GABA Receptors & Autism Spectrum Disorders

Sneha Ingle -

Autism spectrum disorder (ASD) is a developmental disorder generally characterized by hindered social interactions. Hypersensitivity and motor impairments are often symptoms of the illness.

The potential causes of ASDs remain elusive, though the scientific evidence clearly shows no link between vaccines and autism.

There is, however, mounting evidence that a neurotransmitter, gamma-amino butyric acid (GABA), may play a role in the disease. GABA is a crucial inhib-
itory neurotransmitter primarily responsible for the regulation of excitatory signals within the nervous system. Imagine it as a policeman, checking the cars and preventing unwanted excitatory signals from reaching the next dendrite.

Recent Imaging studies have shown decreased levels of GABA in brain regions associated with motor control and sound processing in children with Autism. Because GABA is inhibitory in nature, decreased levels suggests an increased excitatory response to stimuli [1]. This model could explain why children with Autism, unable to regulate incoming signals, are often hypersensitive to noises and have motor impairments.

Furthermore, genetic association analysis suggest that defects in genes coding for certain GABA receptors are associated with the disorder [2]. Specific ASDs, such as Rett syndrome, have defects of proteins involved in the GABAergic pathway. In animal models, minute changes in the GABAergic signaling pathway produces Autism-like behaviors [3]. It is not unreasonable therefore, to further investigate such pathways in humans.

References

  1. Agenor Limon, Jorge M. Reyes-Ruiz and Ricardo Miledi (2011). GABA and Glutamate Receptors of the Autistic Brain, Autism - A Neurodevelopmental Journey from Genes to Behaviour, Dr. Valsamma Eapen (Ed.), ISBN:978-953-307-493-1, InTech.
  2. Gaetz, W, et al."GABA Estimation in the Brains of Children on the Autism Spectrum: Measurement Precision and Regional Cortical Variation." NCBI. U.S. National Library of Medicine, 2013. Web.
  3. Cardin, Jessica. "Role of GABA Interneurons in a Genetic Model of Autism." Simons Foundation Autism Research Initiative. SFARI, 2013. Web.
  4. Blumberg, S, et al. “Changes in Prevalence of Parent-reported Autism Spectrum Disorder in School-aged U.S. Children: 2007 to 2011–2012.” National Health Statistics Report. March 20, 2013.