Molecular Mechanisms by which Maternal Touch Regulates Growth Related Gene Expression

Duke University, Durham NC

Investigators

Abstract

Survival of the mammalian neonate is highly dependent on its ability to process sensory information and then adapt to changes by choosing an appropriate behavioral and physiological condition. Because the mother normally comprises the prime source of sensory input, she essentially determines the infant's psychobiological state. Previous work from this laboratory has shown that the loss of certain tactile cues from the mother initiates in the rat pup and human infant a shift from a growth strategy to one of energy conservation and growth suppression until contact with the mother is re-established. Overall the specific goals of this project are 1) to define the roles of CNS Bata-endorphin and bombesin in mediating how tactile stimulation by the dam regulates cell development in the pups and 2) to determine the molecular mechanisms by which maternal tactile deprivation (MTD) suppresses peripheral organ responsivity to the growth-promoting hormones GH and prolactin. Growth-related molecular parameters i.e. DNA synthesis and expression of the ornithine decarboxylase (ODC) gene in developing organs will be assessed and used as indices of the altered maturation resulting from MTD. The similarities between MTD syndrome in rat pups and human babies suggest a common etiology. Hence, identifying the underlying mechanisms by which maternal-infant interactions optimize growth potential in the neonate is essential in order to advance our understanding of the basic principles governing normal mammalian development. As ODC activity is obligatory for normal cell replication and differentiation, these mechanisms represent an important control point at which "nurturing touch" regulates neonatal development. Such a mechanism can explain the maladaptive consequences of disrupting mother-infant tactile interactions as occurs in isolated premature and in non-organic failure to thrive human infants.