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Title: Development Effects of Oxytocin in Piglets by Intranasal or Subcutaneous Administration

item RAULT, JEAN-LOUP - Purdue University
item CARTER, C - University Of Illinois
item Cheng, Heng Wei
item GARNER, JOSEPH - Purdue University
item Marchant, Jeremy
item RICHERT, BRIAN - Purdue University
item Lay Jr, Donald

Submitted to: Society for Neuroscience Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/3/2010
Publication Date: 10/13/2010
Citation: Rault, J., Carter, C.S., Cheng, H., Garner, J.P., Marchant Forde, J.N., Richert, B.T., Lay Jr, D.C. 2010. Development Effects of Oxytocin in Piglets by Intranasal or Subcutaneous Administration. Society for Neuroscience Abstracts and Proceedings. Proceedings.

Interpretive Summary:

Technical Abstract: Oxytocin (OT) is implicated in the regulation of social behaviors and reactivity to various stressors. Previous studies have evidenced that the effects of early experience, including postnatal social interactions, on socio-behavioral development are partly mediated by plasticity in peptide systems or 'hormonal imprinting'. Influences on the oxytocinergic system in early life could have long-term effects on the development of the central nervous system (CNS). The pig (Sus scrofa) is an increasingly popular biomedical research model since it shares anatomical, physiologic and neural developmental characteristics with humans; however the role of OT in the development of pig' CNS remains largely unexplored. The aim of this study was to examine the effects of early OT administration on the developmental organization of the oxytocinergic system in neonatal piglets. Simultaneously, we examined methods for delivering OT, either intranasally (IN) or by subcutaneous (SC) injection. IN administration has been assumed to reach the brain based on a study in humans using vasopressin, a closely related neuropeptide. However, whether OT-IN can directly affect central OT remains unclear. Furthermore, OT-SC has behavioral consequences, possibly in part by crossing the blood-brain barrier, especially in early development when the barrier is not fully formed. Piglets received daily on postnatal day 1, 2 and 3 either one of the following treatments: OT-IN (24 IU), OT-SC (1000 IU/kg), or saline-IN as control. In each litter, one male and one female received either one of the three treatments, replicated in 2 litters. Animals were perfused transcardially on day 21 to collect the brain tissues for analysis. To determine if exogenous OT treatment affected expression of endogenous OT immunoreactivity, a series of sections were immunohistochemically stained for OT in the paraventricular nucleus (PVN), the supraoptic nucleus (SON), and the amygdala. Quantitative analyses revealed no significant differences in the number of positive staining cells for OT in the PVN: 109.7 ± 14.2, 131.6 ± 19.7, and 137.3 ± 21.9 for OT-IN, OT-SC, and saline-IN, respectively. Responses were not sexually dimorphic. The present results suggest that exogenous OT, given either IN or SC, do not alter the OT-containing cells in the PVN of neonatal piglets as seen 3 weeks later. However, it is possible that the vasopressinergic system is modified, an effect seen in prairie voles and rats. Further research is required to determine the developmental effects of oxytocin and if OT administered intranasally is a viable non-invasive option to study its effects on central OT and behaviors in species other than humans.