UC Davis

This chapter describes how early hormonal experience might influence the offspring. Because of the complexity associated with the birth process, the experimental approaches described focus on direct treatments given to offspring during the immediate postnatal period. Initial investigations have centered around the effects of early experiences on social behaviors and neuroendocrine processes that are known to be, in later life, peptide dependent or strongly influenced by oxytocin (OT) or arginine vasopressin (AVP), a related neuropeptide. Studies subject involve prairie voles, a highly social rodent species in which OT and AVP have been shown to be of particular importance to behavior and physiology. The OT system has exceptional plasticity and may be affected by a variety of developmental factors. OT neurons in adult rats have been described as "immature." These neurons have the capacity to change shape and form new synapses, in part through changes in the glia that normally separate neurons. Both OT and AVP may directly or indirectly influence cellular growth, death or motility, inflammation, or differentiation. The potential to remodel the nervous system, especially in early life, offers another process through which OT or AVP may have effects on physiology and behavior. The OTR is also susceptible to epigenetic regulation, for example, by silencing genes via methylation. The capacity of genes that code for receptors to be silenced or otherwise modified in early life may be particularly relevant to understanding the long-lasting consequences of early experiences, whether originating as behavioral or hormonal experiences. © 2008 Copyright © 2008 Elsevier Inc.