PTZ-induced Seizure Model Research Articles

Bioactivity Guided Fractionation of Methanol Leaf Extract of Phyllanthus Muellerianus for its Anticonvulsant and Anxiolytic Activities in Mice

Introduction Phyllanthus muellerianus (Kuntze) Exell. (Phyllanthaceae) is an evergreen monoecious shrub widely distributed in tropical and subtropical regions of the world. In South-eastern Nigeria, preparations from the leaf is used in treating pain, epilepsy, convulsion, and other central nervous system disorders. This study was aimed to evaluate the anticonvulsant and anxiolytic properties of leaf extract of Phyllanthus muellerianus (PM) in mice. Materials and methods The methanol leaf extract (ME) of PM was fractionated successively with solvents of increasing polarities to obtain hexane (HF), ethyl acetate (EF) and methanol (MF) fractions. The extract and fractions (100, 200 and 400 mg/kg p.o) were evaluated for anticonvulsant activity using pentylenetetrazol (PTZ)-induced seizure model in mice as activity-guide. EF being the most active fraction was further fractionated with column chromatography and afforded six sub-fractions (F1-F6). The sub-fractions (200 and 400 mg/kg p.o) were evaluated for anticonvulsant activity using PTZ-induced seizure model. ME, EF and F5 which gave the most potent anticonvulsant activity were evaluated for anxiolytic and neurotoxic activities using open field and motor coordination tests respectively at the doses of 200 and 400 mg/kg p.o. Acute toxicity of ME was carried out using Lorke's method. Results were analysed using ANOVA followed by LSD post hoc test. Differences between means were considered significant at p<0.05. Results ME at 200 and 400 mg/kg offered 20% and 40% protection to the mice in PTZ-induced seizures respectively. EF and its F5 sub-fraction completely abolished seizures in mice offering 100% protection and 0% mortality each better than the phenobarbitone standard group (83.3% protection). In the open field test, ME at 400 mg/kg significantly (p<0.05) decreased both the number of line crossing and the number of assisted rearing and was similar to that produced by diazepam. At 200 mg/kg ME significantly (p<0.05) increased the exploratory activities. EF and F5 elicited significant (p<0.05) increase in line crossing. EF significantly (p<0.05) increased both the locomotor and exploratory activities in the mice. ME, EF and F5 significantly (p<0.05) decreased the duration of grooming and number of urination streaks. The total duration of freezes in the ME, EF and F5 were significantly (p<0.05) increased. ME at 400 mg/kg significantly (p<0.05) reduced the time of fall of the mice from the rotarod in the same way as diazepam while EF and F5 (at a lower dose of 200 mg/kg) evoked significant (p<0.05) increase in the time of fall from the rotarod. In acute toxicity study, no mortality was recorded after both phases of the toxicity study. Therefore the LD50 was found to be greater than 5 g/kg. Conclusion The ME possesses anticonvulsant, sedative, and anxiolytic activities while EF and its sub-fraction, F5 possess anticonvulsant and anxiolytic activities devoid of sedative and cognitive impairment. Therefore, F5 may provide a lead for the development of non-sedating anticonvulsant and anxiolytic formulations.

Micronized Resveratrol Shows Anticonvulsant Properties in Pentylenetetrazole-Induced Seizure Model in Adult Zebrafish.

Epilepsy affects 50 million people around the world, and the patients experience cognitive, psychological and social consequences. Despite the considerable quantity of antiepileptic drugs available, 30% of patients still suffer in seizure. Therefore, the advance in therapeutic alternatives is mandatory. Resveratrol has been attracting the attention of many researchers because of its pharmacological potential. However, despite its neuroprotective and anti-epileptic effects, clinical resveratrol use is impaired by its low bioavailability. Here, we applied the supercritical fluid micronization technology (SEDS) to overcome this deficit, and investigated the anticonvulsant potential of micronized resveratrol in a PTZ-induced seizure model in adult zebrafish (Danio rerio). SEDS permits obtaining significantly reduced particle size with a fine size distribution in comparison with the starting material. It can improve the pharmacotherapeutic efficacy. Our data showed that micronized resveratrol decreased the occurrence of the tonic-clonic seizure stage and slowed the development of the seizures in a similar manner of diazepam. Non-processed resveratrol was not able to protect the animals. Furthermore, diazepam decreased the locomotion and exploratory behavior. Differently from diazepam, the micronized resveratrol did not induce behavioral adverse events. In addition, our data showed that the PTZ-induced seizures increased the c-fos transcript levels following the neural excitability. However, the increase in c-fos levels was prevented by micronized resveratrol. In conclusion, our results demonstrate that the micronized resveratrol shows anticonvulsant effect, like the classical antiepileptic drug diazepam in a PTZ-induced seizure model. Excitingly, different from diazepam, micronized resveratrol did not provoke behavioral adverse events.

Effects of Hydro-ethanolic Extract of Tanacetum parthenium and its N-Butanol and Aqueous Fractions on Brain Oxidative Damage in Pentylenetetrazole-Induced Seizures in Mice

Background: Epileptic seizures affect the life of noticeable number of people in all over the world. Tanacetum parthenium (TP) is used in traditional medicine. We studied the effects of hydro- ethanolic extract of TP and its n-butanol and aqueous fractions on brain oxidative damage in pentylenetetrazole (PTZ)-induced seizures in mice. Methods: Male mice were divided into: (1) Control; (2) PTZ (100 mg/kg, i.p.); (3-5) hydro-ethanolic extract of TP (50, 100 and 200 mg/kg); (6) n-butanol (NBut) (100 mg/kg) and (7) aqueous (Aq) (100 mg/kg) fractions. Extracts were injected (i.p.) for 3 days and 30 min before PTZ. Latencies in onset of Minimal Clonic Seizures (MCS) and Generalized Tonic-Clonic Seizures (GTCS) as well as biochemical indicators were evaluated. Results: Medium dose of TP extract and NBut fraction prolonged the MSC and GTCS latencies. Biochemical data confirmed that administration of hydro-ethanolic extract of TP significantly reduced MDA and enhanced total thiol content and the activity of SOD and CAT in brain tissues. Comparison the effect of NBut and Aq fractions with medium dose indicated a higher level of MDA and lower amount of total thiol content and the activity of SOD and CAT in brain tissues of PTZ-Aq100 and PTZ-NBut100 groups than PTZ-TP100 group. Results: demonstrated that the medium dose of TP extract had the most protective effect against brain oxidative damage in PTZ-induced seizure model. N-butanol and aqueous fractions of TP could not exert stronger effect than medium dose on reduction PTZ-induced brain oxidative stress. Results: Medium dose of TP extract and NBut fraction prolonged the MSC and GTCS latencies. Biochemical data confirmed that administration of hydro-ethanolic extract of TP significantly reduced MDA and enhanced total thiol content and the activity of SOD and CAT in brain tissues. Comparison the effect of NBut and Aq fractions with medium dose indicated a higher level of MDA and lower amount of total thiol content and the activity of SOD and CAT in brain tissues of PTZ-Aq100 and PTZ-NBut100 groups than PTZ-TP100 group. Conclusion: Results demonstrated that the medium dose of TP extract had the most protective effect against brain oxidative damage in PTZ-induced seizure model. N-butanol and aqueous fractions of TP could not exert stronger effect than medium dose on reduction PTZ-induced brain oxidative stress.

Evaluation of Anti-Convulsive Properties of Aqueous Kava Extract on Zebrafish Using the PTZ-Induced Seizure Model.

Kava roots have been extensively studied in clinical trials as potential candidate anti-anxiety drugs. However, anti-convulsive properties of various tissues of stems of Kava have not been reported to date. The objective of the study was to evaluate the anti-convulsive potential of aqueous extracts prepared from specific tissues of Kava (Piper methysticum) stems in zebrafish, using the PTZ-induced seizure model. The potency of each extract was compared in terms of the intensity of seizure scores and onset time after pre-treating the zebrafish before the PTZ challenge. The results indicate that aqueous extract of Kava stems without peel after 45 min of pre-treatment exhibited anti-convulsive potential at the dose of 50 mg/L. This study provides evidence to the anti-convulsive properties of peeled Kava stems and its potential for investigation and design of candidate anti-convulsive drugs.

Nanostructured lipid carriers-mediated brain delivery of carbamazepine for improved in vivo anticonvulsant and anxiolytic activity.

The limited brain delivery of carbamezapine (CBZ) presents a major hurdle in the successful epilepsy treatment. The potential of carbamezapine-loaded nanostructured lipid carriers (CBZ-NLCs) for improved brain delivery is investigated in the current study. CBZ-NLCs were prepared by using binary mixture of trilaurin and oleic acid as a lipid core stabilized with Poloxamer 188, Tween 80 and Span 80. CBZ-NLCs were evaluated for physicochemical properties, in vitro release, in vivo brain kinetics, anticonvulsant and anxiolytic activities. The optimized CBZ-NLCs demonstrated nanometric particle size (97.7nm), surface charge of -22mV and high drug incorporation (85%). CBZ-NLCs displayed biphasic release pattern with initial fast followed by sustained drug release. CBZ-NLCs significantly enhanced the AUC of CBZ (520.4µg·h/mL) in brain compared with CBZ dispersion (244.9µg·h/mL). In vivo anticonvulsant activity of CBZ-NLCs in PTZ-induced seizure model showed a significant increase in the onset time (143.0 sec) and reduction in duration (17.2 sec) of tonic-clonic seizures compared with CBZ dispersion (75.4 and 37.2 sec). The anxiolytic activity in light-dark box and elevated-plus maze models also demonstrated superiority of CBZ-NLCs to CBZ dispersion. From the results, CBZ-NLCs presents a promising strategy to improve brain delivery and therapeutic outcomes of CBZ in epilepsy.

Neural Activities in Multiple Rat Brain Regions in Lithium-Pilocarpine-Induced Status Epilepticus Model.

To clarify the different regional brain electroencephalogram (EEG) activities and biochemical responses in seizure and epilepsy models, we assessed the EEG and c-Fos immunolabeling characteristics in a lithium-pilocarpine-induced status epilepticus (SE) model and pentylenetetrazol (PTZ)-induced seizure model. The regional brain activities were evaluated by EEG and c-Fos immunolabeling. ZnT3 immunostaining was performed to observe hippocampal mossy fiber sprouting (MFS) within 7 days after the induction of SE in the lithium-pilocarpine model. The EEG recordings showed distinctive features of activation in different brain areas. With the aggravation of the behavioral manifestations of the seizures, the frequency and amplitude of the discharges on EEG gradually increased. SE was eventually induced and sustained. The labeling of c-Fos was enhanced in the cortex and hippocampal CA1, CA3, and dentate gyrus (DG); however, compared to the PTZ-induced seizure model, c-Fos staining could only be observed in the striatum and thalamus in the lithium-pilocarpine-induced epilepsy model. In each brain region, prominent c-Fos labeling was observed 2 h and 4 h after the induction of SE or seizures and diminished at 24 h. During the lithium-pilocarpine-induced chronic epilepsy phase after SE induction, MFS was observed 7 days after SE and was accompanied by the dynamic evolution of epileptic EEG activities. These findings validated the lithium-pilocarpine-induced SE model as an epilepsy model with a specific spatial-temporal profile of neural activation. The EEG characteristics and c-Fos expression patterns differ from those presented in a previous study using a PTZ-induced seizure model. Hippocampal mossy fiber spouting might be associated with spontaneous seizures during the chronic phase and can be detected at least within 1 week by ZnT3 staining after stimulation.

Sodium Valproate Reduces Neuronal Apoptosis in Acute Pentylenetetrzole-Induced Seizures via Inhibiting ER Stress.

Endoplasmic reticulum (ER) stress has been indicated to be involved in the pathogenesis of epilepsy. Sodium valproate (VPA), one of the most commonly used antiepileptic drugs, is reported to regulate ER stress in many neurological diseases. However, the effect of VPA on ER stress in epilepsy remains unclear. The current study was performed to investigate the role of ER stress in the neuroprotection of VPA against seizure induced by pentylenetetrzole (PTZ). Our results showed that VPA treatment could inhibit the increased expressions of ER stress proteins (GRP78 and CHOP), and significantly reduce neuronal apoptosis in the PTZ-induced experimental seizure model. In addition, Salubrinal, an ER stress inhibitor, was used as a positive control, and exhibited neuroprotective effects via inhibiting excessive ER stress in the seizure model, which further supported that the inhibition in ER stress by VPA treatment could exert neuroprotection in seizures. In summary, our work demonstrated for thefirst timethatER stress was involved in the neuroprotective potential of VPA for seizures.

Anticonvulsant and anti-apoptosis effects of salvianolic acid B on pentylenetetrazole-kindled rats via AKT/CREB/BDNF signaling

Neuronal apoptosis is a regulated intrinsic cell mechanism and common pathological phenomenon after seizures, which involves the protein kinase B/cAMP response element binding protein / brain derived neurotrophic factor (AKT/CREB/ BDNF) signaling pathway. In this study, we aimed to identify the effects of salvianolic acid B (Sal B), a major water-soluble component of the Chinese herb, Danshen, on rats in which seizures had been induced by pentylenetetrazole (PTZ) and the underlying molecular mechanisms mediating these effects. For this, 60 adult male Sprague-Dawley rats were divided into a control group, a ‘PTZ’ group and a ‘PTZ + Sal B’ group. The animals in the control group received an intraperitoneal (i.p.) injection of saline on alternate days for a total of 15 injections and saline orally once a day for 29 days. The animals in the ‘PTZ’ group received PTZ (40 mg/kg, i.p.) on alternate days for a total of 15 injections and saline orally once a day for 29 days. Similarly, the animals in the ‘PTZ + Sal B’ group received PTZ (40 mg/kg, i.p.) on alternate days and Sal B (20 mg/kg) orally once a day for 29 days. Neural density was then evaluated using immunofluorescence (IF) staining of microtubule-associated protein 2 (MAP2). Neuronal apoptosis was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. In addition, the expression of several proteins related to AKT/CREB/BDNF signaling was measured using Western blotting. The results indicated that more severe seizures, decreased neural density, decreased expression of Bcl-2, increased expression of Bax and cleaved caspase-3, and inactivation of AKT/CREB/BDNF signaling occurred in the ‘PTZ’ group in comparison with the control group. However, those changes were suppressed by Sal B. Thus, these data suggest that Sal B has anticonvulsant and anti-apoptotic effects in a PTZ-induced seizure model through activation of the AKT/CREB/BDNF signaling pathways.

Up-regulation of antioxidative proteins TRX1, TXNL1 and TXNRD1 in the cortex of PTZ kindling seizure model mice.

Oxidative stress has been considered as one of pathogenesis of brain damage led by epilepsy. Reducing oxidative stress can ameliorate brain damage during seizures. However, expression levels of important antioxidative enzymes such as thioredoxin-1 (TRX1), thioredoxin-like 1 protein (TXNL1) and thioredoxin reductase 1 (TXNRD1) during seizures have not been investigated. In this study, we examined protein and mRNA expression levels of TRX1, TXNL1 and TXNRD1 in different brain regions in PTZ induced seizure model mice. We found that protein expression levels of TRX1, TXNL1 and TXNRD1 are simultaneously up-regulated by 2- or 3-fold in the cortex of both acute and chronic seizure model mice. But there is no unified expression pattern change of these enzymes in the hippocampus, cerebellum and diencephalon in the seizure model mice. Less extent up-regulation of mRNA expression of these enzymes were also observed in the cortex of seizure mice. These data suggest that antioxidative enzymes may provide a protective effect against oxidative stress in the cortex during seizures.

Study of anticonvulsant activity of acetazolamide on albino rats and its influence on anticonvulsant activity of sodium valproate

Background: Epilepsy is a common neurological disorder. 30-40% of patients will continue to have seizures despite the use of antiepileptic drugs either alone or in combination. The present study is undertaken to evaluate the anticonvulsant activity of Acetazolamide (ACZ) in albino rats and its influence on anticonvulsant activity of sodium valproate.Methods: Albino rats (150-200gms) of male sex were randomly selected, from central animal facility, MMCRI, Mysore. They were divided into 6groups (per model) of 6 rats each, control group-normal saline 0.5ml, standard group-sodium valproate (300mg/kg), dose 1-ACZ (8.75mg/kg), dose 2-ACZ (17.5mg/kg) and dose 3-ACZ (35mg/kg), dose 4-ACZ (8.75mg/kg) with sodium valproate (150mg/kg). The anti-convulsant activity was screened using MES model and PTZ model.Results: Results were analysed by ANOVA followed by post hoc Fisher’s LSD test. The ACZ has shown anticonvulsant activity at the dose of 17.5mg/kg and 35mg/kg body weight and combination of ACZ 8.75mg/kg with sodium valproate 150mg/kg both in MES model and PTZ model. The anticonvulsant activity of ACZ was less when compared to Sodium Valproate in both MES model and PTZ model. The anticonvulsant activity of combination, ACZ 8.75mg/kg with Sodium valproate 150mg/kg was comparable and more significant when compared to standard drug alone in MES model and PTZ model.Conclusions: The ACZ has shown anticonvulsant activity in MES model and PTZ induced seizure model of epilepsy. This study has shown that ACZ potentiated the effect of sodium valproate and can be used as add on drug with sodium valproate in epilepsy.

Micronization potentiates curcumin\u2019s anti-seizure effect and brings an important advance in epilepsy treatment

Epilepsy is one of the most common neurological diseases, and current antiepileptic drugs fail to suppress seizure occurrence in around one third of epileptic patients. Curcumin is a phytochemical with promising effects on epilepsy treatment. However, its application has been hindered by its low bioavailability. In order to improve curcumin’s anti-seizure properties, increasing its bioavailability, here we proposed to micronize the compound through supercritical carbon dioxide processing, a suitable green chemistry technique to prepare and modify material properties. Here we investigated the anti-seizure potential of the classical antiepileptic drug valproate, curcumin in its natural state, and micronized curcumin in a PTZ-induced seizure model in zebrafish (Danio rerio). Concerning seizure development, valproate, curcumin and micronized curcumin showed protective effects, slowing seizure development both in larvae and adult animals. Nevertheless, considering the occurrence of the tonic-clonic seizure stage, only valproate and micronized curcumin reduced it, both in larvae and adult zebrafish, unlike non-processed curcumin. Our obtained results are very promising, since micronized curcumin showed effects that are similar to a classic antiepileptic drug, reducing seizure occurrence and slowing seizure progression.

Evaluation of anticonvulsant activity of Saraca asoca flower (Roxb.) Wilde in Swiss albino mice

Background: Epilepsy is a neurological disorder distressing a large scale of the inhabitants, which accounts for about 1% of the world’s burden of diseases. A large number of groups called antiepileptic drugs are accessible to treat several types of seizures with the objective to decrease seizure incidence and ruthlessness within an outline of an acceptable level of side effects, search for an alternative antiepileptic from natural source, i.e., herbal remedies, which were used traditionally, and safe on human health, is gaining global attention. Aims and Objectives: The objective of the study is intended to evaluate the antiepileptic activity of Saraca asoca flower (Roxb.) Wilde extract of S. asoca flower (ESAF) in Swiss albino mice. Materials and Methods: Ethanolic ESAF was prepared by a continuous method using Soxhlet apparatus with respected temperature. EASF in the doses 50, 100 mg/kg bodyweight along with valproate was administrated to albino mice by oral route followed by antiepileptic activity was evaluated by maximal electroshock (MES) and pentylenetetrazole (PTZ)-induced seizure models. Abolition of tonic hind limb extension (THLE) phase and increase in seizure latency period, when compared to control group, were taken as a measure of protection in MES- and PTZ-induced convulsion model, respectively. The results are expressed as mean ± standard error of the mean. Statistical analysis was done by one-way analysis of variance test followed by post hoc Dunnett’s multiple comparison tests. P < 0.05 was considered statistically significant. Results: ESAF in the dose of 50 and 100 mg/kg bodyweight showed significant antiepileptic property in both MES and PTZ seizure models. There was significant abolition of THLE phase in MES model. There was also significant increase in seizure latency in PTZ-induced seizure model. Conclusion: ESAF possesses significant antiepileptic activity. Further, investigations are required to determine its active constituents and also its mechanism of action.

Anticonvulsant and Antioxidant Effects of Musa sapientum Stem Extract on Acute and Chronic Experimental Models of Epilepsy.

Background:Musa sapientum (banana) plant extract has been shown to possess antioxidant activity in previous studies. Neuronal injury resulting from oxidative stress is an important factor involved in pathogenesis of epilepsy.Objective:The present study aimed to evaluate the anticonvulsant activity of M. sapientum stem extract (MSSE) in acute and chronic experimental models in mice and its effects on various markers of oxidative stress in the brain of pentylenetetrazole (PTZ)-kindled animals.Material and Methods:Maximal electroshock seizures (MES) and PTZ-induced convulsion models were used for acute studies. For the chronic study, the effect of MSSE on the development of kindling was studied. For the evaluation of the effects of MSSE on oxidative stress in brain, malondialdehyde (MDA) and reduced glutathione (GSH) levels were estimated in the brains of the kindled animals.Results:MSSE significantly increased the latency to onset of myoclonic jerks and the duration of clonic convulsions following PTZ administration. The MSSE pretreated group showed significantly reduced mean seizure score on PTZ-induced kindling. There was a significant increase in the brain MDA levels and decrease in GSH levels in response to PTZ-induced kindling. On MSSE pretreatment, there was a significant decrease in the MDA levels in the brains, though the increase in the GSH levels was not significant.Conclusion:The results from this study suggest the presence of significant anticonvulsant activity in MSSE, in both acute and chronic PTZ-induced seizure models, which could be due to its antioxidant activity, as is reflected by the change in oxidative stress markers in brain.SUMMARY Evaluation of the anticonvulsant activity of Musa sapientum and its effects on various markers of oxidative stress in the brain has not been done previously to the best of our knowledgeM. sapientum stem extract (MSSE) significantly increased the latency to onset of myoclonic jerks and the duration of clonic convulsions in the experimental modelsThe MSSE pretreated group showed significantly reduced mean seizure score on pentylenetetrazole (PTZ)-induced kindlingThere was significant increase in the brain malondialdehyde (MDA) levels and decrease in glutathione (GSH) levels in response to PTZ-induced kindlingOn MSSE pretreatment, there was a significant decrease in the MDA levels in the brain, though the increase in the GSH levels was not significant. Abbreviations Used: MSSE: Musa sapientum stem extract, PTZ: Pentylenetetrazole, MES: Maximal electroshock seizures, MDA: Malondialdehyde, GSH: Glutathione, SOD: Superoxide dismutase, THLE: Tonic hindlimb extension

Anticonvulsant profile of the neuroactive steroid, SGE-516, in animal models

Despite the availability of multiple antiepileptic drugs (AED), failure to adequately control seizures is a challenge for approximately one third of epilepsy patients, and new therapies with a differentiated mechanism of action are needed. The neuroactive steroid, SGE-516, is a positive allosteric modulator of both gamma- and delta-containing GABAA receptors. This broad GABAA receptor activity differentiates neuroactive steroids like SGE-516 from benzodiazepines, a class of anticonvulsants which have been shown in vitro to selectively target gamma-subunit containing GABAA receptors. As a neuroactive steroid, SGE-516 has pharmacokinetic properties that are intended to allow for chronic oral dosing. We investigated the anticonvulsant activity of SGE-516 across numerous in vitro and in vivo models of seizure activity. SGE-516 dose-dependently reduced neuronal firing rates and epileptiform activity in vitro. In mice, SGE-516 protected against acute seizures in the PTZ-induced chemo-convulsant seizure model and the 6Hz psychomotor seizure model. In addition, SGE-516 demonstrated anticonvulsant activity in the mouse corneal kindling model. These data suggest that SGE-516 may have potential for development as a novel oral AED for the treatment of refractory seizures.

Evaluation of anticonvulsant activity of polyherbal formulation based on ayurvedic formulation Brihad Panchagavya Ghrita

Background: The aim of the present study was to develop a polyherbal formulation for epilepsy. Present polyherbal formulation (PHF) (containing Operculina turpethum (L.) Silva Manso, Mimosa pudica L., Uraria picta (Jacq.) DC., Cajanus cajan (L.) Millsp, and Lawsonia inermis L.) is based on an ayurvedic formulation Brihad Panchagavya Ghrita indicated for epilepsy. Materials and Methods: To establish the scientific basis of mechanism, we examined the effects of methanolic extract of PHF (100, 200, and 400 mg/kg, p.o.) on maximal electric shock (MES), pentylenetetrazol (PTZ), and isoniazid (INH)-induced convulsions as well as gamma-aminobutyric acid (GABA)-glutamate level in the brain tissues in PTZ-induced seizure model. Phenytoin (25 mg/kg, i.p.) for MES-induced seizure and diazepam (2 mg/kg, i.p.) for PTZ and INH-induced epilepsy were used as reference drugs, respectively. Results: The extract showed no toxicity and significantly prolonged the onset and reduced the duration of the seizures induced by MES. Phenytoin (25 mg/kg, i.p.) completely inhibited the seizures in this model. Similarly, in the seizures induced by PTZ and INH, the extract also prolonged the onset and reduced the duration of the seizures though not in a dose-dependent manner. Diazepam also inhibits the PTZ and INH-induced seizures. The plant extract however showed a significant anticonvulsant activity at 400 mg/kg in comparison with diazepam. The extract also attenuates the chemical (PTZ) induce oxidative stress in the brain. Moreover, the extract (400 mg/kg) also significantly decreases the GABA-transaminase enzyme activity in PTZ model. The PHF was also found to be capable in reversing the INH-induced decline in GABA level and increase in glutamate level in the brain. Conclusions: The results obtained from this work suggest that PHF has anticonvulsant activity, and this supports the use of the formulation traditionally in the treatment of convulsions.

Alteration of pentylenetetrazole-induced seizure threshold by chronic administration of ginger (Zingiber officinale) extract in male mice

Context: Zingiber officinale Roscoe (Zingiberaceae), or ginger, used in traditional Chinese medicine, has antioxidant activity and neuroprotective effects. The effects of this plant on clonic seizure have not yet been studied.Objective: The present study evaluated the anticonvulsant effect of ginger in a model of clonic seizures induced with pentylenetetrazole (PTZ) in male mice.Materials and methods: The anticonvulsant effect of Z. officinale was investigated using i.v. PTZ-induced seizure models in mice. Different doses of the hydroethanolic extract of Z. officinale (25, 50, and 100 mg/kg) were administered intraperitonal (i.p.), daily for 1 week before induction of PTZ. Phenobarbital sodium (30 mg/kg), a reference standard, was also tested for comparison. The effect of ginger on to the appearance of three separate seizure endpoints, e.g., myoclonic, generalized clonic, and tonic extension phase, was recorded.Results: Hydroethanolic extract of Z. officinale significantly increased the onset time of myoclonic seizure at doses of 25–100 mg/kg (55.33 ± 1.91 versus 24.47 ± 1.33 mg/kg, p < 0.001) and significantly prevented generalized clonic (74.64 ± 3.52 versus 47.72 ± 2.31 mg/kg, p < 0.001) and increased the threshold for the forelimb tonic extension (102.6 ± 5.39 versus 71.82 ± 7.82 mg/kg, p < 0.01) seizure induced by PTZ compared with the control group.Discussion and conclusion: Based on the results, the hydroethanolic extract of ginger has anticonvulsant effects, possibly through an interaction with inhibitory and excitatory systems, antioxidant mechanisms, and oxidative stress inhibition.

Evaluation of neuropharmacological effects of aqueous leaf extract of Albizia glaberrima (Leguminosae) in mice

Ethnopharmacological relevanceAlbizia glaberrima is a shrub found in the deciduous forest and jungle of the coastal plain of West Africa. Preparations of the plant are used traditionally in the treatment of fever, pain and central nervous system disorders, including epilepsy. This study was conducted to investigate the neuropharmacological effects of the aqueous leaf extract of Albizia glaberrima in mice. Materials and methodsThe hole-board, elevated plus-maze, thiopentone-induced sleep (anxiolytic/sedative-hypnotic), traction, climbing, inclined screen (muscle relaxant), strychnine-, picrotoxin- and pentylenetetrazole (PTZ)-induced convulsion (anticonvulsant) tests were employed in this study. ResultsAlbizia glaberrima extract at 200mg/kg significantly increased the duration of head dips (p<0.05) and number of open arms entry (p<0.01) compared with control in the hole-board and elevated plus-maze tests, respectively. At 400mg/kg, Albizia glaberrima extract significantly reduced the number of sectional crossings relative to control. The extract at 400mg/kg significantly (p<0.05) increased the duration of sleep compared with control in the thiopentone-induced hypnosis test. Albizia glaberrima extract at 200mg/kg and diazepam (5mg/kg) significantly (p<0.05, 0.01) increased the post-treatment climbing time and reduced the latency to slide down in the climbing and inclined screen tests, respectively. The extract was not effective in the strychnine-induced seizure model, while in the picrotoxin test Albizia glaberrima extract at 100mg/kg significantly (p<0.05) reduced the duration of convulsion while reducing mortality at 400mg/kg, as was the case with diazepam (2mg/kg). The extract and diazepam significantly (p<0.01, 0.001) increased onset and reduced duration of convulsion, with significant level of protection against convulsion and reduction in mortality in the PTZ-induced seizure model. Preliminary phytochemical screening of the extract revealed the presence of phenols>tannins>saponins>flavonoids. The extract was found to be relatively non-toxic when administered p.o. up to 5000mg/kg and the LD50 was 398.11mg/kg when administered i.p. ConclusionsThe aqueous leaf extract of Albizia glaberrima possesses dose-dependent anxiolytic/muscle relaxant (low dose) and sedative-hypnotic/anticonvulsant (high dose) activities possibly mediated via enhancement of GABAergic inhibitory actions.

Seeking potential anticonvulsant agents that target GABAA receptors using experimental and theoretical procedures.

The aim of this study was to identify compounds that possess anticonvulsant activity by using a pentylenetetrazol (PTZ)-induced seizure model. Theoretical studies of a set of ligands, explored the binding affinities of the ligands for the GABA(A) receptor (GABA(A)R), including some benzodiazepines. The ligands satisfy the Lipinski rules and contain a pharmacophore core that has been previously reported to be a GABA(A)R activator. To select the ligands with the best physicochemical properties, all of the compounds were analyzed by quantum mechanics and the energies of the highest occupied molecular orbital and lowest unoccupied molecular orbital were determined. Docking calculations between the ligands and the GABA(A)R were used to identify the complexes with the highest Gibbs binding energies. The identified compound D1 (dibenzo(b,f)(1,4)diazocine-6,11(5H,12H)-dione) was synthesized, experimentally tested, and the GABA(A)R-D1 complex was submitted to 12-ns-long molecular dynamics (MD) simulations to corroborate the binding conformation obtained by docking techniques. MD simulations were also used to analyze the decomposition of the Gibbs binding energy of the residues involved in the stabilization of the complex. To validate our theoretical results, molecular docking and MD simulations were also performed for three reference compounds that are currently in commercial use: clonazepam (CLZ), zolpidem and eszopiclone. The theoretical results show that the GABA(A)R-D1, and GABA(A)R-CLZ complexes bind to the benzodiazepine binding site, share a similar map of binding residues, and have similar Gibbs binding energies and entropic components. Experimental studies using a PTZ-induced seizure model showed that D1 possesses similar activity to CLZ, which corroborates the predicted binding free energy identified by theoretical calculations.

The role for nitric oxide on the effects of hydroalcoholic extract of Achillea wilhelmsii on seizure.

Objective : Nitric oxide (NO) plays an important role both as a consequence and as a cause of epileptic seizures. Regarding the central nervous system depressant effects of Achillea wilhelmsii (A. wilhelmsii), as well the effects of the plant on NO, this study was aimed to elucidate the possible role for nitric oxide on the effects of hydroalcoholic extract of A. wilhelmsii on pentylenetetrazole (PTZ)-induced seizures. Fifty-six male Wistar rats were divided into 7 groups (n=8 in each group) and treated with (1) normal saline, (2) normal saline before pentylenetetrazole (PTZ, 90 mg/kg), (3-7) A. wilhelmsii extract (100, 200, 400, 800, and 1200 mg/kg) before PTZ. Latency to first minimal colonic seizure (MCS) and the first generalized tonic-clonic seizures (GTCS) as well as the mortality rate were recorded. The brain tissues were then removed for biochemical measurements. Fisher's exact probability test as well as analysis of variance (ANOVA), followed by Tukey's test were used for statistical evaluation. Treatment with 100- 1200 mg/kg of the extract did not affect MCS latencies. 400 mg/kg of the extract prolonged GTCS latency (p<0.001), however, the lower and higher doses were not effective. Nitric oxide metabolites concentrations in the hippocampal tissues of the animals treated with 100, 200, and 400 mg/kg of the extract were increased compared with saline (p<0.05-p<0.01). The present study showed that hydroalcoholic extract of A. wilhelmsii affects NO metabolites in brain tissues as well the severity of seizures in PTZ-induced seizure model.

Acute administration of ginger (Zingiber officinale rhizomes) extract on timed intravenous pentylenetetrazol infusion seizure model in mice

Zingiber officinale (Zingiberaceae) or ginger, which is used in traditional medicine has antioxidant activity and neuroprotective effects. The effects of this plant on clonic seizure have not yet been studied. The present study evaluated the anticonvulsant effect of ginger in a model of clonic seizures induced with pentylenetetrazole (PTZ) in male mice. The anticonvulsant effect of Z. officinale was investigated using i.v. PTZ-induced seizure models in mice. Different doses of the hydroethanolic extract of Z. officinale (25, 50, and 100mg/kg) were administered intraperitonal (i.p.), 2 and 24h before induction of PTZ. Phenobarbital sodium (30mg/kg), a reference standard, was also tested for comparison. The effect of ginger on to the appearance of three separate seizure endpoints (myoclonic, generalized clonus and forelimb tonic extension phase) was recorded. The results showed that the ginger extract has anticonvulsant effects in all the experimental treatment groups of seizure tested as it significantly increased the seizure threshold. Hydroethanolic extract of Z. officinale significantly increased the onset time of myoclonic seizure at doses of 25-100mg/kg (p<0.001) and significantly prevented generalized clonic (p<0.001) and increased the threshold for the forelimb tonic extension (p<0.01) seizure 2 and 24h before induction of PTZ compared with control group. Based on the results the hydroethanolic extract of ginger has anticonvulsant effects, possibly through an interaction with inhibitory and excitatory system, antioxidant mechanisms, oxidative stress and calcium channel inhibition.