PKCα Mediates Maternal Touch Regulation of Growth-Related Gene Expression in Infant Rats

Abstract

During short-term periods of separation of rat pups from their mothers, the loss of certain sensory signals suppresses the increase in ornithine decarboxylase (ODC) gene expression induced by the growth-promoting hormones prolactin (PRL) and growth hormone (GH). Here, we identify a molecular mechanism through which maternal separation (MS) curtails ODC expression. Our results demonstrate that the absence of specific tactile stimuli provided by the mother limits PRL-evoked stimulation of ODC biosynthesis by interfering with sn-1,2-diacylglycerol's (DAG) ability to activate protein kinase Ca (PKCa) and consequently c-myc mRNA and max mRNA expression. The proteins encoded by these proto-oncogenes function as direct transactivators of the ODC gene. As ODC activity is obligatory for normal cell replication and differentiation, PKCa activation by DAG represents an important control point at which 'nurturing touch' regulates growth and development of the neonate. Such a mechanism can explain the maladaptive consequences of disrupting mother-infant tactile interactions as occurs in isolated premature babies. Also, it could provide a basis for developing therapeutic interventions to maximize growth potential in children failing-to-thrive despite normal maternal care.

Acceleration of Visual System Development by Environmental Enrichment

“…Indeed, artificial manipulation and tactile stimulation in pups can influence eye opening in rodents (Barnett and Burn, 1967;Smart et al, 1990). In particular, tactile stimulation regulates the expression of hormones important for development (Kuhn and Schanberg, 1998;Schanberg et al, 2003), aids recovery from perinatal cortical lesions, and affects adult pattern of cortical cell dendritic fields (Kolb and Gibb, 1999). Interestingly, the increased levels of tactile stimulation could explain the increased levels of CRE-mediated gene expression that we observed in the somatosensory cortex of EC pups.…”

Massage Accelerates Brain Development and the Maturation of Visual Function

“…Artificial manipulation and tactile stimulation in pups can influence eye opening in rodents (Smart et al, 1990) and regulates the expression of hormones important for development (Kuhn and Schanberg, 1998;Schanberg et al, 2003). The effect of tactile stimulation on visual development is, however, totally unknown.…”

Effects of neonatal novelty exposure on sexual behavior, fear, and stress‐response in adult rats

“…A balanced environmental stimulation, basically provided by the mother, would be required for an adequate behavioral development. Similarly, enzymatic systems, like ornithine decarboxylase, which is involved in the development of several structures (Gilad, Rabey, Eliyayev, & Gilad, 2000;Schanberg, Ingledue, Lee, Hannun, & Bartolome, 2003), require optimum levels to exert their actions. We may suppose that the long-lasting behavioral and neuroendocrine effects described for the neonatal handling paradigm, in which the whole litter is manipulated and briefly separated from the mother (Levine et al, 1967;Liu et al, 1997;Meerlo et al, 1999;Padoin et al, 2001;Severino et al, 2004;Tang, 2001;Tang, Nakazawa, & Reeb, 2003), could be, in fact, due to the exposition of the pups to a novel environment and the consequent absence of maternal odor.…”