ESPE Yearbook of Paediatric Endocrinology

To read the full abstract: Neurosci Lett. 2020 Apr 23;725:134912. doi: 10.1016/j.neulet.2020.134912. Epub 2020 Mar 12. PMID: 32173625

Oxytocin is the main neuropeptide regulating sociality and is expressed in neurons exclusively localized in the hypothalamus. Abnormalities in oxytocin signaling are associated with neurodevelopmental disorders such as autism. Oxytocin plays a role in the early development of neurons and participates in synapse formation. Binding of oxytocin to its receptors in some neuronal cells triggers calcium related pathways leading to enhanced expression of cytoskeletal proteins associated with neurite elongation. Activation of oxytocin receptors regulates the expression of synaptic cell-adhesion molecules. Oxytocin-producing cells appear during the early phase of brain development and their maturation, particularly their ability to produce oxytocin, may influence the formation of neural circuits, and oxytocin receptors play a role in hippocampal neurogenesis. The developing brain undergoes major neurogenesis and synaptogenesis during the first postnatal week of life. The expression of the synaptic proteins during development coincides with periods of functional synapse maturation. Cell adhesion molecules – neurexins and neuroligins are important for the synapse formation.

This study examined the role of oxytocin in regulating the of expression of selected cell-adhesion molecules and scaffolding proteins in the hippocampus in early rat development. Oxytocin administration altered pre and post-synaptic proteins as well as proliferation of neuronal cells. Pre-synaptic proteins showed decreased expression of Synapsin I at the gene and protein levels in response to oxytocin. Synapsin I is one of the most abundant brain phosphoproteins localized at pre-synaptic terminals, cell bodies, and neuronal growth cones. Changes in post-synaptic proteins included the neuroligins as well as other synaptic scaffolding proteins and cell-adhesion molecules. In addition, oxytocin stimulated the proliferation of cells in regions of the hypothalamus. These observations add support to the key role of oxytocin in early brain developmental and synaptogenesis and potentially in the etiology of neurodevelopmental disorders such as autism.