Why Oxytocin Therapy May be Important for ASD? 99
[61–64]. Therefore, if oxytocin administered intranasally can penetrate the
brain, it may be able to improve social information processing. Alternatively,
oxytocin release may be stimulated through melanocortin receptor activation,
which has been shown to increase adult social bonding in prairie voles [62,63].
Overall, targeting the oxytocin system may be an effective mechanism for
improving social cognition.
Why Oxytocin Therapy May be Important for ASD?
Oxytocin, the main neuropeptide of social communications, is expressed in
neurons exclusively localized in the hypothalamus. Numerous neuroendo-
crine, metabolic, autonomic and behavioral effects of oxytocin have been
reported over the last decade. In the rush to find treatments for syndromes
such as autism, many clinical trials have been initiated evaluating oxytocin in
adults, adolescents, and children. However, the impact of oxytocin on the
developing brain, especially on the embryonic and early postnatal maturation
of oxytocin neurons, has been poorly investigated. One of the most important
points to understand is that oxytocin secretion in humans starts just after
birth. Before this, during fetal development the oxytocin receptors develop in
various parts of the brain, as shown in Figure 4.1.
In the following section we will first summarize the available literature on
the oxytocin and AVP neuropeptides and their receptors. Most importantly,
we will address how and why oxytocin is important in human social develop-
ment and in the human fetus where oxytocin and oxytocin receptor positive
neurons emerge. We will also consider why it may be important to treat ASD
infants with nasal oxytocin. The differentiation of oxytocin‐secreting neu-
rons during fetal development and afterwards will be explored and we will
provide evidence that early alterations, from birth, in the central oxytocin
system can lead to severe neurodevelopmental diseases, including feeding
deficit in infancy and severe defects in social behavior in adulthood, as
described in ASD. Our review presents a hypothesis about developmental
dynamics of central oxytocin pathways, which are essential for survival
immediately after birth and for the acquisition of social skills later. A better
understanding of the embryonic and neonatal maturation of the oxytocin
system may lead to better oxytocin based treatments in autism and other
social–behavioral conditions.
An important consideration when comparing developmental trajectories in
translational medicine approaches is that the neurodevelopmental stage of
the human brain at birth corresponds to the rat and mouse brain at postnatal
day 10 [10]. Consistently, the human infant pattern of oxytocin receptor
expression is achieved before birth while, in the rat, oxytocin receptor expres-
sion is achieved around postnatal day 10, and, in mice, between postnatal day 7
