Ataxia Research Articles

New ways to repurpose salmeterol in an animal model of fibromyalgia.

Fibromyalgia (FM) is a syndrome of pervasive chronic pain accompanied by low mood, sleep disorders, and cognitive decline. The dysfunction of central pain processing systems along with neurotransmitter disturbances are possible contributing mechanisms. Genetic polymorphism of the 𝛽2 adrenergic receptors is reported in FM patients. It is reported that chronic β2 agonists administration is effective for neuropathic pain alleviation. No current information, however, exists on their potential to alleviate nociplastic pain, such as FM. Therefore, the purpose of the current study is to examine salmeterol's potential antiallodynic effects in experimentally produced FM and explore some of the possible contributing mechanisms. Thirty rats are allocated into three groups (n = 10): a normal group, a reserpine group that received reserpine (1 mg/kg; s.c.) for 3 days, and a reserpine + salmeterol group that received salmeterol (1 mg/kg; i.p.) for 21 consecutive days following last reserpine injection. Reserpine administration resulted in behavioral and biochemical changes consistent with FM, including thermal and mechanical hyperalgesia, depressive behavior, and motor incoordination. This is coupled with disturbed spinal monoamine levels, depressed cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling, disturbed mitochondrial function/dynamics, and compromised blood-nerve barrier integrity. Treatment with salmeterol conceivably reversed these effects. β2 receptor agonists such as salmeterol could be regarded as a promising strategy for the management of FM.

Uniparental IsoDisomy: a case study on a new mechanism of Friedreich ataxia.

Friedreich's Ataxia (FRDA) is the most common hereditary ataxia and is mainly caused by biallelic GAA repeat expansion in the FXN gene. Rare patients carrying FXN point mutations or intragenic deletions are reported. We describe the first FRDA patient with a chromosome 9 segmental Uniparental isoDisomy (UPiD) unmasking a homozygous FXN expansion initially undetected by TP-PCR. The child presented with a progressive proprioceptive ataxia associated with peripheral sensory neuronopathy and severe scoliosis. Whole genome sequencing (WGS) identified a maternal segmental Uniparental Isodisomy (UPiD) encompassing FXN. Short tandem repeats analysis on WGS showed a biallelic FXN expansion. The identification of a deletion in the primer-annealing region of the TP-PCR explained the initial TP-PCR failure. This is the first documented case of FRDA caused by segmental UPiD. This case highlights the complexity of the molecular diagnosis of FRDA, and emphasises the importance of integrating results from various technical diagnostic approaches.

Extracellular Vesicles from Mesenchymal Stem Cells Reverse Neuroinflammation and Restore Motor Coordination in Hyperammonemic Rats.

Cirrhotic patients may show minimal hepatic encephalopathy (MHE), with mild cognitive impairment and motor deficits. Hyperammonemia and inflammation are the main contributors to the cognitive and motor alterations of MHE. Hyperammonemic rats reproduce these alterations. There are no specific treatments for the neurological alterations of MHE. Extracellular vesicles from mesenchymal stem cells (MSC-EVs) are promising to treat inflammatory and immune diseases. We aimed to assess whether treatment of hyperammonemic rats with MSC-EVs reduced neuroinflammation in cerebellum and restored motor coordination and to study the mechanisms involved. The effects of MSC-EVs were studied in vivo by intravenous injection to hyperammonemic rats and ex vivo in cerebellar slices. Motor coordination was analyzed using the beam walking test. Effects on neuroinflammation were assessed by immunohistochemistry, immunofluorescence and Western blot. Injection of MSC-EVs reduced microglia and astrocytes activation in cerebellum and restored motor coordination in hyperammonemic rats. Ex vivo experiments show that MSC-EVs normalize pro-inflammatory factors, including TNFα, NF-kB activation and the activation of two key pathways leading to motor incoordination (TNFR1-NF-kB-glutaminase-GAT3 and TNFR1-CCL2-BDNF-TrkB-KCC2). TGFβ in the EVs was necessary for these beneficial effects. MSC-EVs treatment reverse neuroinflammation in the cerebellum of hyperammonemic rats and the underlying mechanisms leading to motor incoordination. Therapy with MSC-EVs may be useful to improve motor function in patients with MHE.

Differences in the Impact of Intensive Rehabilitation on Hereditary Ataxias and the Cerebellar Subtype of Multiple System Atrophy.

Multiple system atrophy-cerebellar type (MSA-C) exhibits faster disease progression than does hereditary spinocerebellar degeneration (hSCD). In this study, we aimed to investigate the differences in the treatment effects and sustainability of intensive rehabilitation between patients with hSCD and those with MSA-C. Forty-nine patients (hSCD = 30, MSA-C = 19) underwent a 2- or 4-week intensive rehabilitation program. Balance function was evaluated using the scale for the assessment and rating of ataxia (SARA) and the balance evaluation systems test (BESTest) at pre-intervention, post-intervention, and 6-month follow-up. Notably, both groups demonstrated beneficial effects from the rehabilitation intervention. However, differences were observed in the magnitude and duration of these effects. In the hSCD group, the SARA scores at follow-up remained similar to those at baseline, indicating sustained benefits. However, the MSA-C group showed some deterioration in SARA scores compared with baseline scores but maintained improvements on the BESTest, demonstrating partial sustainability. Differences, mainly in sustainability, were observed between the hSCD and MSA-C groups. This may be due to varying rates of symptom progression. The findings of this study are significant when considering the frequency of follow-ups based on disease type.

Self-assessed use and provision of assistive devices in individuals with hereditary ataxia at the interface between development in childhood and adolescence and symptom progression

Assistive devices are essential in neuropediatrics, but the database on the self-assessed use by and supply of medical aids to those affected with hereditary ataxia is small. The present work aims to examine the individual perspective of those affected by the use and supply of aids and to discuss them in the field of tension between physiological and psychosocial development and symptom progression. The research project represents a cooperation with the German Heredo-Ataxia-Society following the "patients as partners in research" approach. The data was collected via online questionnaires and focus group surveys and analyzed quantitatively and qualitatively using a mixed methodological approach. Based on the present sample of affected adolescents and adults (n=47 online questionnaires, n=6 focus group surveys), a fundamentally positive assessment of the use of medical aids was evident. In contrast, for the individual evaluation of access and supply of assistive devices, four main problems were identified, some of which can be extrapolated to other diagnoses but amplified in children and adolescents due to the low prevalence of hereditary ataxia. Especially in these age groups, the lengthy process leading up to the diagnosis and the associated gap in the indication for assistive devices poses a serious problem. Moreover, there is lack of evidence for justifying prescription of age-group-specific assistive devices. In addition to the necessity of improvement in the care process, there are significant gaps in the knowledge about an association between self-confidence and coping with the disease, on the one hand, and the acceptance of aids, on the other, in children and adolescents with rare diseases characterized by symptom progression. In addition, there is an urgent need to improve the evidence base for specific tools, especially their importance for promoting independence according to age and developmental phase.

Treatment of neurologic pathology and inflammation in Machado-Joseph disease through in vivo self-assembled siRNA.

Machado-Joseph disease, also known as Spinocerebellar ataxia type 3 (MJD/SCA3), is a fatal autosomal dominant hereditary ataxia characterized by cerebellar ataxia resulting from the abnormal expansion of CAG repeats in exon 10 of the ATXN3 gene. Presently, there is no effective treatment for SCA3. Small interfering RNAs (siRNAs) are emerging as potential therapeutic strategies to specifically target the disease-causing mutant ATXN3 (mATXN3) protein. However, the delivery efficiency of siRNAs remains a major obstacle for clinical application, particularly in brain disorders. This study aimed to develop a synthetic biology strategy to reprogram the host liver as a tissue chassis to induce and deliver in vivo self-assembled siRNAs (IVSA-siRNAs) to target the ATXN3 gene. A synthetic construct directed by a cytomegalovirus promoter was designed to encode a neuron-targeting rabies virus glycoprotein tag and mATXN3-siRNA. After intravenous injection, the synthetic construct was taken up by mouse livers, which were then reprogrammed to enable the self-assembly, production, and secretion of small extracellular vesicles (sEVs) encapsulating mATXN3-siRNA. The sEV-encapsulated mATXN3-siRNA was further transported through the endogenous circulating system of sEVs, crossing the blood-brain barrier and reaching the cerebellar cortex and spinal cerebellar tract, where they silenced the ATXN3 gene. Treatment with the synthetic construct for 8 or 12 weeks led to significant improvements in motor balance ability and reduction of cerebellar atrophy in YACMJD84.2 transgenic mice. The number of Purkinje cells in the cerebellar cortex was significantly increased, and the loss of myelin basic protein was reduced. Moreover, the quantity of neurotoxic nuclear inclusion bodies and the expression of glial fibrillary acidic protein, which promotes neuroinflammation in activated astrocytes, were decreased significantly. The synthetic construct facilitated the generation and delivery of IVSA-siRNA to the cerebellar cortex and spinal cerebellar tract, thereby inhibiting the expression of mATXN3 protein. This treatment successfully addressed motor impairments, alleviated neuropathological phenotypes, and mitigated neuroinflammation in YACMJD84.2 transgenic mice. Our strategy effectively overcomes the primary challenges associated with siRNA therapy for cerebellar ataxia, offering a promising avenue for future clinical treatments.

Investigating the genetic basis of hereditary spastic paraplegia and cerebellar Ataxia in Pakistani families

BackgroundHereditary Spastic Paraplegias (HSPs) and Hereditary Cerebellar Ataxias (HCAs) are progressive neurodegenerative disorders encompassing a spectrum of neurogenetic conditions with significant overlaps of clinical features. Spastic ataxias are a group of conditions that have features of both cerebellar ataxia and spasticity, and these conditions are frequently clinically challenging to distinguish. Accurate genetic diagnosis is crucial but challenging, particularly in resource-limited settings. This study aims to investigate the genetic basis of HSPs and HCAs in Pakistani families.MethodsFamilies from Khyber Pakhtunkhwa with at least two members showing HSP or HCA phenotypes, and who had not previously been analyzed genetically, were included. Families were referred for genetic analysis by local neurologists based on the proband’s clinical features and signs of a potential genetic neurodegenerative disorder. Whole Exome Sequencing (WES) and Sanger sequencing were then used to identify and validate genetic variants, and to analyze variant segregation within families to determine inheritance patterns. The mean age of onset and standard deviation were calculated to assess variability among affected individuals, and the success rate was compared with literature reports using differences in proportions and Cohen’s h.ResultsPathogenic variants associated with these conditions were identified in five of eight families, segregating according to autosomal recessive inheritance. These variants included previously reported SACS c.2182 C > T, p.(Arg728*), FA2H c.159_176del, p.(Arg53_Ile58del) and SPG11 c.2146 C > T, p.(Gln716*) variants, and two previously unreported variants in SACS c.2229del, p.(Phe743Leufs*8) and ZFYVE26 c.1926_1941del, p.(Tyr643Metfs*2). Additionally, FA2H and SPG11 variants were found to have recurrent occurrences, suggesting a potential founder effect within the Pakistani population. Onset age among affected individuals ranged from 1 to 14 years (M = 6.23, SD = 3.96). The diagnostic success rate was 62.5%, with moderate effect sizes compared to previous studies.ConclusionsThe findings of this study expand the genotypic and phenotypic spectrum of HSPs and HCAs in Pakistan and emphasize the importance of utilizing exome/genome sequencing for accurate diagnosis or support accurate differential diagnosis. This approach can improve genetic counseling and clinical management, addressing the challenges of diagnosing neurodegenerative disorders in resource-limited settings.

A Novel MAG Variant Causes Hereditary Spastic Paraplegia in a Consanguineous Pakistani Family.

Background and objectives: Hereditary spastic paraplegia (HSP) is characterized by unsteady gait, motor incoordination, speech impairment, abnormal eye movement, progressive spasticity and lower limb weakness. Spastic paraplegia 75 (SPG75) results from a mutation in the gene that encodes myelin associated glycoprotein (MAG). Only a limited number of MAG variants associated with SPG75 in families of European, Middle Eastern, North African, Turkish and Palestinian ancestry have been documented so far. This study aims to provide further insight into the clinical and molecular manifestations of HSP. Methods: Using whole-exome sequencing, we investigated a consanguineous Pakistani family where three individuals presented with clinical signs of HSP. Sanger sequencing was used to carry out segregation analysis on available family members, and a minigene splicing assay was utilized to evaluate the effect of the splicing variant. Results: We identified a novel homozygous pathogenic splice donor variant in MAG (c.46 + 1G > T) associated with SPG75. RNA analysis revealed exon skipping that resulted in the loss of a start codon for ENST00000361922.8 isoform. Affected individuals exhibited variable combinations of nystagmus, developmental delay, cognitive impairments, spasticity, dysarthria, delayed gait and ataxia. The proband displayed a quadrupedal stride, and his siblings experienced frequent falls and ataxic gait as one of the prominent features that have not been previously reported in SPG75. Conclusions: Thus, the present study presents an uncommon manifestation of SPG75, the first from the Pakistani population, and broadens the spectrum of MAG variants.

Clinical, Radiological and Pathological Features of a Large American Cohort of Spinocerebellar Ataxia (SCA27B).

Spinocerebellar ataxia 27B due to GAA repeat expansions in the fibroblast growth factor 14 (FGF14) gene has recently been recognized as a common cause of late-onset hereditary cerebellar ataxia. Here we present the first report of this disease in the US population, characterizing its clinical manifestations, disease progression, pathological abnormalities, and response to 4-aminopyridine in a cohort of 102 patients bearing GAA repeat expansions. We compiled a series of patients with SCA27B, recruited from 5 academic centers across the United States. Clinical manifestations and patient demographics were collected retrospectively from clinical records in an unblinded approach using a standardized form. Post-mortem analysis was done on 4 brains of patients with genetically confirmed SCA27B. In our cohort of 102 patients with SCA27B, we found that SCA27B was a late-onset (57 ± 12.5 years) slowly progressive ataxia with an episodic component in 51% of patients. Balance and gait impairment were almost always present at disease onset. The principal finding on post-mortem examination of 4 brain specimens was loss of Purkinje neurons that was most severe in the vermis most particularly in the anterior vermis. Similar to European populations, a high percent of patients 21/28 (75%) reported a positive treatment response with 4-aminopyridine. Our study further estimates prevalence and further expands the clinical, imaging and pathological features of SCA27B, while looking at treatment response, disease progression, and survival in patients with this disease. Testing for SCA27B should be considered in all undiagnosed ataxia patients, especially those with episodic onset. ANN NEUROL 2024.

Efficacy and safety of riluzole for treating motor function in rare dyskinesia syndromes: a systematic review with meta-analysis.

We conducted a systematic review and meta-analysis to evaluate the clinical effectiveness and safety of riluzole to treat neurodegenerative dyskinesia in patients, using the Cochrane collaboration guidelines. We searched databases including Medline, Embase, and Cochrane without any language filters. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was used as a guideline, and the study protocol was registered in PROSPERO (CRD42022354627). Eleven studies involving 1376 patients were included. There was a significant overall effect of riluzole on changes in motor function scores. However, the level of heterogeneity was I2 = 74%. In the subgroup analyses, there were no significant effects of riluzole on motor scores in hereditary ataxia, Parkinson's disease, or Huntington's disease. In the sensitivity analysis, there were no significant effects of riluzole on motor function scores. Furthermore, there were no significant differences in adverse events between the riluzole and placebo groups. Although riluzole may not have significant efficacy for improving motor function in neurodegenerative dyskinesia syndromes compared with placebo, it seems to have an acceptable safety profile. Moreover, it may be effective for hereditary ataxia syndromes, although there was a relatively small effect size and limited quality of evidence.

A novel mutation in SETX and ATM causes ataxia in consanguineous Pakistani families.

Ataxia is usually caused by cerebellar pathology or a decrease in vestibular or proprioceptive afferent input to the cerebellum. It is characterized by uncoordinated walking, truncal instability, body or head tremors, uncontrolled coordination of the hands, dysarthria, and aberrant eye movements. The objective of the current investigation was to identify the underlying genetic cause of the hereditary ataxia that affects the Pakistani population. We studied numerous consanguineous Pakistani families whose members had ataxia-related clinical symptoms to varying degrees. The families were chosen from the Punjab province, and the neurophysician conducted a clinical examination. Peripheral blood samples from both sick and healthy members of the family were taken after obtaining informed consent. Genomic DNA was used to find potential variations in probands using whole exome sequencing. The study was carried out at the University Hospital of Tübingen, Germany, and Government College University in Faisalabad, Pakistan, during 2018-2023. The molecular analysis of these families identified different variants including SGCB: c.902C>T, c.668G>A, ATM: c.6196_6197insGAA, SPG11: c.5769del, SETX c.5525_5533del, and ATM: c.7969A>T. A noteworthy mutation in ATM and SETX was observed among them, and its symptoms were shown to cause ataxia in these families. The current study broadens the mutation spectrum of several hereditary ataxia types and suggests the next generation sequencing in conjunction with clinical research for a more accurate diagnosis of overlapping phenotypes of this disorder in the Pakistani population.

Stimulation of central histaminergic transmission attenuates diazepam-induced motor disturbance on rota-rod and beam walking tests in mice.

Diazepam administration has been shown to influence the release of histamine in various brain areas involved in motor behavior. Therefore, the present study explored the plausible regulatory role of the central histaminergic system in diazepam-induced deficits in motor performance in mice using the rota-rod and beam walking tests. In this study, several doses of diazepam (0.5, 1, 2, and 3 mg/kg, i.p.) were assessed in mice for changes in motor performance on the rota-rod and beam walking test. In addition, the brain histamine levels were determined after diazepam administration, and the diazepam-induced motor deficits were assessed in mice, pretreated centrally (intracerebroventricular) with histaminergic agents such as histamine (0.1, 10 µg), histamine precursor (L-histidine: 0.1, 2.5 µg), histamine neuronal releaser/H 3 receptor antagonist (thioperamide: 0.5, 10 µg), H 1 and H 2 receptor agonist [2-(3-trifluoromethylphenyl) histamine (FMPH: 0.1, 6.5 µg; amthamine: 0.1, 5 µg)/antagonist (H 1 : cetirizine 0.1 µg) and (H 2 : ranitidine: 50 µg)]. Results indicate that mice treated with diazepam at doses 1, 2 mg/kg, i.p. significantly increased the brain histamine levels. Moreover, in mice pretreated with histaminergic transmission-enhancing agents, the diazepam (2 mg/kg, i.p.)-induced motor incoordination was significantly reversed. Contrastingly, diazepam (1 mg/kg, i.p.) in its subeffective dose produced significant motor deficits in mice preintracerebroventricular injected with histamine H 1 and H 2 receptor antagonists on both the employed tests. Therefore, it is postulated that endogenous histamine operates via H 1 and H 2 receptor activation to alleviate the motor-impairing effects of diazepam.

Cerebellar cognitive affective syndrome and vertebrobasilar ischemia. From cerebello-cerebral diaschisis to "dysmetria of thought"

Cerebellum, along with it' s role in coordinating motor functions, exercises a significant regulatory influence in fields of cognitive and affective functions. Therefore, studying the effect of cerebrovascular atherosclerotic pathology on mood and cognition should not be limited to stenotic dysfunctions of carotid arteries, but also extend its methodological framework to the consideration of the integrity of vertebrobasilar system (VBS), cerebellar perfusion and posterior cerebral circulation in general, as it has not been yet sufficiently addressed whether VBS insufficiency is associated with deterioration of patients' mental and emotional status and quality of life (QoL). Vertebrobasilar circulatory dysfunction has been pointed out, since decades, as a cause of progressive memory impairment and dementia, due to multiple infarcts in cerebral areas which are topographically critical for mental and emotional functions. Indicative of the pathophysiological and anatomic-functional association of VBS with these neuro-psychiatric domains are cerebellar cognitive-affective syndrome (CCAS) and crossed cerebello-cerebral diaschisis (CCCD). Mental and psychiatric components of CCAS, along with ataxic motor disability, constitute the conceptual hypothesis of "dysmetry of thought", while diagnostic significance of mental dysfunctions and psychopathological manifestations, in terms of symptoms preceding motor impairments that ascribe cerebellar malfunction in the epicenter of their pathophysiology, such as cerebellar ataxias, in which, early recognition of CCAS may facilitate therapeutic interventions aimed at improving QoL, reveal that cerebellar pathology, either of degenerative etiology or vascular substrate on the ground of vertebrobasilar insufficiency (VBI) or other surgical conditions of the posterior fossa, is associated with deterioration of patients' QoL which is related to significant impairments in their cognitive functions with (co)manifested emotional disorders. Studies in animal models also support these conclusions. Since VBI is responsible for a wide range of psychiatric and neurological symptoms, new findings concurred with current indications advocating that, without consideration of VBS disorders, it is impossible to clarify the connection of cerebral perfusion dysfunctions to neurocognitive deficits. The inclusion of cerebellar perfusion disorders in scientific research and clinical approaches to cognitive and affective disorders that may occur in patients with cerebrovascular lesions constitutes a paradigm of best clinical practices implementation and interdisciplinary convergence of neurosciences and vascular medicine.

Genetic investigation of patients with autosomal recessive ataxia and identification of two novel variants in the SQSTM1 and SYNE1 genes

Hereditary ataxias are classified by inheritance patterns into autosomal dominant, autosomal recessive, X-linked, and mitochondrial modes of inheritance. A large group of adult hereditary ataxias have autosomal dominant inheritance, and autosomal recessive cerebellar ataxias (ARCAs) are rare, with greater diversity in phenotypic and genotypic features. Therefore, comprehensive genetic testing is useful for identifying the genes responsible for ARCAs. We identified two novel pathogenic variants of the SQSTM1 and SYNE1 genes via whole-exome sequencing in patients with ARCAs.

Ablation of TrkB from Enkephalinergic Precursor-Derived Cerebellar Granule Cells Generates Ataxia.

In ataxia disorders, motor incoordination (ataxia) is primarily linked to the dysfunction and degeneration of cerebellar Purkinje cells (PCs). In spinocerebellar ataxia 6 (SCA6), for example, decreased BDNF-TrkB signalling appears to contribute to PC dysfunction and ataxia. However, abnormal BDNF-TrkB signalling in granule cells (GCs) may contribute to PC dysfunction and incoordination in ataxia disorders, as TrkB receptors are also present in GCs that provide extensive input to PCs. This study investigated whether dysfunctional BDNF-TrkB signalling restricted to a specific subset of cerebellar GCs can generate ataxia in mice. To address this question, our research focused on TrkbPenk-KO mice, in which the TrkB receptor was removed from enkephalinergic precursor-derived cerebellar GCs. We found that deleting Ntrk2, encoding the TrkB receptor, eventually interfered with PC function, leading to ataxia symptoms in the TrkbPenk-KO mice without affecting their cerebellar morphology or levels of selected synaptic markers. These findings suggest that dysfunctional BDNF-TrkB signalling in a subset of cerebellar GCs alone is sufficient to trigger ataxia symptoms and may contribute to motor incoordination in disorders like SCA6.

The effect of assessor expertise on reliability of analysis of video signs associated with concussion in Australian football

ObjectivesTo determine whether spotters with medical training and experience in managing concussion have higher inter-rater reliability and accuracy than non-medical personnel when identifying video signs associated with concussion in Australian football. DesignRetrospective cohort study. MethodsVideo clips were collected of all impacts potentially resulting in concussion during 2012 and 2013 Australian Football League (AFL) seasons. Raters were divided into medical doctors and a non-medical group comprising allied health practitioners (physiotherapists) and non-medical/non-allied health personnel (performance analysts). Raters assessed 102 randomly selected videos for signs of concussion. The inter-rater reliability was calculated. Sensitivity, specificity, positive and negative predictive values were calculated by comparing the rater responses to the consensus opinion from two highly experienced clinicians with expertise in concussion. ResultsNo statistically significant difference in inter-rater reliability was observed between the medical doctors and the non-medical group. Both groups demonstrated good to excellent agreement for slow to get up, clutching at head/face and facial injury. Both groups displayed intra-class coefficient >0.55 for no protective action-floppy, loss of responsiveness, and motor incoordination, and displayed lowest agreement for no protective action-tonic posturing, impact seizure and blank/vacant look. No statistically significant difference was found between the groups for sensitivity, specificity, positive and negative predictive values for correctly classifying video signs compared to the expert consensus opinion. ConclusionsAfter completing sufficient standardised training and testing, medical and non-medical personnel demonstrate comparable reliability in identifying video signs of concussion in professional Australian football and may be suitable for the role of video spotter.

Effects of voluntary chronic intermittent access to ethanol on the behavioral performance in adult C57BL/6 J mice

BackgroundChronic alcohol drinking increases the risk of alcohol use disorders, causing various neurological disorders. However, the impact of different ethanol levels on a spectrum of behaviors during chronic drinking remains unclear. In this study, we established an intermittent access to ethanol in a two-bottle choice (IA2BC) procedure to explore the dose-dependent effects of ethanol on the behavioral performance of C57BL/6 J mice. MethodsAdult male C57BL/6 J mice were provided voluntary access to different ethanol concentrations (0 %, 5 %, 10 %, and 20 % ethanol) under a 12-week IA2BC paradigm. A battery of behavioral tests was administered to assess alterations in pain threshold, anxiety-like behaviors, locomotor activity, motor coordination, and cognition. Ethanol consumption and preference were monitored during each session. Moreover, the liver, heart, and lung tissues were examined using pathological microscopy. ResultsThe average (standard deviation) ethanol consumption of mice under the IA2BC paradigm increased dose-dependently to 5.1 (0.2), 8.7 (0.7), and 15.9 (0.8) g/kg/24 h with 5 %, 10 %, and 20 % ethanol, respectively. However, there is no significant difference in ethanol preference among all the ethanol groups. Chronic ethanol drinking caused hyperalgesia, cognitive impairment, and motor incoordination, but caused no changes in body temperature, locomotor activity, or anxiety-like behaviors. Minor histopathological alterations in the liver were detected; however, no major abnormal pathology was observed in the heart or lungs. ConclusionThese findings clarify the link between ethanol dosage and behavioral changes in mice over a 12-week IA2BC paradigm, thereby bridging the knowledge gap regarding the effects of chronic ethanol drinking on neurological disorders.

Gastrointestinal disorders in hyperkinetic movement disorders and ataxia

Disorders of the gastrointestinal tract in patients suffering from hypokinetic movement disorders, and in particular Parkinson's disease, have increasingly been the subject of more intensive neuromedical research. So far, few data are available for patients with hyperkinetic movement disorders and ataxias. This review article summarizes the currently available and relevant publications on this topic. The particular focus is on essential tremor, restless legs syndrome, Huntington's disease and the group of hereditary ataxias. Further intensive research will be necessary in the future to collect detailed information also for these disease symptoms about specific disturbance patterns, in order to understand the underlying pathological pathways and to derive specific treatment approaches.

Negative allosteric modulation of CB1 cannabinoid receptor signalling decreases intravenous morphine self-administration and relapse in mice.

The endocannabinoid system interacts with the reward system to modulate responsiveness to natural reinforcers, as well as drugs of abuse. Previous preclinical studies suggested that direct blockade of CB1 cannabinoid receptors (CB1R) could be leveraged as a potential pharmacological approach to treat substance use disorder, but this strategy failed during clinical trials due to severe psychiatric side effects. Alternative strategies have emerged to circumvent the side effects of direct CB1 binding through the development of allosteric modulators. We hypothesized that negative allosteric modulation of CB1R signalling would reduce the reinforcing properties of morphine and decrease behaviours associated with opioid misuse. By employing intravenous self-administration in mice, we studied the effects of GAT358, a functionally-biased CB1R negative allosteric modulator (NAM), on morphine intake, relapse-like behaviour and motivation to work for morphine infusions. GAT358 reduced morphine infusion intake during the maintenance phase of morphine self-administration under a fixed ratio 1 schedule of reinforcement. GAT358 also decreased morphine-seeking behaviour after forced abstinence. Moreover, GAT358 dose dependently decreased the motivation to obtain morphine infusions under a progressive ratio schedule of reinforcement. Strikingly, GAT358 did not affect the motivation to work for food rewards in an identical progressive ratio task, suggesting that the effect of GAT358 in decreasing opioid self-administration was reward specific. Furthermore, GAT58 did not produce motor ataxia in the rotarod test. Our results suggest that CB1R NAMs reduced the reinforcing properties of morphine and could represent a viable therapeutic route to safely decrease misuse of opioids.

Oculomotor and Vestibular Deficits in Friedreich Ataxia - Systematic Review and Meta-Analysis of Quantitative Measurements.

Disease-specific oculomotor assessments play a crucial role in the early diagnosis of hereditary cerebellar ataxias. Whereas several studies have reported on quantitative oculomotor and vestibular measurements in Friedreich's Ataxia (FRDA), the value of specific oculomotor paradigms remains unclear. We aimed to address this knowledge gap through a systematic literature review and providing disease-specific recommendations for a tailored set of eye-movement recordings in FRDA. MEDLINE and Embase were searched for studies reporting on quantitative oculomotor and/or vestibular measurements in FRDA-patients. Data on oculomotor and vestibular parameters were extracted and correlations with a range of clinical parameters were sought. Included studies (n = 17) reported on 185 patients. Abnormalities observed included the presence of saccadic intrusions (143/161) such as square-wave jerks (SWJ, 90/109) and ocular flutter (21/43), impaired eccentric gaze-holding (40/104), abnormal pursuit (81/93) and angular vestibulo-ocular reflex (aVOR) deficits (39/48). For visually-guided saccades (VGS), we frequently observed increases in saccade latency (27/38) and dysmetric saccades (71/93), whereas saccade velocity was more often preserved (37/43). Augmented anti-saccade (AS) latency, downbeat nystagmus and frequent macro-SWJ correlated with disease duration. Increased AS-latency and VGS-latency, frequent macro-SWJ, reduced aVOR-gain and augmented aVOR peak-latency correlated with disease severity. A broad range of oculomotor and vestibular deficits are documented in the literature. Impairments in pursuit, saccades and aVOR-responses are most commonly reported, and as such, should be prioritized as disease markers. Quantitative oculomotor testing in FRDA may facilitate early diagnosis and prove valuable in monitoring disease progression and treatment response.