Brain Chemistry

A peptide is a chain of amino acids joined together by peptide bonds. Many peptides produced by cells of the brain serve as neurotransmitters, neuromodulators or hormones. Proteins are long peptides.

Oxytocin

Oxytocin is a neuropeptide that is involved in social functions such as attachment and bonding. Oxytocin receptor fields are labile (there are shifts in receptor density occurring in early development). A failure to shift from an infantile to a mature pattern may underlie autism. 30 autistic children were found to have lowered levels of plasma oxytocin in comparison to normals. This leads to the possibility that exposure to exogenous oxytocin (petocin) at time of delivery (in patients who are genetically susceptible) may cross the placenta and blood brain barrier and cause down regulation of oxytocin receptors in the brain of the fetus, or even cause and immune response to oxytocin receptors.

Vasoactive Intestinal Peptide, Calcitonin-related gene peptide, Brain-derived neurotrophic factor and Neurotrophin 4

Elevated Levels of Neuropeptides/Neurotrophins in Youngsters with Autism
Population	Percent with Elevated Neuropeptides & Neurotrophins
Autism	96.9%
Mental Retardation	92.4%
Cerebral Palsy	9.2%
Healthy Children (Controls)	0

• Most children diagnosed with Autism or Mental Retardation had concentrations of 2 of more of the measured neuropeptides or neurotrophins in peripheral blood at birth, while only few children with CP and no control child did.
• Neuropeptides and neurotrophins measured include vasoactive intestinal peptide, calcitonin related gene peptide, brain derived neurotrophic factor, and neurtrophin 4.

In April 2000, scientists (Dr. Karin Nelson, National Institute of Neurological Disorders and Stroke) discovered what they believe may be biological markers in the blood of newborn infants who later develop autism and mental retardation.

In their study, eight proteins were targeted that play a role in the development of the brain. Blood samples (which were drawn at birth and saved by the California Birth Defects Monitoring Program) for healthy children as well as children who had later been diagnosed with autism, mental retardation and cerebral palsy were studied.

The study showed that most children with autism or mental retardation had exceedingly high concentrations of 2 or more or the measured neuropeptides or neurotrophins in their blood during the earliest days of life while few of the cerebral palsy and none of the healthy children did.

This study implies that a genetic component to autism and mental retardation exists and that it may be possible to devise a test which would allow identification of these markers at birth. If we become able to identify children who have these high concentrations of proteins at birth, we may consider them high risk and therefore protect them from environmental factors which may exacerbate the condition resulting in autism.