Anticonvulsant effects of Cymbopogon giganteus extracts with possible effects on fully kindled seizures and anxiety in experimental rodent model of mesio-temporal epilepsy induced by pilocarpine.

ETHNOPHARMACOLOGICAL RELEVANCE: Epilepsy is a neurological disorder of the brain characterized by periodic and unpredictable occurrence of a transient behavior alteration due to the rhythmic, synchronous and disordered firing of brain neuron. Worldwide, approximately 50 million people currently live with epilepsy and close to 80% of people with epilepsy live in poor countries. However, it was noticed in many countries worldwide that people with epilepsy and their families suffer from stigma and discrimination and that situation exposes them to high psychological conditions such as depression and anxiety as well as more physical problems including bruising and fractures from injuries related to seizures. However, several plants-based products used for epilepsy and anxiety treatments in different system of folk medicine have exhibited a significant anti-epileptic and antianxiety activities using animal models with fewer side effects. AIM OF THE STUDY: The study aimed at evaluating the antiepileptic, status post-epilepticus and anxiolytic effects of Cymbopogon giganteus decoction in rat model induced by pilocarpine. MATERIALS AND METHODS: A total of 90 rats were partitioned into 7 groups and treated as follow: animals of groups I (normal control) and II (considered the negative control) received distilled water (10 mL/kg); while groups III, IV, V, and VI were treated with the C. giganteus extract at 34, 85, 170 and 340 mg/kg p.o, respectively; and the group VII (considered positive control) received sodium valproate at 300 mg/kg, i.p. After 40 min post-treatment, a single dose of n-methyl-scopolamine (1 mg/kg, i.p) was administered to animals of groups (II, III, IV, V, VI, VII) followed by pilocarpine (360 mg/kg, i.p). Animal of group I (normal group) received distilled water. Rats were further observed for 6 h to evaluate the severity and the duration of the acute seizures of epilepsy according to Racine scale. Anxious behavior status post-epilepticus was also assessed in the same rats used above in the Elevated Plus Maze and number of entries into the open or closed arms and the time spent on either open or closed arms of the platform were recorded. Animals were also evaluated on Open Field Test and the number of rearing, crossing, grooming, defecation and center time were registered. RESULTS: C. giganteus decoction significantly (P < 0.05) reduced the animal mortality, the number and duration of convulsions and effectively increased the latency of convulsions. The plant extract significantly (P < 0.05) improved GSH level and SOD activity, reduced MDA and CAT activity, increased GABA level and decreased GABA-t activity in hippocampus. The anxiety induced by pilocarpine was also significantly (P < 0.05) inhibited by the extract of the plant. CONCLUSIONS: Thus, C. giganteus has demonstrated its antiepileptic and anxiolytic activities in rat model and may be used as preventive measure for patients suffering from epilepsy seizures and anxiety.

Neuroprotective role of apocynin against pentylenetetrazole kindling epilepsy and associated comorbidities in mice by suppression of ROS/RNS.

Epilepsy is a neurological disease that transpires due to the unusual synchronized neuronal discharge within the central nervous system, which drives repetitious unprovoked seizures. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is a complex enzyme accountable for reactive oxygen species (ROS) production, neurodegeneration, neurotoxicity, memory impairment, vitiates normal cellular processes, long term potentiation, and thus, implicated in the pathogenesis of epilepsy. Therefore, the present study was sketched to examine the neuroprotective effect of apocynin, NADPH oxidase inhibitor in pentylenetetrazole kindling epilepsy, and induced comorbidities in mice. Mice (either sex) were given pentylenetetrazole (35 mg/kg, i.p.) every other day up to 29 days, and a challenge test was executed on the 33rd day. Pretreatment with apocynin (25, 50, and 100 mg/kg, i.p.) was carried out from 1st to 33rd day. Rotarod and open field test were performed on the 1st, 10th, 20th, and 30th days of the study. Animals were tutored on the morris water maze from 30th to 33rd day, and the retention was registered on the 34th day. Tail suspension test and elevated plus maze were sequentially performed on the 32nd and 33rd day of the study. On the 34th day, animals were sacrificed, and their brains were isolated to conduct biochemical estimation. NADPH oxidase activation due to chronic pentylenetetrazole treatment resulted in generalized tonic-clonic seizures, enhanced oxidative stress, remodeled neurotransmitters' level, and resulted in comorbidities (anxiety, depression, and memory impairment). Pretreatment with apocynin significantly restricted the pentylenetetrazole induced seizure severity, ROS production, neurotransmitter alteration, and comorbid conditions by inhibiting the NADPH oxidase enzyme.

Morphological changes in the substantia nigra pars reticulata of the mice during kindling.

Substantia nigra pars reticulata (SNpr) has been implicated in modulation, propagation and cessation of seizures. This study aimed to determine whether structural changes occur in SNpr during kindling. Male mice were randomly divided into four groups including early and late-phase kindled groups and their time-matched controls. Kindling was induced by every other day administration of a subconvulsive dose of PTZ (40 mg/kg, i.p.). The first occurrence of seizure behaviors was used to categorize the early and late phases of kindling. There was no significant difference in the volume of SNpr between the early- and late-phase kindled groups. The diameter of SNpr was significantly increased in the early phase group and decreased in the late phase group as compared to their matched controls (p < 0.05). Reduced neural cells and increased dead cell numbers were observed in the SNpr of the late-phase group in comparison to its control group (p < 0.05). These findings suggest that SNpr is a sensitive and vulnerable structure involving seizure propagation in the processes of epileptogenesis.

Response to sertraline and antiepileptic drugs in pentylenetetrazole kindling in rats.

Anti-epileptic drugs (AEDs) are the mainstay of epilepsy treatment but these may be a potential risk factor for behavioral disturbances particularly depression which requires treatment. In this study, the effect of antidepressant sertraline (SRT) in combination with AEDs sodium valproate (SV) and levetiracetam (LEV) on seizures, cognitive impairment and oxidative stress in rats was evaluated. After administration of 24th injection of pentylenetetrazole (PTZ), 77.8% rats were kindled. Administration of SRT showed no protective effect on kindling development while SV was 100% protective. With LEV 42.9% were kindled. On combining SRT with SV or LEV 25% and 20% rats were kindled. A significant increase in latency to reach platform zone in Morris water maze(MWM), and increased transfer latencies in Elevated plus maze(EPM) was observed in PTZ kindled rats as compared to normal control on day 49 and when LEV was combined with SRT. In EPM test, however none of the drug treatments had any effect on transfer latencies except LEV pretreated kindled group. In Passive avoidance (PA) test, kindling was associated with a significant decrease in retention time(p = 0.018) while LEV and SV had no effect. The PTZ kindled rats showed significantly higher malondialdehyde(MDA) levels in brain hippocampus(p = 0.0286) while both SRT and SV were associated with significantly lower MDA levels as compared to kindled control group. In case of glutathione (GSH), kindling had no significant effect. The use of sertraline for depression in persons with epilepsy on AEDs needs to be carefully evaluated and monitored due to likelihood of individual variation.

Carveol Attenuates Seizure Severity and Neuroinflammation in Pentylenetetrazole-Kindled Epileptic Rats by Regulating the Nrf2 Signaling Pathway.

Epilepsy is a neurodegenerative brain disorder characterized by recurrent seizure attacks. Numerous studies have suggested a strong correlation between oxidative stress and neuroinflammation in several neurodegenerative disorders including epilepsy. This study is aimed at investigating the neuroprotective effects of the natural compound carveol against pentylenetetrazole- (PTZ-) induced kindling and seizure model. Two different doses of carveol (10 mg/kg and 20 mg/kg) were administered to male rats to determine the effects and the effective dose of carveol and to further demonstrate the mechanism of action of nuclear factor E2-related factor (Nrf2) in PTZ-induced kindling model. Our results demonstrated reduced levels of innate antioxidants such as superoxide dismutase (SOD), catalase, glutathione-S-transferase (GST), and glutathione (GSH), associated with elevated lipid peroxidation (LPO) and inflammatory cytokines level such as tumor necrosis factor-alpha (TNF-α), and mediators like cyclooxygenase (COX-2) and nuclear factor kappa B (NFκB). These detrimental effects exacerbated oxidative stress and provoked a marked neuronal alteration in the cortex and hippocampus of PTZ-intoxicated animals that were associated with upregulated Nrf2 gene expression. Furthermore, carveol treatment positively modulated the antioxidant gene Nrf2 and its downstream target HO-1. To further investigate the role of Nrf2, an inhibitor of Nrf2 called all-trans retinoic acid (ATRA) was used, which further exacerbated PTZ toxicity. Moreover, carveol treatment induced cholinergic system activation by mitigating acetylcholinesterase level which is further linked to attenuated neuroinflammatory cascade. The extent of blood-brain barrier disruption was evaluated based on vascular endothelial growth factor (VEGF) expression. Taken together, our findings suggest that carveol acts as an Nrf2 activator and therefore induces downstream antioxidants and mitigates inflammatory insults through multiple pathways. This eventually alleviates PTZ-induced neuroinflammation and neurodegeneration.

PTZ kindling model for epileptogenesis, refractory epilepsy, and associated comorbidities: relevance and reliability.

Pentylenetetrazole (PTZ)-induced seizure is one of the gold standard mouse models for rapid evaluation of novel anticonvulsants. Synchronically, PTZ induced kindling in mice is also a simple and well accepted model of chronic epilepsy. PTZ kindling has been explored for studying epileptogenesis, epilepsy-associated comorbidities, and refractory epilepsy. This review summarizes the potential of PTZ kindling in mice and its modifications for its face, construct, and predictive validity to screen antiepileptogenic drugs, combined or add on novel and safe therapies for treatment of epilepsy-associated depression and cognitive impairment as well as effective interventions for pharmacoresistant epilepsy.

Low-Frequency Stimulation Prevents Kindling-Induced Impairment through the Activation of the Endocannabinoid System.

BACKGROUND: Cannabinoid system affects memory and has anticonvulsant effects in epileptic models. In the current study, the role of cannabinoid 1 (CB1) receptors was investigated in amelioration of the effects of low-frequency stimulation (LFS) on learning and memory impairments in kindled rats. METHODS: Electrical stimulation of the hippocampal CA1 area was employed to kindle the animals. LFS was applied to the CA1 area in four trials following the last kindling stimulation. One group of animals received intraperitoneal injection of AM251 (0.1 µg/rat), a CB1 receptor antagonist, before the LFS application. Similarly, CB1 agonist WIN55-212-2 (WIN) was administrated to another group prior to LFS. The Morris water maze (MWM) and the novel object recognition (NOR) tests were executed 48 h after the last kindling stimulation to assess learning and memory. RESULTS: Applying LFS in the kindled+LFS group restored learning and memory impairments in the kindled rats. There was a significant difference between the kindled and the kindled+LFS groups in learning and memory. The application of AM251 reduced the LFS effects significantly. Adversely, WIN acted similarly to LFS and alleviated learning and memory deficits in the kindled+WIN group. In addition, WIN did not counteract the LFS enhancing effects in the KLFS+WIN group. CONCLUSIONS: Improving effects of LFS on learning and memory impairments are mediated through the activation of the endocannabinoid (ECB) system.

Inhibition of Death-associated Protein Kinase 1 protects against Epileptic Seizures in mice.

Epilepsy is a chronic encephalopathy and one of the most common neurological disorders. Death-associated protein kinase 1 (DAPK1) expression has been shown to be upregulated in the brains of human epilepsy patients compared with those of normal subjects. However, little is known about the impact of DAPK1 on epileptic seizure conditions. In this study, we aim to clarify whether and how DAPK1 is regulated in epilepsy and whether targeting DAPK1 expression or activity has a protective effect against epilepsy using seizure animal models. Here, we found that cortical and hippocampal DAPK1 activity but not DAPK1 expression was increased immediately after convulsive pentylenetetrazol (PTZ) exposure in mice. However, DAPK1 overexpression was found after chronic low-dose PTZ insults during the kindling paradigm. The suppression of DAPK1 expression by genetic knockout significantly reduced PTZ-induced seizure phenotypes and the development of kindled seizures. Moreover, pharmacological inhibition of DAPK1 activity exerted rapid antiepileptic effects in both acute and chronic epilepsy mouse models. Mechanistically, PTZ stimulated the phosphorylation of NR2B through DAPK1 activation. Combined together, these results suggest that DAPK1 regulation is a novel mechanism for the control of both acute and chronic epilepsy and provide new therapeutic strategies for the treatment of human epilepsy.

Antiseizure effects of the cannabinoids in the amygdala-kindling model.

OBJECTIVE: Focal impaired awareness seizures (FIASs) are the most common seizure type in adults and are often refractory to medication. Management of FIASs is clinically challenging, and new interventions are needed for better seizure control. The amygdala-kindling model is a preclinical model of FIASs with secondary generalization. The present study assessed the efficacy of cannabidiol (CBD), ∆9-tetrahydrocannabinol (THC), and a combination of CBD and THC in a 15:1 ratio at suppressing focal and secondarily generalized seizures in the amygdala-kindled rat. METHODS: Fully kindled, male Sprague Dawley rats, with bipolar electrodes implanted in the right amygdala, were given either CBD (0-320 mg/kg), THC (0-40 mg/kg), or a combination of CBD and THC (15:1 ratio, multiple doses) intraperitoneally. Suprathreshold kindling stimulation was administered 1 h (THC) or 2 h (CBD) after drug injection, and outcomes were assessed using focal electroencephalographic recording and the Racine seizure scale. RESULTS: CBD alone produced a partial suppression of both generalized seizures (median effective dose [ED50 ] = 283 mg/kg) and focal seizures (ED40 = 320 mg/kg) at doses that did not produce ataxia. THC alone also produced partial suppression of generalized (ED50 = 10 mg/kg) and focal (ED50 = 30 mg/kg) seizures, but doses of 10 mg/kg and above produced hypolocomotion, although not ataxia. The addition of a low dose of THC to CBD (15:1) left-shifted the CBD dose-response curve, producing much lower ED50 s for both generalized (ED50 = 26 + 1.73 mg/kg) and focal (ED50 = 40 + 2.66 mg/kg) seizures. No ataxia or hypolocomotion was seen at these doses of the CBD + THC combination. SIGNIFICANCE: CBD and THC both have antiseizure properties in the amygdala-kindling model, although THC produces suppression of the amygdala focus only at doses that produce hypolocomotion. The addition of small amounts of THC greatly improves the effectiveness of CBD. A combination of CBD and THC might be useful for the management of FIASs.

Rapamycin alleviates memory deficit against pentylenetetrazole-induced neural toxicity in Wistar male rats.

Numerous studies have reported that epilepsy causes memory deficits. The present study was aimed at studying the effect of rapamycin against the memory deficiency of the pentylenetetrazole (PTZ)-kindled animal model of epilepsy. In the present experiment, we randomly chose thirty male rats from the species of Wistar and categorized them in groups of control and experiment (6 for each group). The groups of experiment received the injection of rapamycin (0.5, 1 and 2 mg/kg) intraperitoneally (i.p.) and the group of control received normal saline (0.9%) treatment. Through the PTZ's sub-threshold dose (35 mg kg-1, i.p.), all groups were kindled 12 times. Passive avoidance test (PAT) was used for gauging the memory function and the seizure behaviors after the kindling procedure. The rodents were sacrificed at the end of the trial and their brains were scooped for measuring the expression of Gabra1 and Pras40 genes. Statistical analysis unveiled that rapamycin delayed the kindling development and the onset of seizures which are tonic-clonic. Moreover, the administration of rapamycin significantly prevented memory dysfunction in epileptic rats. Finally, it was shown that rapamycin resulted in an increase in the expression levels of Gabra1 and Pras40 genes at the brain tissues. The current research design indicated that rapamycin has beneficial effects for the prevention of memory impairment against PTZ-kindling epilepsy in rats. Such promising outcomes could be attributed to its impact on the Gabra1 and Pras40 genes.

Pergularia daemia hydro-ethanolic extract protects against pentylenetetrazole kindling-induced seizures, oxidative stress, and neuroinflammation in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Current antiepileptic drugs fail to control approximately 30% of epilepsies. Therefore, there is a need to develop more effective antiepileptic drugs, and medicinal plants provide an attractive source for new compounds. Pergularia daemia (Asclepiadaceae) is used in Cameroon traditional medicine to treat stroke, anemia, inflammation, and epilepsy. Recently, traditional healers claim that an hydro-ethanolic extract of the roots of P. daemia is more effective than an aqueous extract on refractory seizures. AIM OF THE STUDY: The antiepileptic effect of P. daemia hydro-ethanolic extract was investigated on the pentylenetetrazole kindling model of temporal lobe epilepsy in mice and possible mechanisms of action. MATERIALS AND METHODS: Mice were divided into 8 groups treated as follows: normal group received distilled water (10 ml/kg, p.o.), control group received distilled water (10 ml/kg, p.o.), ethanol group received ethanol (5%, p.o.), positive control received sodium valproate (300 mg/kg, p.o.), and test groups received P. daemia hydro-ethanolic (HE) extract (1.6, 4, 8 and 16 mg/kg, p.o.). All groups were kindled by 11 injections of pentylenetetrazole (PTZ) (35 mg/kg, i.p.), once every alternate day (48 ± 2 h), until the development of kindling, i.e., the occurrence of stage 5 seizures for two consecutive trials. One week later, i.e., 29th day, mice were challenged with a single and lower dose of PTZ (25 mg/kg, i.p.) that does not induce seizures in normal mice but causes seizures in mice prone to seizures and behavioral alterations. After completion of the kindling procedure, Morris water maze, passive avoidance, and open field tests were performed. Afterward, animals were euthanized, and hippocampi were removed for the estimation of the levels of GABA-transaminase (GABA-T), L-glutamate decarboxylase (L-GAD), and γ-aminobutyric acid (GABA). Oxidative stress and neuroinflammation markers also were quantified. Finally, histological analysis of the hippocampus was carried out. RESULTS: PTZ-kindling induced myoclonic jerks and generalized tonic-clonic seizures in control mice. However, the HE extract of P. daemia (4-16 mg/kg), compared to sodium valproate, significantly protected mice against myoclonic jerks and generalized tonic-clonic seizures. Also, the HE extract (1.6-16 mg/kg) significantly increased the seizure score. Furthermore, the HE extract of P. daemia significantly reduced seizure-induced cognitive impairments. PTZ-kindling induced significant alterations in GABA, GABA-T, and L-GAD contents as well as oxidative stress, and neuroinflammation, and the HE extract significantly reversed these effects, suggesting possible mechanisms. All these activities of the HE extract were confirmed by its protective effect against neuronal loss in the hippocampus. CONCLUSIONS: The HE extract of P. daemia protected mice against kindled seizures and cognitive impairments, and these effects were greater than those of sodium valproate, a widely used antiepileptic drug. These effects may be mediated by neuromodulatory, anti-oxidant, and anti-inflammatory activities, thus suggesting a neuroprotective effect. These findings help to explain the beneficial use of these HE extracts of P.daemia in traditional medicine to treat epilepsy in Cameroon.

Examination of the antiepileptic effects of valacyclovir using kindling mice- search for novel antiepileptic agents by drug repositioning using a large medical information database.

Despite the availability of more than 20 clinical antiepileptic drugs, approximately 30% of patients with epilepsy do not respond to antiepileptic drug treatment. Therefore, it is important to develop antiepileptic products that function via novel mechanisms. In the present study, we evaluated data from one of the largest global databases to identify drugs with antiepileptic effects, and subsequently attempted to understand the effect of the combination of antiepileptic drugs and valacyclovir in epileptic seizures using a kindling model. To induce kindling in mice, pentylenetetrazol at a dose of 40 mg/kg was administered once every 48 h. Valacyclovir was orally administered 30 min before antiepileptic drug injection in kindled mice, and behavioral seizures were monitored for 20 min following pentylenetetrazol administration. Additionally, c-Fos expression in the hippocampal dentate gyrus was measured in kindled mice. Valacyclovir showed inhibitory effects on pentylenetetrazol-induced kindled seizures. In addition, simultaneous use of levetiracetam and valacyclovir caused more potent inhibition of seizure activity, and neither valproic acid nor diazepam augmented the anti-seizure effect in kindled mice. Furthermore, kindled mice showed increased c-Fos levels in the dentate gyrus. The increase in c-Fos expression was significantly inhibited by the simultaneous use of levetiracetam and valacyclovir. The findings of the present study indicate that a combination of levetiracetam and valacyclovir had possible anticonvulsive effects on pentylenetetrazol-induced kindled epileptic seizures. These results suggest that valacyclovir may have an antiseizure effect in patients with epilepsy.

Anti-Seizure Activity of 1-Adamantane Carboxylic Acid in Common Experimental Seizure Models: Role of Benzodiazepine-GABAA Receptors.

BAckground: Despite introduction of modern antiepileptic drugs, 30% of epileptic patients are still drug resistant. Remarkable three-dimensional spatial structure of 1-Adamantane carboxylic acid (AdCA), yet the simplicity of the molecule, makes AdCA a promising lead compound. Methods: Sedative/motor impairment and 24-h mortality rate of AdCA were determined in mice. Impact of AdCA on (1) threshold and occurrence of clonic seizures induced by pentylenetetrazole (PTZ) in mice, (2) incidence of tonic seizures induced by maximal electroshock (MES) in mice, and (3) incidence of generalized seizures and duration of evoked afterdischarges in amygdala-kindled rats, were determined. The role of benzodiazepine receptors in the AdCA effect on clonic seizure threshold was also assessed. Results: AdCA showed sedative effect (median toxic dose [TD50] = 224.5 [190.2-289.9] mg/kg). Median lethal dose (LD50) = 805.5 (715.2­988.1) mg/kg was obtained for AdCA. The compound increased PTZ seizure threshold from 180 mg/kg (p < 0.05) and also inhibited the incidence of clonic seizures (ED50 = 256.3 [107.4-417.3] mg/kg). AdCA also decreased afterdischarge duration (p < 0.01) and the incidence of generalized seizures (ED50 < 50 mg/kg) in the kindled rats. However, AdCA did not protect mice against tonic seizures induced by MES. The benzodiazepine receptor antagonist flumazenil prevented the increase of seizure threshold by AdCA. Conclusion: AdCA possesses anticonvulsant activity in kindling and PTZ models through the activation of benzodiazepine/GABAA receptors with acceptable therapeutic index.

Dysregulation of REV-ERBα impairs GABAergic function and promotes epileptic seizures in preclinical models.

To design potentially more effective therapies, we need to further understand the mechanisms underlying epilepsy. Here, we uncover the role of Rev-erbα in circadian regulation of epileptic seizures. We first show up-regulation of REV-ERBα/Rev-erbα in brain tissues from patients with epilepsy and a mouse model. Ablation or pharmacological modulation of Rev-erbα in mice decreases the susceptibility to acute and chronic seizures, and abolishes diurnal rhythmicity in seizure severity, whereas activation of Rev-erbα increases the animal susceptibility. Rev-erbα ablation or antagonism also leads to prolonged spontaneous inhibitory postsynaptic currents and elevated frequency in the mouse hippocampus, indicating enhanced GABAergic signaling. We also identify the transporters Slc6a1 and Slc6a11 as regulators of Rev-erbα-mediated clearance of GABA. Mechanistically, Rev-erbα promotes the expressions of Slc6a1 and Slc6a11 through transcriptional repression of E4bp4. Our findings propose Rev-erbα as a regulator of synaptic function at the crosstalk between pathways regulating the circadian clock and epilepsy.

Fenofibrate protects the neurovascular unit and ameliorates plasma corticosterone levels in pentylenetetrazole-induced kindling seizure in mice.

Epileptic seizures are the most common neurological diseases that change the function of neurovascular unit at molecular levels accompanied by activation of a wide variety of neurodegenerative cascades. Based on the pleiotropic functions of peroxisome proliferator-activated receptor-alpha (PPARα), the current study evaluated the neuroprotective effects of fenofibrate (an effective PPARα agonist) on the brain injuries induced by pentylenetetrazole (PTZ)-induced kindling seizure. Adult male NMRI mice were randomly assigned into four groups (n = 14) as follows; control, untreated kindled mice (PTZ) and two fenofibrate-treated kindled groups. Repeated intraperitoneal injections of PTZ (45 mg/kg) were used to develop kindling seizure every 48 h for 21 days. Treated mice were administered orally fenofibrate at doses of 30 and 50 mg/kg/day during the study. Plasma corticosterone and brain levels of brain-derived neurotrophic factor (BDNF), malondialdehyde (MDA) and mRNA transcription of p53, as well as blood-brain barrier (BBB) permeability, were determined at termination of the study. Fenofibrate considerably improved seizure latency and anxiety-like behaviors in treated kindled mice. Fenofibrate at doses of 30 and 50 mg/kg significantly (P < 0.001) decreased plasma corticosterone (56.88 ± 0.80 and 54.81 ± 0.29 ng/mL, respectively) compared to PTZ group (74.96 ± 1.60 ng/mL). It also significantly (P < 0.05) decreased BDNF levels in both treatment groups (8.13 ± 0.14 and 8.74 ± 0.09 ng/mL, respectively) compared to PTZ group (9.68 ± 0.20 ng/mL). Fenofibrate particularly at higher dose significantly (P < 0.01) decreased MDA content and mRNA expression levels of p53 in treated kindled mice by 67% and 28%, respectively, compared to PTZ group. Similarly, 50 mg/kg fenofibrate significantly (P < 0.05) decreased Evans blue extravasation into brain in treated kindled mice (8.72 ± 0.96 µg/g) compared to PTZ group (15.31 ± 2.18 µg/g). Our results revealed the anticonvulsive and neuroprotective effects of fenofibrate in PTZ-induced kindling seizure in mice. Fenofibrate also improved the neurovascular functions at molecular levels in kindling seizure that might be associated with ameliorating the seizure behaviors.

[Effects of Histamine and Related Compounds on the Central Nervous System].

There has been little information about the role of histamine on the central nervous system (CNS), different from dopamine and serotonin. In the present study, therefore, the effects of histamine and related compounds on the CNS were studied using rats. Intracerebroventricular (i.c.v.) injection of histamine and 2-methylhistamine ameliorated memory deficit after long interrution of learning in active avoidance response. First generation H1-antagonists inhibited active avoidance response, whereas newly develpoed H1-antagonists showed little effect. α-Fluoromethylhistidine, an histidine decarboxylase inhibitor, also inhibited active avoidance response. In radial maze performance, almost the same findings were obtained. I.c.v. injection of histamine and H1-agonists inhibited amygdaloid kindled seizures. First generation H1-antagonists attenuated histamine-induced inhibition of amygdaloid kindled seizures. Both i.c.v. and intraperitoneal injections of H3-antagonist, thioperamide, resulted in a dose-related inhibition of amygdaloid kindled seizures. The effect of thioperamide was inhibited by an H3-agonists and H1-antagonists. Similar to nitrazepam, diphenhydramine and chlorpheniramine caused a shortening of sleep latency. On the other hand, no significant effects were observed with second generation H1-antagonists. These findings suggest that histamine plays an important role in learning and memory via H1-receptors, an inhibition of amygdaloid kindled seizures induced by histamine occurred through not only H1-receptors but also H3-receptors, and that classic H1-antagonists can be useful as a effective hypnotic for difficulty in falling asleep.

Neuroprotective role of chrysin-loaded poly(lactic-co-glycolic acid) nanoparticle against kindling-induced epilepsy through Nrf2/ARE/HO-1 pathway.

Chrysin is the major bioactive compound of blue passionflower, an important medicinal plant used in traditional herbal formulations since ancient times. In the present study, we report that chrysin nanoparticles (chrysin NPs) protect Wistar rats against kindling-induced epilepsy. Nanoparticles of sizes less than 150 nm with a spherical shape were prepared using poly(d,l-lactic-co-glycolic acid) and polyvinyl alcohol, respectively, as polymer and stabilizer. Rats were injected with subconvulsive doses of pentylenetetrazole (PTZ) (35 mg/kg, intraperitoneal) every second day, with 22 injections in total, and on the same days, they received protective doses of the chrysin NPs (5 and 10 µg/mL, PO), respectively, 45 min before each PTZ injection. After the last PTZ injection, an average of thirteen seizure scores was recorded. Animals were killed by decapitation 24 h after a seizure. The cortex and hippocampus were removed and stored in liquid nitrogen for determining oxidative stress terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, histopathology, and reverse transcription-polymerase chain reaction for messenger RNA expression. The result showed chrysin NPs treatment has counteracted oxidative stress, reduced neuronal apoptosis, and upregulated nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NAD(P)H quinone oxidoreductase 1. In conclusion, our findings demonstrate that the neuroprotective effect of chrysin NPs against kindling-induced epilepsy might be escorted by the alleviation of oxidative stress through the Nrf2/antioxidant response element/HO-1 pathway signal pathway.

Lacosamide improves biochemical, genotoxic, and mitochondrial parameters after PTZ-kindling model in mice.

This study evaluated the effect of lacosamide (LCM) on biochemical and mitochondrial parameters after PTZ kindling in mice. Male mice were treated on alternative days for a period of 11 days with LCM (20, 30, or 40 mg/kg), saline, or diazepam (2 mg/kg), before PTZ administration (50 mg/kg). The hippocampi were collected to evaluate free radicals, the activities of superoxide dismutase (SOD), catalase (CAT), and the mitochondrial complexes I-III, II, and II-III, as well as Bcl-2 and cyclo-oxygenase-2 (COX-2) expressions. Hippocampi, blood, and bone marrow were collected for genotoxic and mutagenic evaluations. LCM 40 mg/kg increased latency and decreased percentage of seizures, only on the 3rd day of observation. The dose of 30 mg/kg only showed positive effects on the percentage of seizures on the 2nd day of observation. LCM decreased free radicals and SOD activity and the dose of 40 mg/kg were able to increase CAT activity. LCM 30 and 40 mg/kg improved the enzymatic mitochondrial activity of the complex I-III and LCM 30 mg/kg improved the activity of the complex II. In the comet assay, the damage induced by PTZ administration was reduced by LCM 20 and 30 mg/kg. The dose of 20 mg/kg increased COX-2 expression while the highest dose used, 40 mg/kg, was able to reduce this expression when compared to the group treated with LCM 20 mg/kg. Although LCM did not produce the antiepileptogenic effect in vivo, it showed the neuroprotective effect against oxidative stress, bioenergetic dysfunction, and DNA damage induced by the repeated PTZ administration.

Cognition and memory impairment attenuation via reduction of oxidative stress in acute and chronic mice models of epilepsy using antiepileptogenic Nux vomica.

Ethnopharmacological relevance Processed Nux vomica seed extracts and homeopathic medicinal preparations (HMPs) are widely used in traditional Indian and Chinese medicine for respiratory, digestive, neurological and behavioral disorders. Antioxidant property of Nux vomica is well known and recent investigation has highlighted the anticonvulsant potential of its homeopathic formulation. AIM OF THE STUDY: To explore the anticonvulsant and antiepileptogenic potential of Nux vomica HMPs (6CH, 12CH and 30CH potency) in pentylenetetrazole (PTZ) induced acute and chronic experimental seizure models in mice and investigate their effects on cognition, memory, motor activity and oxidative stress markers in kindled animals. MATERIALS AND METHODS: Acute seizures were induced in the animals through 70 mg/kg (i.p.) administration of PTZ followed by the evaluation of latency and duration of Generalized tonic-clonic seizures (GTCS). Subconvulsive PTZ doses (35 mg/kg, i.p.) induced kindling in 29 days, which was followed by assessment of cognition, memory and motor impairment through validated behavioral techniques. The status of oxidative stress was estimated through measurement of MDA, GSH and SOD. RESULTS: HMPs delayed the latency and reduced the duration of GTCS in acute model signifying possible regulation of GABAergic neurotransmission. Kindling was significantly hindered by the HMPs that justified the ameliorated cognition, memory and motor activity impairment. The HMPs attenuated lipid peroxidation by reducing MDA level and strengthened the antioxidant mechanism by enhancing the GSH and SOD levels in the kindled animals. CONCLUSIONS: Nux vomica HMPs showed anticonvulsant and antiepileptogenic potency in acute and chronic models of epilepsy. The test drugs attenuated behavioral impairment and reduced the oxidative stress against PTZ induced kindling owing to which they can be further explored for their cellular and molecular mechanism(s).

Diazepam and electrical stimulation of paleocerebellar cortex inhibits seizures in pentylenetetrazol­kindled rats.

The cerebellum is a potent anti­epileptic target for deep brain stimulation in patients with drug­resistant epilepsy. The effects of such stimulation, however, may also favor seizure activity. Our goal was to investigate the effect of cerebellar electrical stimulation (ES) alone and in combination with the anti­epileptic drug diazepam (DIA) on seizure outcome. We used a rat model of pentylenetetrazol kindling, which is characterized by seizures followed by deteriorations in central benzodiazepine­GABAA (BDZ­GABAA) receptors. We tested the effects of ES alone and in combination with DIA (0.1 and 1.0 mg/kg) on seizures. Our data demonstrated: 20 ES trials can prevent the recurrence of clonic­tonic kindled seizures, administration of either DIA­0.1 or ES (5 trials) alone is ineffective on seizures, and combining DIA­0.1 and 5 ES or DIA­1.0 and 5 ES caused an additive effect, prolonged the latency to seizure onset, and prevented recurrence of clonic­tonic seizures. We also observed that ES alone produced either facilitation or inhibition of seizures on EEG. In contrast, the same ES inhibited EEG seizures when delivered after a combination of DIA­1.0 and 5 ES and ultimately prevented the facilitation of the discharges. Lastly, we demonstrated that seizure suppression is intensified when cortical ES is performed after DIA administration. Our data supported the hypothesis that both BDZ­GABAA receptor activity along with cerebellar output comprise the potential mechanisms underlying the peculiar effects of deep brain stimulation in the cerebellum on seizures.