Haloperidol-induced parkinsonism is attenuated by varenicline in mice

Effects of Tiliroside and Lisuride Co-Treatment on the PI3K/Akt Signal Pathway: Modulating Neuroinflammation and Apoptosis in Parkinson's Disease

Researchers are actively exploring potential bioactive compounds to enhance the effectiveness of Lisuride (Lis) in treating Parkinson's disease (PD) over the long term, aiming to mitigate the serious side effects associated with its extended use. A recent study found that combining the dietary flavonoid Tiliroside (Til) with Lis has potential anti-Parkinson's benefits. The study showed significant improvements in PD symptoms induced by 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) when Til and Lis were given together, based on various behavioral tests. This combined treatment significantly improved motor function and protected dopaminergic neurons in rats with PD induced by MPTP. It also activated important molecular pathways related to cell survival and apoptosis control, as indicated by the increased pAkt/Akt ratio. Til and Lis together increased B-cell lymphoma 2 (Bcl-2), decreased caspase 3 activity, and prevented brain cell decay. Co-administration also reduced tumor necrosis factor alpha (TNF-α) and Interleukin-1 (IL-1). Antioxidant markers such as superoxide dismutase (SOD), catalase, and reduced glutathione significantly improved compared to the MPTP-induced control group. This study shows that using Til and Lis together effectively treats MPTP-induced PD in rats, yielding results comparable to an 8 mg/kg dose of levodopa, highlighting their potential as promising Parkinson's treatments.

Neuroprotective potential of Cordia dichotoma in Parkinson's syndrome induced by haloperidol: An animal study

Background

Parkinson's disease (PD) is one of the major neurodegenerative disorders and the prevalence is expected to increase during the next couple of decades. There is a need for safe and effective therapeutic regimen that can effectively manage this neurotoxicity. The leaves and several other parts of Cordia dichotoma are known to possess number of medicinal properties. The purpose of this study was to examine the neuroprotective role of Cordia dichotoma in an experimental model of haloperidol-induced P.D.

Materials and methods

Five groups of rats were randomly assigned into different groups. Intraperitoneal haloperidol 1 mg/kg was given to the inducer group and 0.5% CMC to the normal control. The reference standard was syndopa 10 mg/kg, p.o., and the test group animals received C. dichotoma's ethanolic extract at 200 and 400 mg/kg orally for one week. Rats exposed to haloperidol were assessed for behavioral, neurochemical, and histopathological parameters.

Results

C. dichotoma leaves extract dose-dependently increased behavioral activity and muscle coordination. The extract at 400 mg/kg was found to increase significantly (P < 0.001) the central square activity in open-field test, compared to haloperidol treated rats. In stepping test, both tested doses of C. dichotoma (200 mg and 400 mg/kg) were found to significantly (P < 0.001) reduce akinesia, besides these doses also decreased the catatonic responses induced by haloperidol. Further, the extraction treatment (200 mg and 400 mg/kg) significantly (P < 0.001) decreased malonaldehyde and increased antioxidant enzymes like catalase compared to the control group. Histopathological changes in the test group showed a significant reduction in haloperidol damage to normal morphology in cortical, hippocampus, substantia nigra, and pyramidal.

Conclusion

The observations of the study suggest that Cordia dichotoma attenuated the haloperidol-induced neurological changes, indicating that the plant might benefit in the treatment of Parkinson's disease. The activity of Cordia dichotoma could be linked to its antioxidant property. Since, the drug is traditionally used in different parts of world; it could be a promising agent if more research establishes its safety and efficacy in other experimental models of Parkinson's Disease.

Jobelyn® improves motor dysfunctions induced by haloperidol in mice via neuroprotective mechanisms relating to modulation of cAMP response-element binding protein and mitogen-activated protein kinase

The clinical efficacy of haloperidol in the treatment of psychosis has been limited by its tendency to cause parkinsonian-like motor disturbances such as bradykinesia, muscle rigidity and postural instability. Oxidative stress-evoked neuroinflammation has been implicated as the key neuropathological mechanism by which haloperidol induces loss of dopaminergic neurons and motor dysfunctions. This study was therefore designed to evaluate the effect of Jobelyn® (JB), an antioxidant supplement, on haloperidol-induced motor dysfunctions and underlying molecular mechanisms in male Swiss mice. The animals were distributed into 5 groups (n = 8), and treated orally with distilled water (control), haloperidol (1 mg/kg) alone or in combination with each dose of JB (10, 20 and 40 mg/kg), daily for 14 days. Thereafter, changes in motor functions were evaluated on day 14. Brain biomarkers of oxidative stress, proinflammatory cytokines (tumor necrosis factor-alpha and interleukin-6), cAMP response-element binding protein (CREB), mitogen-activated protein kinase (MAPK) and histomorphological changes were also investigated. Haloperidol induces postural instability, catalepsy and impaired locomotor activity, which were ameliorated by JB. Jobelyn® attenuated haloperidol-induced elevated brain levels of MDA, nitrite, proinflammatory cytokines and also boosted neuronal antioxidant profiles (GSH and catalase) of mice. It also restored the deregulated brain activities of CREB and MAPK, and reduced the histomorphological distortions as well as loss of viable neuronal cells in the striatum and prefrontal cortex of haloperidol-treated mice. These findings suggest possible benefits of JB as adjunctive remedy in mitigating parkinsonian-like adverse effects of haloperidol through modulation of CREB/MAPK activities and oxidative/inflammatory pathways.

Animal models of Parkinson's disease: bridging the gap between disease hallmarks and research questions

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor symptoms. More than 200 years after its first clinical description, PD remains a serious affliction that affects a growing proportion of the population. Prevailing treatments only alleviate symptoms; there is still neither a cure that targets the neurodegenerative processes nor therapies that modify the course of the disease. Over the past decades, several animal models have been developed to study PD. Although no model precisely recapitulates the pathology, they still provide valuable information that contributes to our understanding of the disease and the limitations of our treatment options. This review comprehensively summarizes the different animal models available for Parkinson's research, with a focus on those induced by drugs, neurotoxins, pesticides, genetic alterations, α-synuclein inoculation, and viral vector injections. We highlight their characteristics and ability to reproduce PD-like phenotypes. It is essential to realize that the strengths and weaknesses of each model and the induction technique at our disposal are determined by the research question being asked. Our review, therefore, seeks to better aid researchers by ensuring a concrete discernment of classical and novel animal models in PD research.

Cannabidiol improves haloperidol-induced motor dysfunction in zebrafish: a comparative study with a dopamine activating drug

BACKGROUND

Cannabidiol (CBD) extracted from the cannabis plant is believed to have a medicinal value due to its neuroprotective effect via anti-inflammatory and antioxidant action. Recent behavioral studies in rats have reported that CBD mediates serotonin (5-HT1A) receptor action to improve motor dysfunction induced by dopamine (D2) receptor blockade. In particular, its effect on D2 receptor blockade in the striatum is an important function associated with neurological disorders resulting from various extrapyramidal motor dysfunctions. Dopaminergic neurodegeneration associated with this site is known for inducing Parkinson's disease (PD), which often affects the elderly. It is also known to cause drug-induced Parkinsonism. This study examines the ameliorating effect of CBD, which does not act directly on D2 receptors, against drug-induced motor dysfunction induced by the antipsychotic drug (haloperidol).

METHODS

We created a drug-induced Parkinsonism model in zebrafish larvae using an antipsychotic drug (haloperidol). We evaluated the distance traveled and repetitive light-stimulation response. Furthermore, we examined whether administration of several concentrations of CBD ameliorates symptoms of the Parkinsonism model and compared its effects with those of antiparkinsonian drug ropinirole.

RESULTS

CBD concentrations equal to half of haloperidol's resulted in an almost complete reversal of haloperidol-induced motor dysfunction, as measured by the distance traveled by the zebrafish and their response to light-stimulus. While ropinirole also significantly reversed haloperidol's effects at the same concentration as CBD, CBD was more effective than ropinirole.

CONCLUSIONS

CBD-induced motor dysfunction improvement via D2 receptor blockade is a potential novel mechanism for the treatment of haloperidol-induced motor dysfunction.

Inhibition of Oxidative Stress and the NF-κB Pathway by a Vitamin E Derivative: Pharmacological Approach against Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder. In this study, PD was induced via (ip) injection of haloperidol (1 mg/kg/day). Animals were divided into seven groups (n = 70). Group I received the vehicle carboxymethylcellulose (CMC; 0.5%), group II was treated with designated 1 mg/kg haloperidol, and group III received the standard drug Sinemet (100 mg/kg), while groups IV-VII received a tocopherol derivative (Toco-D) at dose levels of 5, 10, 20, and 40 mg/kg, respectively, via the oral route. All groups received haloperidol for 23 consecutive days after their treatments except the control group. The improvement in locomotor activity and motor coordination was evaluated by using behavioral tests. Oxidative stress markers, neurotransmitters, and monoamine oxidase B (MAO-B) as well as NF-κB levels in the whole brain were measured. mRNA expression analysis of α-synuclein was carried out using the PCR technique. Toco-D at 20 mg/kg showed the maximum improvement in locomotor activity. The levels of antioxidant enzymes and neurotransmitters were also increased by the treatment with Toco-D. Inflammatory cytokine levels and mRNA expression of α-synuclein were decreased by Toco-D in treated animals. This study concluded that Toco-D might be effective in the improvement of locomotor activity and motor coordination in haloperidol-induced PD.

Impact of Gestational Haloperidol Exposure on miR-137-3p and Nr3c1 mRNA Expression in Hippocampus of Offspring Mice

BACKGROUND

Schizophrenia is a mental disorder caused by both environmental and genetic factors. Prenatal exposure to antipsychotics, an environmental factor for the fetal brain, induces apoptotic neurodegeneration and cognitive impairment of offspring similar to schizophrenia. The aim was to investigate molecular biological changes in the fetal hippocampus exposed to haloperidol (HAL) by RNA expression as a model of the disorder.

METHODS

HAL (1 mg/kg/d) was administered to pregnant mice. Upregulated and downregulated gene expressions in the hippocampus of offspring were studied with RNA-sequencing and validated with the qPCR method, and micro-RNA (miR) regulating mRNA expressional changes was predicted by in silico analysis. An in vitro experiment was used to identify the miRNA using a dual-luciferase assay.

RESULTS

There were significant gene expressional changes (1370 upregulated and 1260 downregulated genes) in the HAL group compared with the control group on RNA-sequencing analysis (P &lt; .05 and q &lt; 0.05). Of them, the increase of Nr3c1 mRNA expression was successfully validated, and in silico analysis predicted that microRNA-137-3p (miR-137-3p) possibly regulates that gene's expression. The expression of miR-137-3p in the hippocampus of offspring was significantly decreased in the first generation, but it increased in the second generation. In vitro experiments with Neuro2a cells showed that miR-137-3p inversely regulated Nr3c1 mRNA expression, which was upregulated in the HAL group.

CONCLUSIONS

These findings will be key for understanding the impact of the molecular biological effects of antipsychotics on the fetal brain.

Parkinsonism Attenuation by Antihistamines via Downregulating the Oxidative Stress, Histamine, and Inflammation

Parkinson disease (PD) is a neurodegenerative disorder of the motor activity of the brain, regulated by dopaminergic neurons of substantia nigra, resulting in an increased density of histaminergic fibers. This study was aimed to evaluate the effects of H1 antagonist's ebastine and levocetirizine in PD per se and in combination. Animals were divided into 9 groups (n = 10). Group 1 received carboxymethyl cellulose CMC (1 mL/kg). Group II was treated with haloperidol (1 mg/kg) (diseased group). Group III was treated with levodopa/carbidopa (levo 20 mg/kg). Groups IV and V were treated with ebastine at dose levels of 2 and 4 mg/kg, respectively. Groups VI and VII were treated with levocetirizine at dose levels of 0.5 and 1 mg/kg, respectively. Group VIII was treated with ebastine (4 mg/kg) + levo (20 mg/kg) in combination. Group IX was treated with levocetirizine (1 mg/kg) + levo (20 mg/kg). PD was induced with haloperidol (1 mg/kg iv, once daily for 23 days) for a duration of 30 min. Behavioral tests like rotarod, block and triple horizontal bars, actophotometer, and open field were performed. Biochemical markers of oxidative stress, i.e., SOD, CAT, GSH, MDA, dopamine, serotonin, and nor-adrenaline and nitrite, were determined. Histamine, mRNA expression of α-synuclein, and TNF-α level in the serum and brain of mice were analyzed. Endogenous biochemical markers were increased except mRNA expression of α-synuclein, which was reduced. In combination therapy with the standard drug, ebastine (4 mg/kg) significantly improved the cataleptic state and dopamine levels, but no significant difference in the renal and liver functioning tests was observed. This study concluded that ebastine (4 mg/kg) might work in the treatment of PD as it improves the cataleptic state in haloperidol-induced catalepsy.

Exposure to varenicline protects against locomotor alteration in a MPTP mouse model of Parkinson's disease

The beneficial effects of drugs that act via nicotinic acetylcholine receptors (nAChRs) on Parkinson's disease (PD) symptomatology may explain the negative correlation between cigarette smoking and risk of this neurological condition. Varenicline, an α4β2 nAChR partial agonist approved for smoking cessation treatments, could be valuable for PD treatment. Here, we investigated varenicline effects in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) PD mouse model. From postnatal day (PN) 90 to PN119, male C57BL/6 mice were exposed daily to varenicline (2 mg/kg) by gavage. After that, MPTP was injected (30 mg/kg, ip) once a day for five days. At PN125, locomotor and anxiety-like effects were assessed with the open field test. At PN126, immobile behavior was assessed with the forced swimming test. At PN127, the frontal cerebral cortex was collected to evaluate dopamine and DOPAC levels. To verify whether varenicline was protective during the MPTP insult, a separate group of MPTP animals received varenicline from PN90 to PN124. MPTP reduced cortical dopamine content and increased dopamine turnover. Those effects were not reversed by varenicline treatment. Interestingly, varenicline reversed the MPTP-induced hyperactivity in the open field. Both maintenance of varenicline treatment during MPTP exposure or its interruption before MPTP exposure elicited similar results. No alterations were observed in anxiety-like behavior or in immobility time. Altogether, these findings suggested that varenicline treatment reduced the MPTP-induced hyperactivity, but did not protect against dopaminergic damage. Based on this partial protective effect, varenicline could exert neuroprotective effects on circuits that control motor activity in PD.

Neuroprotective effect of α-pinene self-emulsifying nanoformulation against 6-OHDA induced neurotoxicity on human SH-SY5Y cells and its in vivo validation for anti-Parkinson's effect

Oxidative stress (OS) is involved in the multifaceted pathogenic paradigm of neurodegenerative diseases like Parkinson's disease (PD). Monoterpenes like α-pinene (ALP) is considered to be a therapeutically potent antioxidant agent able to attenuate and scavenge various reactive oxygen species and reactive nitrogen species. The present study aimed to evaluate the in vitro and in vivo neuroprotective effect of α-pinene self-emulsifying nanoformulation (ALP-SENF) for PD. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was done to evaluate the neurotoxic dose of the ALP-SENF; however, the neuroprotective effect was assessed by 6-hydroxydopamine (6-OHDA) induced neurotoxicity model on SH-SY5Y taking NAC (N-acetyl-l-cysteine) as standard. The in vivo anti-Parkinson's activity of the ALP-SENF was compared with that of the plain ALP suspension by using reserpine antagonism and haloperidol-induced Parkinsonism model in rats. Various behavioral tests and biochemical antioxidant enzymes were estimated. The in vitro results revealed that treatment with ALP-SENF at a concentration of 100 and 200 µM was found to show significant neuronal SH-SY5Y cell viability against 50 µM 6-OHDA. ALP-SENF treated animals have seen significant neurobehavioral improvement. Furthermore, the levels of antioxidative enzymes in biochemical test reveals a marked enhancement in the expression of antioxidant enzymes that significantly attenuated the OS induced neurodegeneration. Due to the mechanisms of their antioxidant action, it was probably due to the scavenging of free radicals and the expression of antioxidant enzymes. It also improved neurobehavioral changes induced by reserpine and haloperidol.

Haloperidol-induced catalepsy as an animal model for parkinsonism: A systematic review of experimental studies

Several useful animal models for parkinsonism have been developed so far. Haloperidol-induced catalepsy is often used as a rodent model for the study of motor impairments observed in Parkinson's disease and related disorders and for the screening of potential antiparkinsonian compounds. The objective of this systematic review is to identify publications that used the haloperidol-induced catalepsy model for parkinsonism and to explore the methodological characteristics and the main questions addressed in these studies. A careful systematic search of the literature was carried out by accessing articles in three different databases: Web of Science, PubMed and SCOPUS. The selection and inclusion of studies were performed based on the abstract and, subsequently, on full-text analysis. Data extraction included the objective of the study, study design and outcome of interest. Two hundred and fifty-five articles were included in the review. Publication years ranged from 1981 to 2020. Most studies used the model to explore the effects of potential treatments for parkinsonism. Although the methodological characteristics used are quite varied, most studies used Wistar rats as experimental subjects. The most frequent dose of haloperidol used was 1.0 mg/kg, and the horizontal bar test was the most used to assess catalepsy. The data presented here provide a framework for an evidence-based approach to the design of preclinical research on parkinsonism using the haloperidol-induced catalepsy model. This model has been used routinely and successfully and is likely to continue to play a critical role in the ongoing search for the next generation of therapeutic interventions for parkinsonism.

Appraisal of anti-Parkinson activity of rhinacanthin-C in haloperidol-induced parkinsonism in mice: A mechanistic approach

This study aimed to appraise the anti-Parkinson's potential of rhinacanthin-C (RC). RC (5, 10, and 20 mg/kg) was orally administered for 25 days in albino mice to treat haloperidol-induced parkinsonism (1 mg/kg). RC significantly (p < .05) improved the motor symptoms in block, bar, rotarod, and balance beam walking tests in treated mice. RC reduced the cataleptic effect dose-dependently. The RC therapy notably (p < .001) enhanced reduced glutathione, catalase, and superoxide dismutase levels while decreased malondialdehyde and nitrite levels in the tissue homogenates of the treated mice. The RC therapy significantly (p < .01-.001) restored the dopamine, norepinephrine, and serotonin levels in the brain tissue of treated mice as co-evidenced from brain histology. RC did not adversely affect complete blood count, and liver and kidney function tests. Taken together, these results have shown that RC is effective in treating motor and non-motor symptoms of Parkinson's disease. PRACTICAL APPLICATIONS: Rhinacanthus nasutus is a medicinally rich plant that has folklore use in several ailments. The plant possessed multiple pharmacological activities due to the presence of naphthoquinones. The major compound of this plant rhinacanthin-C was used in the present study to evaluate it's anti-Parkinson's activity. The results provide scientific evidence of the anti-Parkinson's potential of rhinacanthin-C that support the use of R. nasutus leaves in the prevention and treatment of Parkinson's disorder.

Classic and evolving animal models in Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disease with motor and non-motor symptoms. PD is characterized by the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and deficiency of dopamine in the striatal region. The primary objective in PD research is to understand the pathogenesis, targets, and development of therapeutic interventions to control the progress of the disease. The anatomical and physiological resemblances between humans and animals gathered the researcher's attention towards the use of animals in PD research. Due to varying age of onset, symptoms, and progression rate, PD becomes heterogeneous which demands the variety of animal models to study diverse features of the disease. Parkinson is a multifactorial disorder, selection of models become important as not a single model shows all the biochemical features of the disease. Currently, conventional pharmacological, neurotoxin-induced, genetically modified and cellular models are available for PD research, but none of them recapitulate all the biochemical characteristics of the disease. In this review, we included the updated knowledge on the main features of currently available in vivo and in vitro models as well as their strengths and weaknesses.

Pharmacological studies of effort-related decision making using mouse touchscreen procedures: effects of dopamine antagonism do not resemble reinforcer devaluation by removal of food restriction

RATIONALE

Effort-based decision-making tasks offer animals choices between preferred reinforcers that require high effort to obtain vs. low effort/low reward options. The neural mechanisms of effort-based choice are widely studied in rats, and evidence indicates that mesolimbic dopamine (DA) and related neural systems play a key role. Fewer studies of effort-based choice have been performed in mice.

OBJECTIVES

The present studies used touchscreen operant procedures (Bussey-Saksida boxes) to assess effort-based choice in mice.

METHODS

CD1 mice were assessed on a concurrent fixed ratio 1 panel pressing/choice procedure. Mice were allowed to choose between rearing to press an elevated panel on the touchscreen for a preferred food (strawberry milkshake) vs. consuming a concurrently available less preferred alternative (high carbohydrate pellets).

RESULTS

The DA D₂ antagonist haloperidol (0.05-0.15 mg/kg IP) produced a dose-related decrease in panel pressing. Intake of food pellets was not reduced by haloperidol, and in fact, there was a significant quadratic trend, indicating a tendency for pellet intake to increase at low/moderate doses. In contrast, reinforcer devaluation by removing food restriction substantially decreased both panel pressing and pellet intake. In free-feeding choice tests, mice strongly preferred milkshake vs. pellets. Haloperidol did not affect food intake or preference.

CONCLUSION

Haloperidol reduced the tendency to work for food, but this reduction was not due to decreases in primary food motivation or preference. Mouse touchscreen procedures demonstrate effects of haloperidol that are similar but not identical to those shown in rats. These rodent studies may be relevant for understanding motivational dysfunctions in humans.

Emerging neuroprotective effect of metformin in Parkinson's disease: A molecular crosstalk

Parkinson's disease (PD) is a devastating neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and Lewy pathology. PD is a major concern of today's aging population and has emerged as a global health burden. Despite the rapid advances in PD research over the past decades, the gold standard therapy provides only symptomatic relief and fails to halt disease progression. Therefore, exploring novel disease-modifying therapeutic strategies is highly demanded. Metformin, which is currently used as a first-line therapy for type 2 diabetes mellitus (T2DM), has recently demonstrated to exert a neuroprotective role in several neurodegenerative disorders including PD, both in vitro and in vivo. In this review, we explore the neuroprotective potential of metformin based on emerging evidence from pre-clinical and clinical studies. Regarding the underlying molecular mechanisms, metformin has been shown to inhibit α-synuclein (SNCA) phosphorylation and aggregation, prevent mitochondrial dysfunction, attenuate oxidative stress, modulate autophagy mainly via AMP-activated protein kinase (AMPK) activation, as well as prevent neurodegeneration and neuroinflammation. Overall, the neuroprotective effects of metformin in PD pathogenesis present a novel promising therapeutic strategy that might overcome the limitations of current PD treatment.

Determining the pharmacokinetics of nicotinic drugs in the endoplasmic reticulum using biosensors

Nicotine dependence is thought to arise in part because nicotine permeates into the endoplasmic reticulum (ER), where it binds to nicotinic receptors (nAChRs) and begins an "inside-out" pathway that leads to up-regulation of nAChRs on the plasma membrane. However, the dynamics of nicotine entry into the ER are unquantified. Here, we develop a family of genetically encoded fluorescent biosensors for nicotine, termed iNicSnFRs. The iNicSnFRs are fusions between two proteins: a circularly permutated GFP and a periplasmic choline-/betaine-binding protein engineered to bind nicotine. The biosensors iNicSnFR3a and iNicSnFR3b respond to nicotine by increasing fluorescence at [nicotine] <1 µM, the concentration in the plasma and cerebrospinal fluid of a smoker. We target iNicSnFR3 biosensors either to the plasma membrane or to the ER and measure nicotine kinetics in HeLa, SH-SY5Y, N2a, and HEK293 cell lines, as well as mouse hippocampal neurons and human stem cell-derived dopaminergic neurons. In all cell types, we find that nicotine equilibrates in the ER within 10 s (possibly within 1 s) of extracellular application and leaves as rapidly after removal from the extracellular solution. The [nicotine] in the ER is within twofold of the extracellular value. We use these data to run combined pharmacokinetic and pharmacodynamic simulations of human smoking. In the ER, the inside-out pathway begins when nicotine becomes a stabilizing pharmacological chaperone for some nAChR subtypes, even at concentrations as low as ∼10 nM. Such concentrations would persist during the 12 h of a typical smoker's day, continually activating the inside-out pathway by >75%. Reducing nicotine intake by 10-fold decreases activation to ∼20%. iNicSnFR3a and iNicSnFR3b also sense the smoking cessation drug varenicline, revealing that varenicline also permeates into the ER within seconds. Our iNicSnFRs enable optical subcellular pharmacokinetics for nicotine and varenicline during an early event in the inside-out pathway.

Desferrioxamine and dextromethorphan combination exhibited synergistic effect and reversed the catalepsy behaviour in 6-hydroxydopamine hydroydopamine administered rats through regulating brain glutamate levels

OBJECTIVE

To investigate the effect of desferrioxamine (DFO) and dextromethorphan (DXM) combination in animal model of Parkinson's disease (PD).

METHODS

The PD was induced in rats through intracerebroventricular administration of 6-hydroxydopamine (6-OHDA) using stereotaxic apparatus. The animals were subjected to behavioural assessments and neurobiochemicals estimation followed by immunohistochemistry staining of neuron specific enolase (NSE) in striatum.

KEY FINDINGS

Desferrioxamine and DXM combination has significantly reversed the catalepsy behaviour and elevated the antioxidant enzymes (SOD, CAT, GSH) and dopamine levels. Interestingly, the level of glutamate, nitric oxide, cytokines (IL-1β, TNF-α) and NSE expressions were found to be decreased in striatum region of 6-OHDA-administered rats. The combination of DFO and DXM has shown synergism in most of the parameters studied, when compared to per se treatment.

CONCLUSIONS

The reversal of catalepsy behaviour represents the protective effect of above combination on dopamine neurons in striatum from 6-OHDA toxicity. The mechanism of DFO and DXM combination might be attributed through attenuation of glutamate-induced excitotoxicity in neurons through ameliorating the reactive oxygen species and pro-inflammatory cytokines release. Treatment with DFO and DXM combination could control the multiple events in the pathogenesis of PD.