Dystonia is a
movement disorder, characterized by involuntary muscle contractions resulting in
abnormal movements and/or postures. Antidystonic effects of
benzodiazepines in patients with different types of
dystonia could be replicated in the dtsz mutant hamster, a phenotypic model of
paroxysmal dystonia. Compounds with preferred binding at specific subunits of the
gamma aminobutyric acid type A (GABAA) receptor may provide a more beneficial spectrum of effects in comparison with
benzodiazepines. We therefore examined the effects of the α1β3γ2 GABAA receptor preferring compound
zolpidem (2.0-10.0mg/kg i.p.) and of the α2β3γ2 GABAA receptor preferring compound
NS11394 (3.0-30mg/kg i.p.) on the severity of
dystonia in the dtsz mutant in comparison with the
benzodiazepine clonazepam (0.5-1.0mg/kg i.p.). As expected,
clonazepam exerted pronounced antidystonic effects. While
zolpidem showed moderate beneficial effects,
NS11394 significantly increased the severity of
dystonia. The present results indicate for the first time that positive GABAA receptor modulators show contrary effects on
dystonia dependent on their preference for alpha-subunits. The potential link between alterations in GABAA receptor subunits and GABAergic disinhibition in
dystonia deserves further attention in research on the pathophysiology and therapeutic targets.