted rat pups exhibited greatly diminished body weight gain and delayed acquisition of several morphological features. However, in terms of sensorimotor development, no significant differences 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 physical prowess or of early sensorimotor function in a global manner.