Pergolide improvement in neuroleptic-resistant Tourette cases: various mechanisms causing tics

The objective was to report the possibility that in Tourette's disorder (TD) the same pathways may not be involved in all patients. Tics in three children affected with TD showed no improvement after treatment with several neuroleptic drugs (D2 blockers) at appropriate doses. However, they did improve greatly and persistently with pergolide treatment. One of the 3 patients showed a less usual tic feature, the most relevant of which resembled violent myoclonias of both upper limbs. This suggests that in these patients the improvement due to pergolide is not linked to an effect on D2-receptors-carrying GABAergic neurons, as usually assumed, because the patients did not respond to neuroleptics acting in this way. In these 3 cases, unlike in other TD patents, a prevalent action of pergolide by pre-synaptic inhibition of dopamine release on D1-receptors-carrying GABAergic neurons is suggested. Therefore, direct and indirect pathways could be differentially involved in different cases of TD.