Correlations between stereotypies in ASD and neurotransmitters: a systematic review

Abstract

Introduction. There is evidence that neurotransmitters and their systems may be involved in the pathophysiology of motor stereotypies in Autism Spectrum Disorder. Objective. Conduct a review to assess evidence on correlations between stereotyped behaviors and changes in neurotransmitter systems, by analyzing original articles in an animal model. Method. Studies published between January 2000 and January 2021 were searched in six databases and 19 reports were selected. Reports' population, method, main results, and conclusions were extracted. Results. The analysis revealed that serotonergic, dopaminergic, glutamatergic, cholinergic, and GABAergic systems were involved in the modulation of stereotypies in animal models of ASD. In general, the administration of antagonists of serotoninergic, glutamatergic, and dopaminergic receptors causes a reduction in stereotyped behavior, and the stimulation of GABAergic and cholinergic systems, through the administration of receptor agonists, was also responsible for reducing these behaviors. There were some discrepancies in the responses depending on the routes of drug administration and the brain areas, suggesting that these factors also influence the pathophysiology of stereotypies in ASD. Conclusion. The reports suggest that the over-activation of serotoninergic, glutamatergic, and dopaminergic systems, as the suppression of GABAergic and cholinergic systems may have a direct influence on the appearance and modulation of stereotypies. Registration: PROSPERO CRD42021235397.