Possible anti-oxidant and neuroprotective mechanisms of zolpidem in attenuating typical anti-psychotic-induced orofacial dyskinesia: a biochemical and neurochemical study

Successful treatment of cranial dystonia using a Zolpidem+Melatonin combination: A video case-series

INTRODUCTION

Cranial dystonias (CrD) are challenging to treat. Oral pharmacotherapy is often sub-optimal, while delicate anatomy and limited availability of skilled botulinum toxin injectors makes this approach risky, and often difficult to access; neurosurgical options e.g. deep brain stimulation, are high-risk in the elderly populations most affected. We observed significant improvement in CrD in 2 patients prescribed Zolpidem+Melatonin combination treatment for insomnia, and therefore trialled this treatment in a further 4 patients with CrD.

METHODS

Six patients were treated with Zolpidem+Melatonin. Pre- and post-treatment videotaped clinical examinations were blindly rated by an independent assessor (EM) and scored using the 'Facial and Oral Movements' section of the abnormal involuntary movements scale (AIMS), as well as the Jankovic rating scale for blepharospasm.

RESULTS

Dystonic features, as measured by the abnormal involuntary movements scale (AIMS) improved by an average of 75% after treatment (6.5±3.1 before treatment to 1.7 +/- 0.8 after treatment). Improvements were also observed in blepharospasm severity scores, and in cervical dystonic features.

CONCLUSION

Zolpidem+Melatonin combination treatment represents a safe and effective treatment for CrD. Low cost and wide availability makes it an attractive option, particularly in resource-constrained healthcare settings, or in patients who have failed, or lack access to alternatives.

Bacillus Calmette-Guérin Vaccine Attenuates Haloperidol-Induced TD-like Behavioral and Neurochemical Alteration in Experimental Rats

Tardive dyskinesia (TD) is a hyperkinetic movement disorder that displays unusual involuntary movement along with orofacial dysfunction. It is predominantly associated with the long-term use of antipsychotic medications, particularly typical or first-generation antipsychotic drugs such as haloperidol. Oxidative stress, mitochondrial dysfunction, neuroinflammation, and apoptosis are major pathophysiological mechanisms of TD. The BCG vaccine has been reported to suppress inflammation, oxidative stress, and apoptosis and exert neuroprotection via several mechanisms. Our study aimed to confirm the neuroprotective effect of the BCG vaccine against haloperidol-induced TD-like symptoms in rats. The rats were given haloperidol (1 mg/kg, i.p.) for 21 days after 1 h single administration of the BCG vaccine (2 × 107 cfu). Various behavioral parameters for orofacial dyskinesia and locomotor activity were assessed on the 14th and 21st days after haloperidol injection. On the 22nd day, all rats were euthanized, and the striatum was isolated to estimate the biochemical, apoptotic, inflammatory, and neurotransmitter levels. The administration of the BCG vaccine reversed orofacial dyskinesia and improved motor function in regard to haloperidol-induced TD-like symptoms in rats. The BCG vaccine also enhanced the levels of antioxidant enzymes (SOD, GSH) and reduced prooxidants (MDA, nitrite) and pro-apoptotic markers (Cas-3, Cas-6, Cas-9) in rat brains. Besides this, BCG treatment also restored the neurotransmitter (DA, NE, 5-HT) levels and decreased the levels of HVA in the striatum. The study findings suggest that the BCG vaccine has antioxidant, antiapoptotic, and neuromodulatory properties that could be relevant in the management of TD.

Protein glycosylation in urine as a biomarker of diseases

Human body fluids have become an indispensable resource for clinical research, diagnosis and prognosis. Urine is widely used to discover disease-specific glycoprotein biomarkers because of its recurrently non-invasive collection and disease-indicating properties. While urine is an unstable fluid in that its composition changes with ingested nutrients and further as it is excreted through micturition, urinary proteins are more stable and their abnormal glycosylation is associated with diseases. It is known that aberrant glycosylation can define tumor malignancy and indicate disease initiation and progression. However, a thorough and translational survey of urinary glycosylation in diseases has not been performed. In this article, we evaluate the clinical applications of urine, introduce methods for urine glycosylation analysis, and discuss urine glycoprotein biomarkers. We emphasize the importance of mining urinary glycoproteins and searching for disease-specific glycosylation in various diseases (including cancer, neurodegenerative diseases, diabetes, and viral infections). With advances in mass spectrometry-based glycomics/glycoproteomics/glycopeptidomics, characterization of disease-specific glycosylation will optimistically lead to the discovery of disease-related urinary biomarkers with better sensitivity and specificity in the near future.

Urinary Biomarkers for Neurodegenerative Diseases

Global incidence of neurodegenerative diseases (NDDs) such as Alzheimer's disease (AD) and Parkinson's disease (PD) is rapidly increasing, but the diagnosis of these diseases at their early stage is challenging. Therefore, the availability of reproducible and reliable biomarkers to diagnose such diseases is more critical than ever. In addition, biomarkers could be used not only to diagnose diseases but also to monitor the development of disease therapeutics. Urine is an excellent biofluid that can be utilized as a source of biomarker to diagnose not only several renal diseases but also other diseases because of its abundance in invasive sampling. However, urine was conventionally regarded as inappropriate as a source of biomarker for neurodegenerative diseases because it is anatomically distant from the central nervous system (CNS), a major pathologic site of NDD, in comparison to other biofluids such as cerebrospinal fluid (CSF) and plasma. However, recent studies have suggested that urine could be utilized as a source of NDD biomarker if an appropriate marker is predetermined by metabolomic and proteomic approaches in urine and other samples. In this review, we summarize such studies related to NDD.

Management of Tardive Syndrome: Medications and Surgical Treatments

Tardive syndrome (TS) is an iatrogenic, often persistent movement disorder caused by drugs that block dopamine receptors. It has a broad phenotype including movement (orobuccolingual stereotypy, dystonia, tics, and others) and nonmotor features (akathisia and pain). TS has garnered increased attention of late because of the Food and Drug Administration approval of the first therapeutic agents developed specifically for this purpose. This paper will begin with a discussion on pathogenesis, clinical features, and epidemiology. However, the main focus will be treatment options currently available for TS including a suggested algorithm based on current evidence. Recently, there have been significant advances in TS therapy, particularly with the development of 2 new vesicular monoamine transporter type 2 inhibitors for TS and with new data on the efficacy of deep brain stimulation. The discussion will start with switching antipsychotics and the use of clozapine monotherapy which, despite the lack of higher-level evidence, should be considered for the treatment of psychosis and TS. Anti-dyskinetic drugs are separated into 3 tiers: 1) vesicular monoamine transporter type 2 inhibitors, which have level A evidence, are approved for use in TS and are recommended first-choice agents; 2) drugs with lower level of evidence for efficacy including clonazepam, Ginkgo biloba, and amantadine; and 3) drugs that have the potential to be beneficial, but currently have insufficient evidence including levetiracetam, piracetam, vitamin B6, melatonin, baclofen, propranolol, zolpidem, and zonisamide. Finally, the roles of botulinum toxin and surgical therapy will be examined. Current therapies, though improved, are symptomatic. Next steps should focus on the prevention and reversal of the pathogenic process.

A unifying theory for the pathoetiologic mechanism of tardive dyskinesia

INTRODUCTION

Chronic treatment with dopamine D2 receptor antagonists has been proposed to lead to dopamine receptor supersensitivity. Frequently, this is conceptualized as upregulation or changes in the structure or function of the post-synaptic D2 receptor. However, the measured 1.4-fold increase in D2 receptor density and the lack of actual receptor supersensitivity are probably inadequate to explain outcomes such as tardive dyskinesia (TD) and dopamine supersensitivity psychosis.

HYPOTHESIS

Recent data suggest that TD may result from a combination of presynaptic, synaptic, and postsynaptic changes.

DISCUSSION

Presynaptic increase in dopamine release occurs when super-therapeutic blockade of postsynaptic D2 receptors results in excess synaptic unbound dopamine which ultimately ends up being reuptaken by the presynaptic neuron through the dopamine transporter. The increased availability of recycled dopamine results in higher vesicular dopamine concentrations. Since the quantity of neurotransmitter released (known as quanta) is determined by the number of presynaptic neurotransmitter vesicles, the increase in the number (concentration) of dopamine molecules in the vesicles results in a higher concentration of synaptic dopamine with successive depolarization events. Synaptic changes such as the appearance of perforated synapses which is an early step in new synapse formation have been shown in animal models of TD. Finally, postsynaptic increases in D2 receptor expression without demonstration of increased sensitivity or potency has been demonstrated.

CONCLUSION

TD likely develops due to changes across the synapse and terminology such as 'dopamine receptor supersensitivity' can be misleading. 'Synaptic upregulation' may be a more correct term.

The antioxidant and neuroprotective effects of Zolpidem on acrylamide-induced neurotoxicity using Wistar rat primary neuronal cortical culture

Zolpidem is an introduced medication for the therapy of sleeping disorders. Its pharmacological effects are consequently characterized by a quick onset and a half-life of 2.4 h. Previous studies revealed the antioxidant and neuroprotectant effects of zolpidem. In this research, we wanted to demonstrate the exact sub-cellular/molecular mechanism of this medication using the primary neuronal cortical culture. For this purpose, firstly, the cortical neurons were isolated from the postnatal Wistar rat pups. Thereafter, different neural toxicity endpoints caused by acrylamide including ROS formation, lipid peroxidation, mitochondrial membrane potential collapse, lysosomal membrane integrity, and apoptosis were determined. All of these parameters are upstream events of cellular apoptosis which justifies neurodegeneration involved in many diseases such as Alzheimer's and Parkinson's. Our results demonstrated that zolpidem at concentrations of 1 and 2 mM prevented all the acrylamide-induced above referenced neural toxic events leading to neuronal apoptosis. These results revealed that zolpidem has the antioxidant and neuroprotectant properties that make it a promising prophylactic agent for preventing neurodegenerative complications. Considering the important role of oxidative stress in the development or progression of diseases, if the medication used as a treatment of a disease has antioxidant properties at the same time, it will certainly have much greater healing effects.

Coumarin analogue 3-methyl-7H-furo[3,2-g] chromen-7-one as a possible antiparkinsonian agent

Introduction:

Parkinson’s disease is the second most common neurodegenerative disease. Monoamine oxidase B inhibitors are used in the treatment of this disease concomitantly with levodopa or as monotherapy. Several substituted coumarins have shown activity as inhibitors of monoamine oxidase B.

Objective:

To evaluate the possible antiparkinsonian effects of the coumarin analogue FCS005 (3-methyl-7H-furo[3,2-g]chromen-7-one) in mouse models, as well as its inhibitory activity towards monoamine oxidases (MAO) and its antioxidant activity.

Materials and methods:

FCS005 was synthesized and the reversal of hypokinesia was evaluated in the reserpine and levodopa models. Moreover, in the haloperidol model, its anticataleptic effects were evaluated. Additionally, the monoamine oxidase inhibitory activity and antioxidant activity of FCS005 were evaluated using in vitro and ex vivo studies, respectively.

Results:

FCS005 (100 mg/kg) caused the reversal of hypokinesia in the reserpine and levodopa models. This furocoumarin also presented anti-cataleptic effects at the same dose. Besides, it showed selective inhibitory activity towards the MAO-B isoform and antioxidant activity.

Conclusion:

These results attribute interesting properties to the compound FCS005. It is important to continue research on this molecule considering that it could be a potential antiparkinsonian agent.

Psychiatric Disorders and Oxidative Injury: Antioxidant Effects of Zolpidem Therapy disclosed In Silico

Zolpidem (N,N-Dimethyl-2-[6-methyl-2-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]acetamide) is a well-known drug for the treatment of sleeping disorders. Recent literature reports on positive effects of zolpidem therapy on improving renal damage after cisplatin and on reducing akinesia without sleep induction. This has been ascribed to the antioxidant and neuroprotective capacity of this molecule, and tentatively explained according to a generic structural similarity between zolpidem and melatonin. In this work, we investigate in silico the antioxidant potential of zolpidem as scavenger of five ROSs, acting via hydrogen atom transfer (HAT) mechanism; computational methodologies based on density functional theory are employed. For completeness, the analysis is extended to six metabolites. Thermodynamic and kinetic results disclose that indeed zolpidem is an efficient radical scavenger, similarly to melatonin and Trolox, supporting the biomedical evidence that the antioxidant potential of zolpidem therapy may have a beneficial effect against oxidative injury, which is emerging as an important etiopathogenesis in numerous severe diseases, including psychiatric disorders.

Effects of agmatine on chlorpromazine-induced neuronal injury in rat

This study was aimed to study the potentially beneficial effects of agmatine on oxidative/nitrosative stress development in the brain of Wistar rats during subacute chlorpromazine treatment. The animals were divided into control (0.9% saline), chlorpromazine (38.7 mg/kg b.w.), chlorpromazine+agmatine (agmatine 75 mg/kg b.w. immediately after chlorpromazine, 38.7 mg/kg b.w. i.p.) and agmatine (75 mg/kg b.w.) groups. All the tested substances were administered intraperitoneally for 15 consecutive days and the rats were sacrificed by decapitation on day 15. Subacute administration of chlorpromazine resulted in increased lipid peroxidation, nitric oxide concentration and superoxide anion production, while completely damaging the antioxidant defence system in the cerebral cortex, striatum, and hippocampus. However, the combined treatment with chlorpromazine and agmatine significantly attenuated the oxidative/nitrosative stress indices and restored the antioxidant capacity to the control values in all of the examined brain regions. Western blot analysis supported biochemical findings in all groups, but the most notable changes were found in the hippocampus. Our results suggest potentially beneficial effects of agmatine, which may be useful in the modified antioxidant approach in chlorpromazine-therapy.

Access to the CNS: Biomarker Strategies for Dopaminergic Treatments

Despite substantial research carried out over the last decades, it remains difficult to understand the wide range of pharmacological effects of dopaminergic agents. The dopaminergic system is involved in several neurological disorders, such as Parkinson's disease and schizophrenia. This complex system features multiple pathways implicated in emotion and cognition, psychomotor functions and endocrine control through activation of G protein-coupled dopamine receptors. This review focuses on the system-wide effects of dopaminergic agents on the multiple biochemical and endocrine pathways, in particular the biomarkers (i.e., indicators of a pharmacological process) that reflect these effects. Dopaminergic treatments developed over the last decades were found to be associated with numerous biochemical pathways in the brain, including the norepinephrine and the kynurenine pathway. Additionally, they have shown to affect peripheral systems, for example the hypothalamus-pituitary-adrenal (HPA) axis. Dopaminergic agents thus have a complex and broad pharmacological profile, rendering drug development challenging. Considering the complex system-wide pharmacological profile of dopaminergic agents, this review underlines the needs for systems pharmacology studies that include: i) proteomics and metabolomics analysis; ii) longitudinal data evaluation and mathematical modeling; iii) pharmacokinetics-based interpretation of drug effects; iv) simultaneous biomarker evaluation in the brain, the cerebrospinal fluid (CSF) and plasma; and v) specific attention to condition-dependent (e.g., disease) pharmacology. Such approach is considered essential to increase our understanding of central nervous system (CNS) drug effects and substantially improve CNS drug development.

Effect of zolpidem on functional recovery in a rat model of ischemic stroke

Objective

To evaluate the effects of zolpidem on functional recovery in a rat model of acute ischemic stroke.

Methods

Following ischemic stroke procedures, 42 rats (six in each group) were randomly assigned to receive zolpidem (0.1, 0.25, 0.5, 1.0, 2.0 or 4.0 mg/kg) or normal saline administer intraperitoneally once daily for two weeks. Motor behavioural index (MBI) scores, radial 8-arm maze (RAM) test times and brain MRI scans were obtained 24 hours (Day 1) and two weeks (Day 14) post-procedure. Immunohistochemistry was performed on Day 14.

Results

By comparison with the normal saline group, the 0.5 and 1.0 mg/kg zolpidem groups showed statistically significant improvements in MBI scores and increased numbers of brain-derived neurotrophic factor (BDNF) stained cells over the two week dosing period. By contrast, the 4.0 mg/kg zolpidem group had statistically significantly impaired MBI scores compared with the control group. No differences among groups were found in RAM times or infarction volumes.

Conclusions

This study in a rat model showed that 0.5–1.0 mg/kg of zolpidem had beneficial effects on behavioural recovery by enhancing neural plasticity without causing any memory impairment in acute ischemic stroke.

Antioxidant effects of rice bran oil mitigate repeated haloperidol-induced tardive dyskinesia in male rats

Tardive dyskinesia (TD) is associated with the use of antipsychotic drugs such as D2 antagonist haloperidol (HP). The chronic use of HP is involved in the causation of free radicals and/or oxidative stress. In view of the nootropic, anti-anxiety, anti-inflammatory-like effects of rice bran oil (RBO) in a variety of investigations, we assessed the protective properties of RBO on HP-induced TD and neurochemical alteration. Rats treated with HP orally at a dose of 0.2 mg/kg/day for a period of 5 weeks developed VCMs which increased progressively as the treatment continued for 5 weeks. Co-administration of RBO by oral tubes at a dose of 0.4 ml/day prevented the induction of HP-induced VCMs. Repeated administration of HP increases the turnover of dopamine metabolism in the striatum. Conversely animals treated with HP + RBO decrease the metabolism of DA than water + HP treated animals. Striatal, malondieldehyde (MDA), hydrogen peroxide (H₂O₂) and antioxidant enzyme superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were also determined. It is suggested that beneficial role of RBO in attenuation of HP-induced TD. The results therefore recommended that supplementation of RBO may be useful in the HP-induced TD. The findings have also potential implication in the treatment of schizophrenia and motor disorders.

Can a Positive Allosteric Modulation of GABAergic Receptors Improve Motor Symptoms in Patients with Parkinson's Disease? The Potential Role of Zolpidem in the Treatment of Parkinson's Disease

At present, patients with advanced Parkinson's disease (PD) are unsatisfactorily controlled by currently used anti-Parkinsonian dopaminergic drugs. Various studies suggest that therapeutic strategies based on nondopaminergic drugs might be helpful in PD. Zolpidem, an imidazopyridine widely used as sleep inducer, shows high affinity only for GABA_A receptors containing the α-1 subunit and facilitates GABAergic neurotransmission through a positive allosteric modulation of GABA_A receptors. Various observations, although preliminary, consistently suggest that in PD patients zolpidem may induce beneficial (and sometimes remarkable) effects on motor symptoms even after single doses and may also improve dyskinesias. Since a high density of zolpidem binding sites is in the two main output structures of the basal ganglia which are abnormally overactive in PD (internal globus pallidus, GPi, and substantia nigra pars reticulata, SNr), it was hypothesized that in PD patients zolpidem may induce through GABA_A receptors an inhibition of GPi and SNr (and, possibly, of the subthalamic nucleus also), resulting in an increased activity of motor cortical areas (such as supplementary motor area), which may give rise to improvement of motor symptoms of PD. Randomized clinical trials are needed in order to assess the efficacy, safety, and tolerability of zolpidem in treating motor symptoms of PD.

Beneficial effects of lycopene against haloperidol induced orofacial dyskinesia in rats: Possible neurotransmitters and neuroinflammation modulation

Tardive Dyskinesia is a severe side effect of chronic neuroleptic treatment consisting of abnormal involuntary movements, characterized by orofacial dyskinesia. The study was designed to investigate the protective effect of lycopene against haloperidol induced orofacial dyskinesia possibly by neurochemical and neuroinflammatory modulation in rats. Rats were administered with haloperidol (1mg/kg, i.p for 21 days) to induce orofacial dyskinesia. Lycopene (5 and 10mg/kg, p.o) was given daily 1hour before haloperidol treatment for 21 days. Behavioral observations (vacuous chewing movements, tongue protrusions, facial jerking, rotarod activity, grip strength, narrow beam walking) were assessed on 0th, 7th(,) 14th(,) 21st day after haloperidol treatment. On 22nd day, animals were killed and striatum was excised for estimation of biochemical parameters (malondialdehyde, nitrite and endogenous enzyme (GSH), pro-inflammatory cytokines [Tumor necrosis factor, Interleukin 1β, Interleukin 6] and neurotransmitters level (dopamine, serotonin, nor epinephrine, 5-Hydroxyindole acetic acid (5-HIAA), Homovanillic acid, 3,4- dihydroxyphenylacetic acid. Haloperidol treatment for 21 days impaired muscle co-ordination, motor activity and grip strength with an increased in orofacial dyskinetic movements. Further free radical generation increases MDA and nitrite levels, decreasing GSH levels in striatum. Neuroinflammatory markers were significantly increased with decrease in neurotransmitters levels. Lycopene (5 and 10mg/kg, p.o) treatment along with haloperidol significantly attenuated impairment in behavioral, biochemical, neurochemical and neuroinflammatory markers. Results of the present study attributed the therapeutic potential of lycopene in the treatment (prevented or delayed) of typical antipsychotic induced orofacial dyskinesia.

Tardive dyskinesia (syndrome): Current concept and modern approaches to its management

Tardive dyskinesia is a serious, disabling and potentially permanent, neurological hyperkinetic movement disorder that occurs after months or years of taking psychotropic drugs. The pathophysiology of tardive dyskinesia is complex, multifactorial and still not fully understood. A number of drugs were tried for the management of this motor disturbance, yet until now no effective and standard treatment has been found. It is very disappointing to realize that the introduction of antipsychotics from the second generation has not significantly decreased the prevalence and incidence of tardive dyskinesia. Therefore, the management of this motor disturbance remains an actual topic as well as a challenge for clinicians. This review summarizes recent relevant publications concerning the treatment of tardive dyskinesia.

Oxidative stress and the antipsychotic-induced vacuous chewing movement model of tardive dyskinesia: evidence for antioxidant-based prevention strategies

RATIONALE

Despite decades of research, tardive dyskinesia (TD) remains a poorly understood iatrogenic movement disorder with few effective treatments and no known cure. Accordingly, the development of an innocuous strategy to prevent or mitigate antipsychotic (AP)-associated TD would represent an important clinical advance. Supporting evidence for antioxidant (AX)-based treatment regimens can be found in the preclinical literature, where AP-induced vacuous chewing movements (VCMs) in rats are attenuated by the concurrent administration of direct and indirect AXs.

OBJECTIVES

Our aim was to review the preclinical literature examining the role of AX-promoting treatments in the prevention of AP-induced VCMs in rats.

METHODS

A literature search using Google Scholar and PubMed was performed. Relevant results were qualitatively reviewed.

RESULTS

Studies featuring a variety of naturally occurring and synthetic AX treatments were identified and included in the review. The majority of studies used haloperidol (HAL), a typical AP, to induce VCMs. Studies revealed reduced VCMs in co-treated rats, with favorable changes seen in markers of oxidative stress (OS) and AX status, but were limited by their short durations.

CONCLUSIONS

Some preclinical evidence suggests that the inclusion of a naturally occurring and benign AX compound as an adjunct to AP treatment may help guard patients against TD, but additional long-duration studies are needed. This AX-based strategy is further substantiated by accumulating evidence of preexisting OS abnormalities in schizophrenia (SZ).

An animal model to study the molecular basis of tardive dyskinesia

Long-term treatment with haloperidol is associated with a number of extrapyramidal side effects. This limitation presents a marked therapeutic challenge. The present method (21 days administration of haloperidol, 5 mg/kg, i.p.) has been established to gain deeper insight into the molecular etiology (inflammation and apoptosis) of haloperidol-induced cellular death. In the present model, besides the corresponding increase in the vacuous chewing movements (VCMs), enhanced oxidative stress, there was a significant increase in cellular markers of inflammation and apoptotic protein (caspase-3), leading to cellular death. We also suggest that this model will be effective in preclinical testing of new chemical entities for the treatment of haloperidol induced tardive dyskinesia and related symptoms.

Motor symptoms of schizophrenia: is tardive dyskinesia a symptom or side effect? A modern treatment

Abnormal involuntary dyskinetic movements in schizophrenia patients have been documented for more than 140 years. Clinicians should distinguish between two kinds of disturbances-spontaneous dyskinetic movements and movements induced by psychotropic medications-which may look familiar clinically. As a modern term, tardive dyskinesia (TD) is a potentially permanent neurological hyperkinetic movement disorder that occurs after months or years of taking psychotropic drugs. Several distinct forms of TD exist, specifically tardive akathisia, tardive blepharospasm, tardive dystonia, tardive gait, tardive myoclonus, tardive tremor, and tardive tics, and they have different pathophysiologies and treatment. The pathogenesis of TD remains unclear, and the pathophysiology is complex and multifactorial. Moreover, there is solid evidence of a genetic predisposition to TD. This article summarizes recent relevant publications concerning TD and the most recent studies regarding treatment of this disorder with antioxidative agents.

Differential striatal levels of TNF-alpha, NFkappaB p65 subunit and dopamine with chronic typical and atypical neuroleptic treatment: role in orofacial dyskinesia

Long term use of typical neuroleptics such as haloperidol may be limited by unwanted motor side effects like tardive dyskinesia characterized by repetitive involuntary movements, involving the mouth, face and trunk. Atypical neuroleptics, such as clozapine and risperidone are devoid of these side effects. However the precise mechanisms of the neuronal toxicity induced by haloperidol are poorly understood. It is possible that typical and atypical antipsychotic differently affects neuronal survival and death and that these effects considerably contribute to the differences in the development of TD. The aim of the present study is to investigate the role of TNF-alpha and NFkappaB on the toxicity induced by chronic haloperidol administration in an animal model of tardive dyskinesia. Rats were treated for 21 days with: haloperidol (5 mg/kg), clozapine (5 and 10 mg/kg), risperidone (5 mg/kg) or saline. Orofacial dyskinetic movements and total locomotor activity was evaluated. Striatal levels of dopamine were measure by HPLC/ED whereas striatal levels of TNF-alpha and NFkappaB p65 subunit were measured by ELISA technique. Haloperidol increased orofacial dyskinetic movements and total locomotor activity (on day 22) (P<or=0.05). Clozapine and risperidone also increased the orofacial dyskinetic movements but that significantly less than haloperidol (P<or=0.05). Differential effect of haloperidol and atypical neuroleptics on striatal dopamine levels and striatal levels of TNF-alpha and NFkappaB p65 subunit was found out. Haloperidol significantly decreased the striatal dopamine levels whereas clozapine and risperidone did not. Haloperidol but not clozapine and risperidone significantly increased the levels of TNF-alpha and NFkappaB p65 subunit (P<or=0.05). The present study suggests the impossible involvement of striatal TNF-alpha and NFkappaB p65 subunit in haloperidol-induced orofacial dyskinesia in rats, an animal model for human tardive dyskinesia.

Modulatory effect of neurosteroids in haloperidol-induced vacuous chewing movements and related behaviors

RATIONALE

Tardive dyskinesia is a syndrome of abnormal and involuntary movements which occurs as a complication of long-term neuroleptic therapy especially classical neuroleptics such as haloperidol and chlorpromazine. Dysfunction of GABA receptor mediated inhibition, and increased glutamatergic neurotransmission has been implicated in the development of orofacial dyskinesia in rats and tardive dyskinesia in humans. Neurosteroids modulate both GABAergic as well as glutamatergic neurotransmission in various brain areas.

OBJECTIVE

The objective of the present study was to elucidate the role of various neurosteroids in neuroleptic-induced vacuous chewing movements and related behaviors in rats by using behavioral, biochemical, and neurochemical parameters.

MATERIALS AND METHODS

Animals chronically treated with haloperidol (1 mg/kg i.p.) for a period of 21 days exhibited marked increase in vacuous chewing movements, tongue protrusions, and facial jerkings as compared to vehicle-treated controls. It also resulted in increased superoxide anion levels and lipid peroxidation, whereas decreased levels of endogenous antioxidant enzymes (catalase and superoxide dismutase) in rat brain striatum homogenates. Neurochemical studies revealed that chronic administration of haloperidol resulted in significant decrease in the levels of dopamine, serotonin, and norepinephrine in rat brain striatum homogenates, whereas urine biogenic amines metabolite levels were increased. In a series of experiments, rats co-administered with allopregnanolone (0.5, 1, and 2 mg/kg i.p.) and progesterone (5, 10, and 20 mg/kg i.p.), both positive GABA-modulating [negative N-methyl-D-aspartate (NMDA)-modulating] neurosteroids prevented, whereas pregnenolone (0.5, 1, and 2 mg/kg i.p.) and dihydroxyepiandrosterone sulfate (0.5, 1, and 2 mg/kg i.p.) both negative GABA-modulating (positive NMDA-modulating) neurosteroids aggravated all the behavioral, biochemical, and neurochemical parameters.

CONCLUSIONS

These results suggest that neurosteroids may play a significant role in the pathophysiology of vacuous chewing movements and related behaviors by virtue of their action on either the GABA or NMDA modulation. Furthermore, neurosteroids showing selectivity for positive GABA modulation and/or negative NMDA modulation may be particularly efficacious as novel therapeutic agents for the treatment of tardive dyskinesia and deserve further evaluation.