Altered dopaminergic regulation of the dorsal striatum is able to induce tic-like movements in juvenile rats

PLoS One. 2018 Apr 26;13(4):e0196515. doi: 10.1371/journal.pone.0196515. eCollection 2018.

Abstract

Motor tics are sudden, repetitive, involuntary movements representing the hallmark behaviors of the neurodevelopmental disease Tourette's syndrome (TS). The primary cause of TS remains unclear. The initial observation that dopaminergic antagonists alleviate tics led to the development of a dopaminergic theory of TS etiology which is supported by post mortem and in vivo studies indicating that non-physiological activation of the striatum could generate tics. The striatum controls movement execution through the balanced activity of dopamine receptor D1 and D2-expressing medium spiny neurons of the direct and indirect pathway, respectively. Different neurotransmitters can activate or repress striatal activity and among them, dopamine plays a major role. In this study we introduced a chronic dopaminergic alteration in juvenile rats, in order to modify the delicate balance between direct and indirect pathway. This manipulation was done in the dorsal striatum, that had been associated with tic-like movements generation in animal models. The results were movements resembling tics, which were categorized and scored according to a newly developed rating scale and were reduced by clonidine and riluzole treatment. Finally, post mortem analyses revealed altered RNA expression of dopaminergic receptors D1 and D2, suggesting an imbalanced dopaminergic regulation of medium spiny neuron activity as being causally related to the observed phenotype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Corpus Striatum / drug effects
  • Corpus Striatum / metabolism*
  • Corpus Striatum / pathology
  • Disease Models, Animal
  • Dopamine Agonists / pharmacology
  • Down-Regulation / drug effects
  • Haloperidol / pharmacology
  • Male
  • Motor Activity / drug effects
  • Oxidopamine / pharmacology
  • Phenotype
  • Quinpirole / pharmacology
  • Rats
  • Rats, Wistar
  • Receptors, Dopamine D1 / genetics
  • Receptors, Dopamine D1 / metabolism
  • Receptors, Dopamine D2 / genetics
  • Receptors, Dopamine D2 / metabolism
  • Tourette Syndrome / physiopathology*

Substances

  • Dopamine Agonists
  • Receptors, Dopamine D1
  • Receptors, Dopamine D2
  • Quinpirole
  • Oxidopamine
  • Haloperidol

Grants and funding

This project received funding from the European Community’s Seventh Framework Programme TS-EUROTRAIN (FP7-PEOPLE-2012- ITN, Grant Agr. No. 316978, recipient BH). Boehringer Ingelheim Pharma GmbH& Co. provided support in the form of salary for author BH, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.