Dexmedetomidine, an alpha-2 adrenoceptors agonist, provides a neuroprotective effect for dopaminergic neurons in the substantia nigra and attenuates glucose imbalance in the 6-hydroxydopamine animal model of Parkinson's disease.

INTRODUCTION: Studies have shown that dexmedetomidine (DEX, an a2-adrenoceptors agonist) provides a neuroprotective effect and influences blood glucose levels. Here, we evaluated the effect of prolonged treatment with low doses of DEX on the survival rate of dopaminergic (DAergic) neurons in the substantia nigra and also serum glucose levels in 6-hydroxydopamine (6-OHDA) - induced Parkinson's disease (PD) in the rat. MATERIAL AND METHODS: The neurotoxin of 6-OHDA was injected into the medial forebrain bundle by stereotaxic surgery. DEX (25 and 50 µg/kg, i.p) and yohimbine, an a2-adrenoceptor antagonist (1 mg/kg, i.p) were administered before the surgery to the 13 weeks afterward. Apomorphine-induced rotational tests and blood sampling were carried out before the surgery and multiple weeks after that. Thirteen weeks after the surgery, the rats' brain was transcardially perfused to assess the survival rate of DAergic neurons using the tyrosine hydroxylase (TH) immunohistochemistry. RESULTS: DEX remarkably attenuated the severity of rotational behavior and reversed the progress of the PD. It also increased the number of TH-labeled neurons by up to 60%. The serum glucose levels in 6-OHDA-received rats did not change in the third and seventh weeks after the surgery but decreased significantly in the thirteenth week. Treatment with DEX prevented this decrement in glucose levels. On the other hand, Treatment with yohimbine did not affect PD symptoms and glucose levels. CONCLUSION: Our data indicate that DEX through neuroprotective activity attenuates the severity of 6-OHDA-induced PD in rats. DEX might also prevent hypoglycemia during the progress of the PD.

Unraveling the function and structure impact of deleterious missense SNPs in the human OX1R receptor by computational analysis.

The orexin/hypocretin receptor type 1 (OX1R) plays a crucial role in regulating various physiological functions, especially feeding behavior, addiction, and reward. Genetic variations in the OX1R have been associated with several neurological disorders. In this study, we utilized a combination of sequence and structure-based computational tools to identify the most deleterious missense single nucleotide polymorphisms (SNPs) in the OX1R gene. Our findings revealed four highly conserved and structurally destabilizing missense SNPs, namely R144C, I148N, S172W, and A297D, located in the GTP-binding domain. Molecular dynamics simulations analysis demonstrated that all four most detrimental mutant proteins altered the overall structural flexibility and dynamics of OX1R protein, resulting in significant changes in the structural organization and motion of the protein. These findings provide valuable insights into the impact of missense SNPs on OX1R function loss and their potential contribution to the development of neurological disorders, thereby guiding future research in this field.

Trehalose and carnosic acid induced LC3I, LC3II ratio, P62 down-regulation and cleaved caspase 3 expression in neural stem cells.

BACKGROUND: Using neural stem cells (NSCs) in cell therapy and regenerative medicine is a growing knowledge. In this study, the protective role of carnosic acid and trehalose against H2O2-induced oxidative stress in autophagy induction and apoptosis inhibition in NSCs was investigated. MATERIAL AND METHODS: The bone marrow stromal cells (BMSCs) were isolated from the femur of the rat and differentiated into NSCs using basic fibroblast and epidermal growth factors (bFGF and EGF), and B27 serum free media. To evaluate the autophagy, the P62 protein was assessed by immunocytochemistry and LC3II / LC3I ratio by Western blotting. Further, we used 3-Methyladenine (3-MA), a widely used autophagy inhibitor to study whether combined treatment of 3-MA with carnosic acid and trehalose modulates autophagy in NSCs. For studying apoptosis, the cleaved caspase-3 protein was evaluated. Carnosic acid and trehalose increased the survival of the NSCs. RESULTS: The H2O2 decreased the autophagy and induced apoptosis with increasing time during 24 hours, however, a pre-treatment with 2 µM carnosic acid and trehalose 3 % induced the autophagy proteins (while increasing the LC3II / LC3I ratio and decreasing the P62) and decreased the apoptosis (while decreasing the expression of the cleaved caspase-3). The results showed that the carnosic acid and trehalose increased the survival of NSCs against the oxidative stress caused by H2O2, decreased apoptosis, and induced autophagy. CONCLUSION: Due to the carnosic acid and trehalose unique properties and its low toxicity, it can be used as an agent in cellular transplantation for reducing oxidative stress and inducing autophagy (Fig. 4, Ref. 37).

Dopaminergic neuronal death in the substantia nigra associates with change in serum levels of TNF-α and IL-1ß; evidence from early experimental model of Parkinson's disease.

PURPOSE: Studies have shown that inflammation plays a key role in etiology of Parkinson's disease (PD). However, human studies which have evaluated association between PD and serum levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1ß) have reported conflicting results. In this study, serum and striatum levels of these cytokines were evaluated in 6-hydroxydopamine (6-OHDA) animal model of PD. METHOD: The neurotoxin of 6-OHDA was injected into medial forebrain bundle of right hemisphere and behavioral tests were carried out to eight weeks thereafter to evaluate severity of PD and its progress. Blood was collected before the toxin and in second and eight weeks after that. Survival of dopaminergic (DAergic) neurons in substantia nigra was assessed by immunohistochemistry. TNF-α and IL-1ß levels were determined using ELISA kits. RESULT: Severity of behavioral symptoms was gradually increased in 6-OHDA-treated rats. They showed a decrease in serum TNF-α level in the eight week and increase in IL-1ß both in the second and eight weeks. They were divided into two subgroups, symptomatic and asymptomatic with severe and moderate degrees in DAergic neuronal death. Significant decrease in serum TNF-α was only observed in the symptomatic subgroup but IL-1ß increased in both subgroups. Also, striatal levels of both cytokines were higher in the lesioned hemisphere. CONCLUSION: Increase in serum IL-1ß level can reflect moderate degree of lesion in substantia nigra and thereby is used for prognosis of PD before its clinical symptoms are appeared. On the other hand, an increase in serum TNF-α is appeared in advanced stage of PD.

Blockage of ventrolateral periaqueductal gray matter cannabinoid 1 receptor increases dental pulp pain and pain-related subsequent learning and memory deficits in rats.

Cannabinoid 1 receptor (CB1R) signaling has a pivotal role in the modulation of both pain and cognitive responses. This study aims at investigating the role of CB1R in the ventrolateral periaqueductal gray matter (vlPAG) on both pulpal pain and pain-related subsequent changes in learning and memory performances in rats. The adult male Wistar rats were cannulated in the vlPAG. The rats were pretreated by intra-vlPAG administration of selective CB1R antagonist AM-251 (2, 4 and 8 µg/rat) and vehicle dimethylsulfoxide. The drugs were microinjected 20 min before the induction of capsaicin-induced pulpalgia. The nociceptive behaviors were recorded for 40 min. Then, passive avoidance and spatial learning and memory were assessed using the shuttle box and Morris water maze tests, respectively. Following the administration of intradental capsaicin, there was a significant nociceptive response that increased after an induced blockage of CB1R by AM-251 at 4 and 8 µg. In addition, capsaicin impaired passive avoidance and spatial memory performance of rats. Microinjection of AM-251, prior to capsaicin, could dose-dependently exaggerate capsaicin-related learning and memory deficits in both tests. The present data indicated that the vlPAG endocannabinoid system is involved in the modulation of pain signals from dental pulp. It was also accompanied by learning and memory impairments.

Dopaminergic Neuronal Death in Substantia Nigra Associates with Serum Levels of Total Bilirubin, Selenium, and Zinc: Evidences from 6-Hydroxydopamine Animal Model of Parkinson's Disease.

Mild to moderate dopaminergic (DA) neuronal death in substantia nigra pars compacta (SNc) as the main pathological hallmark of Parkinson's disease (PD) is usually silent and does not produce marked clinical symptoms. In this study, we investigated the association between SNc DA neuronal loss and serum levels of total bilirubin (TB), selenium (Se), and zinc (Zn) in 6-hydroxydopamine (6-OHDA) animal model of PD. The neurotoxin of 6-OHDA was injected into the medial forebrain bundle of right hemisphere by stereotaxic surgery. Two conventional behavioral tests were carried out in several steps after the toxin to confirm the model reproduction and quantify severity and progress of 6-OHDA-induced PD. Blood samples were collected within 1 week before the toxin and in the second, fifth, and eighth weeks thereafter. Immunohistochemistry (IHC) assessments were performed on the rat's brain to determine the severity of DA neuronal loss in SNc. The severity of behavioral symptoms and TB levels were progressively increased in 6-OHDA-treated rats. On the other hand, Se and Zn levels in them were lower than control. These changes were observed in rats with severe or mild behavioral symptoms. Also, IHC revealed that changes in TB, Se, and Zn associate with SNc DA neuronal loss but do not correlate with its severity. Significant changes in serum levels of TB, Se, and Zn in the mild SNc DA neuronal loss suggest them as valuable parameters for establishment of a serum profile for early detection of PD.

Chronic and progressive dopaminergic neuronal death in substantia nigra associates with a decrease in serum levels of glucose and free fatty acids, the role of interlokin-1 beta.

Human studies indicate that Parkinson's disease (PD) associates with disruption in metabolism of glucose and free fatty acids (FFA). Studies have shown that interlukin-1beta (IL-1ß) causes hypoglycemia through insulin- independent mechanisms. Here, we investigated association between dopaminergic neuronal death, as the main pathophysiological mechanism underlying PD, and serum levels of glucose, FFA and IL-1ß in 6-hydroxydopamine (6-OHDA) animal model of PD. Neurotoxin of 6-OHDA was injected into medial forebrain bundle and multiple behavioral testes were carried out during eight weeks thereafter. Blood was collected before the toxin and in second and eight weeks thereafter. Then, brain of the animals was perfused to assess survival of dopaminergic (DAergic) neurons in substantia nigra by tyrosine hydroxylase (TH) immunohistochemistry. Glucose, FFA and IL-1ß levels were determined using calorimetric method and specific ELISA kits. In compare to control, 6-OHDA- treated rats had less glucose and FFA levels in the eight week and higher IL-1ß level in the both second and eight weeks. Based on severity of behavioral symptoms, 6-OHDA- treated rats were divided into two subgroups of severe and mild. Number of TH- positive cells in these subgroups was 83 and 45% less than that in control. Also, both subgroups showed less weight gain, lower glucose and FFA and higher IL-1ß in eight week. Our data indicate that moderate to severe progressive DAergic neuronal death in substantia nigra associates with a decrease in serum levels of glucose and FFA. Increase in IL-1ß production following neuronal death possibly mediated this decrease.

A study on the correlation between smoking and non-enzymatic antioxidant factors of the saliva of healthy smokers and non-smokers / Estudo da correlação entre fumo e fatores antioxidantes não-enzimáticos na saliva de pacientes saudáveis fumantes e não fumantes

Objective: Smoking is among the most destructive habits which have numerous effects on the body.The chemical components of cigarettes destroy the anti-oxidant content of the saliva.In this study, the concentration of albumin and uric acid of healthy non-smokers and smokers was measured based on the frequency of smoking. Material and Methods:In this cross-sectional study, 26 heavy smokers, 27 normal smokers, and 29 non-smokers between the ages of 25 to 40 were selected.The subjects did not suffer from any systemic or periodontal conditions.Unstimulated saliva was collected by spitting. The level of salivary albumin was measured by Bromocresol Green, and the level of salivary uric acid was measured by the uricase method.The selected method of analysis, using SPSS software, was One-Way ANOVA. Results: Mean albumin content of saliva was 33.52 ± 1.52 mg/dl in non-smokers and 23.88 ± 8.93 mg/dl in heavy smokers.The mean uric acid concentration in non-smokers was 2.98 ± 0.79 µmol/L and in heavy smokers was 2.32 ± 0.77 mg/dL.The differences between levels of both salivary uric acid and salivary albumin were significant in heavy smokers and non-smokers(P=0.001). Conclusion: Based on the findings of this study, saliva concentrations of both Albumin and Uric Acid change based on the frequency of smoking.Decreased level of salivary albumin and decreased level of salivary uric acid can be considered as markers of the harmful effects of smoking on oral health. (AU)

Objetivo: Tabagismo está entre os hábitos mais deletérios, que causam inúmeros efeitos no organismo. Os componentes químicos do cigarro destroem os compostos anti-oxidantes da saliva. Neste estudo, a concentração de albumina e ácido úrico em pacientes saudáveis fumantes e não-fumantes foi mensurada e correlacionada coma frequência de fumo. Material e Métodos: Neste estudo transversal, 26 fumantes pesados, 27 fumantes moderados, e 29 não fumantes entre 25 e 40 anos foram incluídos. Os participantes não apresentavam nenhuma condição sistêmica ou periodontal. Saliva não estimulada foi coletada. Os níveis salivares de albumina foram avaliados por Verde de bromocresol, e o nível de ácido úrico foi mensurado pelo método de uricase. Os dados foram analisados utilizando-se One-way ANOVA no software SPSS. Resultados: A albumina salivar foi de 33.52 ±1.52 mg/dl nos não-fumantes e 23.88 ± 8.93 mg/dl nos fumantes pesados. A concentração média de ácido úrico em não-fumantes foi de 2.98 ± 0.79 µmol/L e em pacientes fumantes pesados de 2.32 ± 0.77 mg/dL. As diferenças entre os níveis de ambos, ácido úrico e albumina, foi significante entre fumantes pesados e não-fumantes (p=0.001). Conclusão: Baseados nos achados deste estudo, concentrações salivares de albumina e ácido úrico baseados na frequência de fumo. A diminuição dos níveis salivares de albumina e ácido úrico podem ser considerados marcadores dos efeitos nocivos do cigarro na saúde oral(AU)

Hydrogen sulfide attenuates induction and prevents progress of the 6-hydroxydopamine-induced Parkinsonism in rat through activation of ATP-sensitive potassium channels and suppression of ER stress.

PURPOSE: Studies argue in favor of hydrogen sulfide (H2S) as the next potent therapeutic agent for neurodegenerative diseases. In present study, we investigated the effect of long term treatment with NaHS (as donor of H2S) on induction and progress of the 6-hydroxydopamine (6-OHDA) -induced Parkinsonism in rat. METHODS: The 6-OHDA was injected into medial forebrain bundle of right hemisphere by stereotaxic surgery. Behavioral tests and treatments were carried out to eight weeks after the toxin. Immunohistochemistry and western blotting were carried out to evaluate the survival of tyrosine hydroxylase (TH) -positive neurons in substantia nigra (SN) and also expression of glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP), the markers of endoplasmic reticulum (ER) stress, in striatum and SN. RESULTS: Eight weeks assessment of the behavioral symptoms showed that NaHS especially at dose of 100 µmol/kg attenuates remarkably induction of the Parkinsonism and prevents its progress. NaHS also increased the survival of TH- positive neurons and suppressed 6-OHDA- induced overexpression of GRP78 and CHOP. Blockade of ATP-sensitive potassium (K-ATP) channels with glibenclamide (Glib) prevented markedly the effect of NaHS on both the induction phase and survival of TH- positive neurons. But Glib did not affect the preventing effect of NaHS on the progress phase and its suppressing effect on the overexpression of ER stress markers. CONCLUSION: H2S attenuates induction of the 6-OHDA- induced Parkinsonism and also increases the survival of dopaminergic neurons through activation of K-ATP channels. H2S also prevents progress of the Parkinsonism probably through suppression of ER stress.

Evaluation of the Association Between Serum Levels of Testosterone and Prolactin With 6- Hydroxydopamine-Induced Parkinsonism in Male Rats.

INTRODUCTION: Parkinson's Disease (PD) associates with changes in sex hormones; however, it remains unknown whether this is either a cause for or a result of the disease. To further evaluate it, we investigated if the development of 6-Hydroxydopamine (6-OHDA)-induced Parkinsonism changes the serum levels of testosterone and prolactin or not. METHODS: 6-OHDA was injected into the medial forebrain bundle using stereotaxic surgery. The development of Parkinsonism was evaluated by apomorphine-induced rotational test and the immunofluorescence labeling of Dopaminergic (DA) neurons in substantia nigra. The necessary blood samples were collected before the toxin and in the third and sixth weeks afterward. The hormones levels were determined using Enzyme-Linked Immunosorbent Assay (ELISA) kits. RESULTS: The severity of rotations was different among 6-OHDA-treated rats; accordingly, they were divided into two subgroups of severe and mild parkinsonian rats. The degeneration of DA neurons was observed in both subgroups; however, it was significantly less in the mild group. In the sixth week after the toxin, testosterone level increased but only in the severe subgroup. Prolactin increased in both subgroups in the third week after the toxin but returned to normal in the sixth week. There was no association between the pre-toxin levels of these hormones and the intensity of Parkinsonism. CONCLUSION: Our findings indicated that the development of 6-OHDA-induced Parkinsonism increases the serum levels of testosterone and prolactin. Increased prolactin occurred earlier and was observed in rats with less DA neuronal loss. Therefore, prolactin levels can predict the death of DA neurons before the clinical signs of PD were revealed.

Dexmedetomidine attenuates the induction and reverses the progress of 6-hydroxydopamine- induced parkinsonism; involvement of KATP channels, alpha 2 adrenoceptors and anti-inflammatory mechanisms.

BACKGROUND: Studies have shown that dexmedetomidine (DEX), a potent α2-adrenoceptors agonist provides neuroprotection through suppression of inflammatory response. In present study, we examined effect of DEX and its underlying mechanisms on the induction and progress of 6-OHDA- induced Parkinsonism in rat. MATERIAL AND METHODS: The 6-OHDA was injected into the medial forebrain bundle of right hemisphere by stereotaxic surgery and then, behavioral tests carried out within second, fourth, sixth and eighth weeks post-surgery. All treatments were started before the toxin and continued to eight weeks afterwards. Striatal levels of dopamine, TNF-α and IL-6 were measured within the eighth week after the toxin by enzyme-linked immunosorbent assay kits. RESULTS: DEX at dose of 50 µg/kg attenuated significantly the intensity of 6-OHDA- induced behavioral symptoms in the second week post-surgery. DEX also attenuated remarkably 6-OHDA- induced reduction in striatal dopamine level. These effects were also observed in rats treated by both DEX and yohimbine (YOH), a selective α2-adrenoceptors antagonist but were not observed in rats treated by both of DEX and glibenclamide (Glib), an ATP-sensitive potassium (KATP) channels blocker. DEX also reversed the progressive increase in intensity of the behavioral symptoms and reversed 6-OHDA- induced overproduction of TNF-α and IL-6. These effects were reversed by YOH but not Glib. CONCLUSION: Our findings indicate that DEX attenuates the induction and reverses the progress of 6-OHDA- induced Parkinsonism through activation of KATP channels and α2-adrenoceptors, respectively. Through activation of α2-adrenoceptors, DEX also exerts anti-inflammatory effect which is possibly another mechanism underlying the DEX's antiparkinsonism effect.

Evaluation of the antiparkinsonism and neuroprotective effects of hydrogen sulfide in acute 6-hydroxydopamine-induced animal model of Parkinson's disease: behavioral, histological and biochemical studies.

INTRODUCTION: Studies have shown that hydrogen sulfide (H2S), a gaseous neurotransmitter, has neuroprotective effect. Here, we evaluated the neuroprotective activity of H2S in acute 6-hydroxydopamine (6-OHDA) animal model of Parkinson's disease (PD). METHODS: 6-OHDA was injected through stereotaxic surgery into medial forebrain bundle (MFB) of the right hemisphere to induce severe and fast degeneration in dopaminergic neurons of substantia nigra (SN). NaHS, as donor of H2S, was daily injected at doses of 3 and 5.6 mg/kg for seven days starting a few hours before the surgery. A series of behavioral tests were carried out and then, remaining tyrosine hydroxylase (TH)-positive neurons in substantia nigra pars compacta (SNc) was determined using immunohistfluresance staining. Striatal dopamine level and oxidative stress markers were also measured in the brain homogenates using immunosorbent assay kits. RESULTS: NaHS attenuated apomorphine-induced rotational activity, decreased bias swings in elevated body swing test and increased falling time in rotarod test. Our histological and biochemical data demonstrated that NaHS treatment increases the survival of TH-positive neurons in SNc and also reduces the decreasing effect of 6-OHDA on striatal dopamine level. NaHS also reduced 6-OHDA-induced malondialdehyde overproduction but had no effect on the superoxide dismutase and glutathione peroxidase activity. CONCLUSION: Our results show that H2S produces significant antiparkinsonism and neuroprotective effects against 6-OHDA neurotoxicity. Since injection of 6-OHDA into MFB produces severe lesion in SN dopaminergic neurons similar to this lesion in the onset of PD in human being, our data recommend H2S as potential therapeutic target for treatment of this disease.

Changes in the Serum Urate Level Can Predict the Development of Parkinsonism in the 6-Hydroxydopamine Animal Model.

Epidemiological studies indicate that a higher plasma level of uric acid (UA) associates with the reduced risk of Parkinson's disease (PD). To confirm the role of UA as a biomarker for PD, we evaluated changes in the serum UA level in the 6-hydroxydopamine (6-OHDA)-induced hemiparkinsonism in rat. For this purpose, 6-OHDA was administered in the medial forebrain bundle by stereotaxic surgery. According to the apomorphine-induced rotational test, the increased intensity of behavioral symptoms as a function of time was associated with the further reduction of UA level. On the other hand, the level of UA increased in the midbrain of the injured hemisphere. The level of reduction in the serum UA level of rats with severe and moderate symptoms was significantly higher than that of rats with mild symptoms. The immunohistofluorescence and biochemical analyses showed that the serum UA level was also correlated with the death of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra pars compacta (SNc), reduced level of striatal dopamine, and severity of oxidative stress in the midbrain. The rats with mild symptoms also showed a significant decrease in TH-positive neurons and striatal dopamine level. These findings suggest a positive correlation between the level of reduction in the serum urate level and severity of 6-OHDA-induced Parkinsonism. In addition, our findings indicated that UA had no marked neuroprotective effects, at least at concentrations obtained in this study. On the other hand, UA was introduced as a biomarker for PD, as a significant decline was observed in the serum UA level of rats with mild behavioral symptoms but with significant dopaminergic cell death in the SNc.

Involvement of adenosine triphosphate-sensitive potassium channels in the neuroprotective activity of hydrogen sulfide in the 6-hydroxydopamine-induced animal model of Parkinson's disease.

Studies have shown that hydrogen sulfide (H2S) exerts a neuroprotective effect and may have a therapeutic value for treating neurodegenerative diseases including Parkinson's disease. However, little is known about the mechanisms underlying the neuroprotective activity of H2S in vivo. Here, we evaluated the effect of glibenclamide, an ATP-sensitive potassium channel blocker, on the neuroprotective activity of H2S in the 6-hydroxydopamine (6-OHDA) animal model of Parkinson's disease. 6-OHDA was administered by stereotaxic surgery into the medial forebrain bundle. Sodium hydrosulfate (NaHS, 3 and 5.6 mg/kg), as a donor of H2S, alone or in combination with glibenclamide (5 mg/kg), was daily injected for 7 days starting 1-2 h before the stereotaxic surgery. After an apomorphine-induced rotational test, the number of tyrosine hydroxylase-positive neurons in the substantia nigra pars compacta was determined by immunofluorescence. The striatal dopamine level and oxidative stress markers were also measured in brain homogenates. Pretreatment with NaHS significantly attenuated 6-OHDA-induced motor asymmetry in the rotational test. Histological and biochemical evaluations demonstrated that NaHS, especially at high dose, increased the survival of tyrosine hydroxylase-positive neurons in the substantia nigra pars compacta and reduced the decreasing effect of 6-OHDA on striatal dopamine levels. However, co-administration of glibenclamide reversed the antiparkinsonian and neuroprotective effects of NaHS. However, glibenclamide did not change the reducing effect of NaHS on 6-OHDA-induced overproduction of malondialdehyde. Our data show that ATP-sensitive potassium channels are involved in the antiparkinsonian and neuroprotective effects of H2S in the 6-OHDA animal model of Parkinson's disease.

The Anti-Parkinsonism Effects of KATP Channel Blockade in the 6-Hydroxydopamine-Induced Animal Model: The Role of Oxidative Stress.

INTRODUCTION: Studies suggest that ATP-sensitive potassium (KATP) channels are a potential pharmacotherapeutic target for neuroprotection in neurodegenerative diseases. The current study aimed at evaluating the effect of pretreatment with glibenclamide (Glib) and B vitamins supplement on the severity of behavioral symptoms in 6-hydroxydopamine (OHDA)-induced Parkinsonism. Also malondialdehyde (MDA) concentration was measured in the blood and brain suspensions to find probable neuroprotective mechanism of Glib. METHODS: The 6-OHDA was injected into striatum of rats by stereotaxic surgery. Treatment with Glib and B vitamins was started before the surgery and continued up to 3 weeks after that. Development and severity of Parkinsonism were evaluated by conventional behavioral tests. MDA values were measured spectrophotometrically using thiobarbituric acid and MDA standard curve. RESULTS: Pretreatments with Glib, at both doses of 1 and 5 mg/kg or B vitamins significantly ameliorated severity of the behavioral symptoms. Pretreatment with a combination of Glib and B vitamins was more effective than pretreatment with Glib or B vitamins alone. Also, pretreatment with B vitamins, Glib, or a combination of them reduced MDA concentration in the brain suspensions. Decrease in MDA concentration in the group of rats that received a combination of B vitamins and Glib was more prominent than that of the Glib groups. CONCLUSION: As severity of the behavioral symptoms in the 6-OHDA-induced Parkinsonism reflects the degree of the lesion in Substantia Nigra (SN) dopaminergic neurons, it is suggested that Glib pretreatment has neuroprotective effect against 6-OHDA-induced neurotoxicity. The current study data also showed that this effect may be mediated by antioxidant effect of Glib.

Blockade of fast A-type and TEA-sensitive potassium channels provide an antiparkinsonian effect in a 6-OHDA animal model.

OBJECTIVE: To evaluate the effect of K+ channels inhibitors in treatment of parkinson`s disease (PD). METHODS: This prospective comparative study was conducted in the Qazvin University of Medical Sciences, Iran, from April 2015 to January 2016. Male rats (n=37) received intraperitoneal doses of TEA (2 and 5 mg/kg) or 4-AP (0.5 and 1 mg/kg) twice-daily, before a stereotactic injection of 6-hydroxydopamine (6-OHDA) for the following 7 days. The 6-OHDA was injected into right medial forebrain bundle (MFB) of the rat brains. Development and severity of PD were assessed using the apomorphine-induced rotational test, the elevated body swing test and rotarod tests. Concentration of malondialdehyde (MDA), a marker of oxidative stress, was measured in rat sera. RESULTS: Tetraethylammonium and 4-AP significantly reduced the number of apomorphine-induced rotations and improved motor learning in the rotarod test at both doses. Administration of 4-AP and TEA together was more effective than single administration of either agent. Malondialdehyde measurement showed that pretreatment with TEA could not prevent 6-OHDA-induced oxidative stress. CONCLUSION: Our results showed that pretreatment with TEA and 4-AP has a neuroprotective effect against 6-OHDA in dopaminergic neurons in the substantia nigra.

Pretreatment with potassium channel blockers of 4-aminopyridine and tetraethylammonium attenuates behavioural symptoms of Parkinsonism induced by intrastriatal injection of 6-hydroxydopamine; the role of lipid peroxidation.

OBJECTIVES: Potassium channels participate in cellular and molecular signalling pathways regulating the life and death of neurons. In this study, effect of pretreatment with potassium channel blockers of 4-aminopyridine (4-AP) and tetraethylammonium (TEA) on the behavioural symptoms of 6-hydroxydopamine (6-OHDA)-induced Parkinsonism was evaluated. METHODS: 6-OHDA was injected into right striatum of adult male Wistar rats using stereotaxic surgery. Severity of 6-OHDA-induced Parkinsonism was assessed by conventional behavioural tests. 4-AP and TEA were injected twice per day intraperitoneally, before 6-OHDA injection to 15 days after that. Also, malondialdehyde (MDA) concentration as a marker of oxidative stress was measured in rat sera. RESULTS: Pretreatment with 4-AP (0.5 and 1 mg/kg) and TEA (2 and 5 mg/kg) attenuated significantly behavioural symptoms of 6-OHDA-induced Parkinsonism. Application of both 4-AP and TEA together was more effective than the effect of each one of these blockers alone. 6-OHDA increased MDA concentration but pretreatment with 4-AP prevented of 6-OHDA-induced increase in MDA. On the other hand, pretreatment with TEA and combination of TEA and 4-AP could not prevent of 6-OHDA-induced oxidative stress. DISCUSSION: Since severity of behavioural symptoms of 6-OHDA-induced Parkinsonism is correlated to the degree of nigral dopaminergic cell death, we suggest that antiparkinsonism effect of TEA and 4-AP was mediated by their neuroprotective effect. Because, both Parkinsonism in rat and PD in human, the main pathophysiological hallmark, is neurodegeneration of dopaminergic neurons in substantia nigra, we suggest doing clinical trials for evaluation of effectiveness of 4-AP and TEA in slowing down of PD progress.

Apoptosis Cell Death Effect of Scrophularia Variegata on Breast Cancer Cells via Mitochondrial Intrinsic Pathway.

PURPOSE: Scrophularia variegata M. Beib. (Scrophulariaceae) is an Iranian medicinal plant which is used for various inflammatory disorders in traditional medicine. In this study we evaluated the anti-cancer and cytotoxic effects of the Scrophularia variegata (S. variegata) ethanolic extract on the human breast cancer cell line. METHODS: The cytotoxicity effect of the extract on MCF-7 cells was evaluated by MTT assay. In addition, Caspase activity, DNA ladder and Cell death were evaluated by ELISA, gel electrophoresis and Annexin V-FITC/PI staining, respectively. RESULTS: The S. variegata extract showed significant effect cytotoxicity on MCF-7 human breast cancer cell line. Treatment with the extract induced apoptosis on the breast cancer cells by cell cycle arrest in G2/M phase. The results indicated that cytotoxicity activity was associated with an increase of apoptosis as demonstrated by DNA fragmentation as well as an increase of the amount of caspase 3 and caspase 9. In addition, the phytochemical assay showed that the extract had antioxidant capacity and also flavonoids, phenolic compounds and phenyl propanoids were presented in the extract. CONCLUSION: Our findings indicated that S. variegata extract induced apoptosis via mitochondrial intrinsic pathway on breast cancer by cell cycle arrest in G2/M phase and an increase of caspase 3 and caspase 9. However future studies are needed.