TOR1A is the most common inherited form of dystonia with still unclear pathophysiology and reduced penetrance of 30-40%. ∆ETorA rats mimic the TOR1A disease by expression of the human TOR1A mutation without presenting a dystonic phenotype. We aimed to induce dystonia-like symptoms in male ∆ETorA rats by peripheral nerve injury and to identify central mechanism of dystonia development. Dystonia-like movements (DLM) were assessed using the tail suspension test and implementing a pipeline of deep learning applications. Neuron numbers of striatal parvalbumin+, nNOS+, calretinin+, ChAT+ interneurons and Nissl+ cells were estimated by unbiased stereology. Striatal dopaminergic metabolism was analyzed via in vivo microdialysis, qPCR and western blot. Local field potentials (LFP) were recorded from the central motor network. Deep brain stimulation (DBS) of the entopeduncular nucleus (EP) was performed. Nerve-injured ∆ETorA rats developed long-lasting DLM over 12 weeks. No changes in striatal structure were observed. Dystonic-like ∆ETorA rats presented a higher striatal dopaminergic turnover and stimulus-induced elevation of dopamine efflux compared to the control groups. Higher LFP theta power in the EP of dystonic-like ∆ETorA compared to wt rats was recorded. Chronic EP-DBS over 3 weeks led to improvement of DLM. Our data emphasizes the role of environmental factors in TOR1A symptomatogenesis. LFP analyses indicate that the pathologically enhanced theta power is a physiomarker of DLM. This TOR1A model replicates key features of the human TOR1A pathology on multiple biological levels and is therefore suited for further analysis of dystonia pathomechanism.

Dystonia is a neurological movement disorder characterized by sustained or intermittent involuntary muscle contractions. Loss-of-function mutations in the GNAL gene have been identified to be the cause of "isolated" dystonia DYT25. The GNAL gene encodes for the guanine nucleotide-binding protein G(olf) subunit alpha (Gαolf), which is mainly expressed in the olfactory bulb and the striatum and functions as a modulator during neurotransmission coupling with D1R and A2AR. Previously, heterozygous Gαolf -deficient mice (Gnal+/-) have been generated and showed a mild phenotype at basal condition. In contrast, homozygous deletion of Gnal in mice (Gnal-/-) resulted in a significantly reduced survival rate. In this study, using the CRISPR-Cas9 system we generated and characterized heterozygous Gnal knockout rats (Gnal+/-) with a 13 base pair deletion in the first exon of the rat Gnal splicing variant 2, a major isoform in both human and rat striatum. Gnal+/- rats showed early-onset phenotypes associated with impaired dopamine transmission, including reduction in locomotor activity, deficits in rotarod performance and an abnormal motor skill learning ability. At cellular and molecular level, we found down-regulated Arc expression, increased cell surface distribution of AMPA receptors, and the loss of D2R-dependent corticostriatal long-term depression (LTD) in Gnal+/- rats. Based on the evidence that D2R activity is normally inhibited by adenosine A2ARs, co-localized on the same population of striatal neurons, we show that blockade of A2ARs restores physiological LTD. This animal model may be a valuable tool for investigating Gαolf function and finding a suitable treatment for dystonia associated with deficient dopamine transmission.