Administration Of Pentylenetetrazol Research Articles

Additive Anticonvulsive Effects of Sumatriptan and Morphine on Pentylenetetrazole-Induced Clonic Seizures in Mice.

Sumatriptan protects the brain from damage and enhance the anti-seizure effect of morphine. There is evidence that nitric oxide (NO) may mediate these effects of both drugs. In the present study, we investigated the effects of sumatriptan (0.1-20 mg/kg, intraperitoneal [i.p.]) and morphine (0.1-20 mg/kg, i.p.) alone or in combination on seizure thresholds in an in vivo model of seizure in mice. Using various NO synthase inhibitors as well as the NO precursor, we assessed possible involvement of NO signaling in these effects. Clonic seizures were induced in male Naval Medical Research Institute mice by intravenous administration of pentylenetetrazol (PTZ). Acute sumatriptan administration exerted anti-convulsive effects at 0.5 (p<0.01) and 1 mg/kg (p<0.05), but pro-convulsive effects at 20 mg/kg (p<0.05). Morphine had anti-convulsive effects at 0.5 (p<0.05) and 1 mg/kg (p<0.001), but exerted pro-convulsive effect at 20 mg/kg (p<0.05). Combination treatment with sub-effective doses of sumatriptan (0.1 mg/kg) and morphine (0.1 mg/kg) significantly (p<0.05) exerted an anti-convulsive effect. Co-administration of the NO precursor L-arginine (60 mg/kg) with sub-effective doses of sumatriptan and morphine significantly (p<0.05) increased seizure threshold compared with sumatriptan alone, but not sumatriptan+morphine group. While concomitant administration of either the non-selective NO synthase (NOS) inhibitor L-NG-nitroarginine methyl ester (5 mg/kg) or the selective inducible NOS inhibitor aminoguanidine (50 mg/kg) with combined sub-effective doses of morphine and sumatriptan produced significant anticonvulsive effects, concomitant administration with the selective neuronal NOS inhibitor 7-nitroindazole (30 mg/kg) inhibited this effect. Our data suggest a possible role for the NO signaling in the anticonvulsive effects of combined sumatriptan and morphine on the PTZ-induced clonic seizures in mice.

Scorpion venom heat-resistant synthesized peptide ameliorates epileptic seizures and imparts neuroprotection in rats mediated by NMDA receptors

Finding new and effective natural products for designing antiepileptic drugs is highly important in the scientific community. The scorpion venom heat-resistant peptide (SVHRP) was purified from Buthus martensii Karsch scorpion venom, and subsequent analysis of the amino acid sequence facilitated the synthesis of a peptide known as scorpion venom heat-resistant synthesis peptide (SVHRSP) using a technique for peptide synthesis. Previous studies have demonstrated that the SVHRSP can inhibit neuroinflammation and provide neuroprotection. This study aimed to investigate the antiepileptic effect of SVHRSP on both acute and chronic kindling seizure models by inducing seizures in male rats through intraperitoneal administration of pentylenetetrazole (PTZ). Additionally, an N-methyl-D-aspartate (NMDA)-induced neuronal injury model was used to observe the anti-excitotoxic effect of SVHRSP in vitro. Our findings showed that treatment with SVHRSP effectively alleviated seizure severity, prolonged latency, and attenuated neuronal loss and glial cell activation. It also demonstrated the prevention of alterations in the expression levels of NMDA receptor subunits and phosphorylated p38 MAPK protein, as well as an improvement in spatial reference memory impairment during Morris water maze (MWM) testing in PTZ-kindled rats. In vitro experiments further revealed that SVHRSP was capable of attenuating neuronal action potential firing, inhibiting NMDA receptor currents and intracellular calcium overload, and reducing neuronal injury. These results suggest that the antiepileptic and neuroprotective effects of SVHRSP may be mediated through the regulation of NMDA receptor function and expression. This study provides new insight into therapeutic strategies for epilepsy.

Antiseizure effects of Lilii Bulbus on pentylenetetrazol kindling-induced seizures in mice: Involvement of Reelin, Netrin-1, and semaphorin

Lilii Bulbus (Lilium lancifolium Thunberg) has a proneurogenic effect on the hippocampus. However, its effects on epilepsy and associated pathological features remain unknown. In this study, we investigated the antiseizure effects of a water extract of Lilii Bulbus (WELB) in mouse model of pentylenetetrazol (PTZ)-induced seizure. Mice were injected with PTZ once every 48 h until full kindling was achieved. WELB (100 and 500 mg/kg) was orally administered once daily before PTZ administration and during the kindling process. We found that WELB treatment protected against PTZ-induced low seizure thresholds and high seizure severity. Further, WELB-treated mice showed attenuated PTZ kindling-induced anxiety and memory impairment. Immunostaining and immunoblots showed that hyperactivation and ectopic migration of dentate granule cells (DGCs) were significantly reduced by WELB treatment in PTZ kindling-induced seizure mice. Staining for mossy fiber sprouting (MFS) using Timm staining and ZnT3 showed that WELB treatment significantly decreased PTZ kindling-induced MFS. Furthermore, the increased or decreased expression of proteins related to ectopic DGCs (Reelin and Dab-1), MFS (Netrin-1, Sema3A, and Sema3F), and their downstream effectors (ERK, AKT, and CREB) in the hippocampus of PTZ kindling mice was significantly restored by WELB treatment. Overall, our findings suggest that WELB is a potential antiseizure drug that acts by reducing ectopic DGCs and MFS and modulating epileptogenesis-related signaling in the hippocampus.

Anticonvulsant Effects and Histopathological Changes in the Hippocampus of Pentylenetetrazole (PTZ)-induced Epileptic Mice Model following Mentat Treatment

Abstract Background: Epilepsy is a neurological illness that disturbs the central nervous system and is characterized by regular convulsions. Over 70 million people worldwide are thought to have epilepsy, with the prevalence rate estimated to be around 1%. Aims: The objective of this study was to assess antiepileptic activities and histological changes after Mentat administration in the hippocampus of pentylenetetrazole (PTZ)-induced seizure mice. Materials and Methods: Twenty Swiss albino mice (18–28 g) were divided into four groups (n = 5) and were given the following intraperitoneally, 2 ml/kg distilled water and 50 mg/kg PTZ to Groups 1 and 2 animals, respectively. Groups 3 and 4 animals were given 200 mg/kg and 400 mg/kg of Mentat, respectively, 1 h before the administration of PTZ and were observed for 300 s. After the experiment, all surviving animals in the various groups were humanely sacrificed and the brains were harvested and preserved in 10% buffered formalin. The brain tissues were processed using routine histological procedures and stained with hematoxylin and eosin. Results: Results of this revealed that Mentat was able to delay the onset time of seizure and offered quantal protection to the animals. Mentat also showed a dose-dependent ameliorative effect against histological changes following PTZ administration in mice. Conclusion: Mentat attenuates PTZ-induced seizure in mice.

Quercetin Exerts Anticonvulsant Effect through Mitigation of Neuroinflammatory Response in Pentylenetetrazole-induced Seizure in Mice.

Epilepsy is a chronic disease of the brain characterized by seizures. The currently available anticonvulsants only treat symptoms with serious adverse drug reactions. Therefore, there is need for new therapeutic intervention that will prevent epileptogenesis with greater therapeutic success. Quercetin (QT) is a flavonoid with known neuroprotective and anti-inflammatory properties. The study aimed to investigate its effects against pentylenetetrazole (PTZ)-induced seizures. Animals were divided into four groups (n = 10). Group 1(control) only received vehicle (10 mL/kg), group 2 received vehicle, groups 3 and 4 received QT 12.5 mg/kg and 25 mg/kg respectively. Sixty minutes after treatments, animals in groups 2 to 4 were injected with sub-convulsive dose of pentylenetetrazole (35 mg/kg, i.p.) on every alternate day (48±2h) for 21 days. The mice were observed for 30 minutes after each PTZ injection for seizure activity. Brain samples were collected for biochemical assays. Administration of PTZ caused significant increase in the intensity of seizures, neuronal degeneration and level of proinflammatory cytokines in animals compared to control. These behavioural alterations were attenuated significantly by QT (12.5 and 25 mg/kg). The PTZ-induced increase in IL-12, TNF-α and IFN-ɣ were significantly reduced by pre-treatment with the QT (12.5 and 25 mg/kg, p.o). Quercetin also reduced neuronal loss compared to control. Quercetin attenuates seizures in kindled mice and reduces neuroinflammation and neurodegeneration. This neuroprotective effect may be attributed to its ability to inhibit inflammatory mediators in the brain.

COMORBID DISORDERS OF THE SLEEP CYCLE – AWAKENESS IN KINDLING RATS UNDER THE CONDITIONS OF USING THE H₃ RECEPTOR ANTAGONIST PITOLISANT

Studies of the neuropathophysiological mechanisms of chronic epileptic activity, whicharise with the participation of the endogenous histaminergic system of the brain, allowus to justify effective complex means of controlling both convulsive manifestations andcomorbid states, which include sleep and wakefulness disorders.Aim of the work – to study the characteristics of the sleep-wake cycle in rats with PTZinduced kindling under the condition of using the H3 receptor antagonist pitolisant.Methods. The kindling syndrome was induced in Wistar rats by daily administration ofpentylenetetrazole (PTZ) (35.0 mg/kg, i. p.) for three weeks. In rats in the course of kindlingdevelopment, pitolisant (5,0 mg/kg, i. p.) was used for 30 min before epileptogen administration.Research results. In rats with developed kindling, the paradoxical sleep phase wasreduced to 7,1% of the total observation period (4 hours) and its fragmentation increased39,7% and the latent period of paradoxical sleep was 24,0% less compared to the controlgroup (P&lt;0,05). Pitolizant treatment was accompanied by an increase in the durationof the awake phase, which was 29% of the total observation time (P&gt;0,05). At the sametime, the duration of paradoxical sleep was 11,6% (P&gt;0,05), and the slow-wave sleepphase was 71,0% (P&gt;0,05). The number of sleep-wake cycles unreliably exceeded theindicator in the control group 17,2% (P&gt;0,05). Latent periods of falling asleep exceededthe indicator in the control group 44,1% (P&lt;0,05) and at the same time was higher thanin kindling rats 60,2% (P&lt;0,05). The latency period of paradoxical sleep was 34.2%higher than kindling rats (P&lt;0.05). &#x0D; Conclusions. The formation of PTZ-kindling is accompanied by a reduction in the latent period of emergence and the total duration of the paradoxical phase of sleep, as well as an increase in its fragmentation. Blocking of H3 histamine receptors by pitolisan during the formation of kindling by administration of pentylenetetrazol prevents the occurrence of wake-sleep cycle disorders.

Neuroprotective Effect of Chlorogenic Acid against Pentylenetetrazol Induced Kindled Epilepsy in Mice

Background: Epilepsy is a group of chronic neurological disorders characterized by seizures. Kindling, a chronic epileptic mouse model that was used to explore the epileptogenic mechanism and seeking new anti-epileptics. In kindling, sub-convulsive (chemical/ electrical) stimuli are delivered repeatedly and erratically, eventually causes massive convulsions. The aim of this study was to investigate the neuroprotective effects of chlorogenic acid, a phenolic acid derived from coffee, on seizure severity and kindling progression. Memory impairment inflammation due to oxidative stress by pentylenetetrazol (PTZ). Objective: This study was used to investigate the neuroprotective effect of chlorogenic acid against pentylenetetrazol induced kindled epilepsy in mice. Methods: Kindling was provoked by subsequent (one-day-gap) injections of PTZ (subconvulsive; 35 mg/kg; s.c.) for 29 days in mice. The experimental protocol included six groups (n=6) receiving proconvulsant doses of PTZ (35 mg/kg i.p.) every other day for 31 days. Alternating subcutaneous injections of PTZ induced priming with 15 injections of PTZ. Compared with the PTZ group, pre-treatment with chlorogenic acid (5 and 10 mg/kg) 1 h before PTZ administration reduced seizure score, reduced metastasis latency due to increased normal maze, and decreased metastasis latency extension at FST. PTZ-induced biochemical changes were enhanced in chlorogenic acid-treated animals, as indicated by decreased lipid peroxidation (MDA), nitric oxide and AChE levels, and increased SOD, GSH, catalase level. Following PTZ injection, convulsive behaviours were noted for 30 minutes. Open-field-test (locomotor activity), force swimming test (depressive behaviors), elevated plus-maze and passive avoidance tests were employed to evaluate cognition. Brain homogenate was used to estimate oxidative stress (glutathione,superoxide-dismutase, lipid-peroxidation), and acetylcholinesterase activity. Results: This result suggest the neuroprotective potential of chlorogenic acid. This may be correlated with its ability to inhibit oxidative damage and reduce the occurrence of seizures and other related damage. It may be a promising candidate for mitigating the consequences of events. Conclusion: Our findings suggest effect of chlorogenic acid against pentylenetetrazol-induced kindled epilepsy in mice which were established by behavioral and biochemical paradigms

(-)-α-bisabolol exerts neuroprotective effects against pentylenetetrazole-induced seizures in rats by targeting inflammation and oxidative stress

Epilepsy is the most common neurological disorder which is accompanied with behavioral and psychiatric alternations. Current evidences have shown that (-)-α-bisabolol (BSB) possess anti-inflammatory and antioxidative effects in several animal studies. Here, we conducted present study to evaluate its neuroprotective effects against pentylenetetrazole (PTZ)-induced seizures in rats. We used fifty male rats and they were randomly assigned into 5 groups control, BSB100, PTZ, BSB50 + PTZ, BSB100 + PTZ. The animals intraperitoneally received PTZ (45 mg/kg) for ten consecutive days to induce epilepsy model. BSB in doses of 50 and 100 mg/kg was administrated orally one hour before PTZ administration for ten days. The elevated plus maze (EPM) test was carried out to assess anxiety-like behavior. The seizure intensity was evaluated according to modifies Racine's convulsion scale (RCS). Y-maze and passive avoidance were utilized to assess working memory and aversive memory. The expression of pro-inflammatory cytokines and oxidative stress factors were measured using the enzyme-linked immunosorbent assay (ELISA). The neuronal cell loss in the hilar region was assessed using Nissl staining. Results showed that PTZ-treated rats had more seizure intensity, anxiety-like behavior, memory deficits, higher levels of TNF-α, IL-1β, and oxidative markers. Pre-treatment with BSB 100 significantly inhibited seizure intensity, anxiety-like behavior, and memory deficits; reduced levels of TNF-α, IL-1β, and MDA oxidative markers. Collectively, outcome of this work shows that BSB at the dose of 100 mg/kg may exert neuroprotective effects by mitigating seizures, oxidative stress, and neuroinflammation, and ameliorates memory and anxiety disorders in the PTZ-induced seizure rats.

Suppressive Effects of Docosahexaenoic Acid Intake on Increased Seizure Susceptibility after Growth Due to Febrile Seizures in Infancy.

Febrile seizures are seizures accompanied by a fever and frequently occur in children six months to five years of age. Febrile seizures are classified as simple or complex, and complex febrile seizures increase the risk of temporal lobe epilepsy after growth. Therefore, it is important to interfere with epileptogenesis after febrile seizures to prevent post-growth epilepsy. The present study challenged nutritional intervention using docosahexaenoic acid (DHA). Febrile seizures were induced in mice at the age of 10 d using a heat chamber, and seizure sensitivity was examined using pentylenetetrazol (PTZ) administration after growth. PTZ increased the seizure score and shortened the latency in the complex febrile seizure group compared to the control, hyperthermia and simple febrile seizure groups. Mice in the complex febrile seizure group showed abnormal electroencephalograms pre- and post-PTZ administration. Therefore, seizure susceptibility increases the episodes of complex febrile seizures. DHA supplementation after febrile seizures clearly suppressed the increased seizure susceptibility due to complex febrile seizures experienced in infancy. DHA also attenuated microglial activation after complex febrile seizures. Taken together, DHA suppressed microglial activation following complex febrile seizures, which may contribute to protecting the brain from post-growth seizures. The intake of DHA in infancy may protect children from high fever-induced developmental abnormalities.

Evaluation of the anticonvulsant activity of ethanol leaf extract of Panicum maximum in pentylenetetrazole and strychnine induced seizure in mice.

Epilepsy is a chronic neurological condition affecting around 50 million people worldwide. This study evaluated the anticonvulsant effect of Panicium maxmium in pentylenetetrazole (PTZ) and strychnine (STN) induced convulsions in mice. For each model, 25 mice were divided into five groups; group 1 received 10 ml/kg distilled water, groups 2-4 received 100 mg/kg, 200 mg/kg and 400 mg/kg of extract p.o respectively. Group 5 received 3 mg/kg of diazepam p.o. Convulsion was induced intraperitoneally using PTZ and STN, thirty minutes after the extract was administered. The onset of myoclonic, tonic-clonic seizure, time of death within 60 minutes of PTZ and STN administration were monitored. Data were statistically analyzed using one-way ANOVA followed by Dunnet’s comparison tests. In STN-induced seizure model, 100 mg/kg of P. maximum exhibited a significant (p &lt; 0.001) anticonvulsant activity by delaying myoclonic seizure onset in mice when compared to the control. Significant (p &lt; 0.001) activity was also observed in the onset of tonic clonic seizure at same dose when compared to control. In PTZ-induced seizure model, 200 mg/kg exhibited more significant (p &lt; 0.001) activity followed by 100 mg/kg (p &lt; 0.05) by delaying myoclonic seizure onset in mice when compared to the control. Significant (p &lt; 0.001) activity were observed in tonic clonic phase at same doses respectively. The different doses administered couldn’t protect the mice from death. Diazepam, standard drug used, protected all the animals without any signs of convulsions. The results provide evidence that the extract possesses anticonvulsant activity.

Parvalbumin neurons in the anterior nucleus of thalamus control absence seizures.

Anterior nucleus of thalamus (ANT) has been widely accepted as a potential therapeutic target for drug-resistant epilepsy. Although atrophy of the ANT was also reported in patients with absence epilepsy, the relationship between the ANT and absence epilepsy has been barely illustrated. Using chemogenetics, we evaluated the effect of ANT parvalbumin (PV) neurons on pentylenetetrazole (PTZ)-induced absence seizures in mice. We found that intraperitoneal injection of PTZ (30 mg/kg) can stably induce absence-like seizures characterized by bilaterally synchronous spike-wave discharges (SWDs). Selective activation of PV neurons in the ANT by chemogenetics could aggravate the severity of absence seizures, whereas selective inhibition of that cannot reverse this condition and even promote absence seizures as well. Moreover, chemogenetic inhibition of ANT PV neurons without administration of PTZ was also sufficient to generate SWDs. Analysis of background EEG showed that chemogenetic activation or inhibition of ANT PV neurons could both significantly increase the EEG power of delta oscillation in the frontal cortex, which might mediate the pro-seizure effect of ANT PV neurons. Our findings indicated that either activation or inhibition of ANT PV neurons might disturb the intrinsic delta rhythms in the cortex and worsen absence seizures, which highlighted the importance of maintaining the activity of ANT PV neurons in absence seizure.

Neuroprotective effect of Berberine Nanoparticles Against Seizures in Pentylenetetrazole Induced Kindling Model of Epileptogenesis: Role of Anti-Oxidative, Anti-Inflammatory, and Anti-Apoptotic Mechanisms.

There is an unmet need to develop alternative therapeutic strategies to not only restrain seizures but also to alleviate the underlying pathologies and sequelae. Berberine (BBR), an isoquinoline alkaloid, has shown promising effect in the kindling model of epileptogenesis, but due to the poor oral bioavailability its clinical application is limited. So, the present study was designed to study the neuroprotective effect of BBR nanoparticles (enhanced bioavailability as compared to BBR) against seizures in pentylenetetrazole (PTZ) induced kindling model of epileptogenesis. Kindling model was established in male Wistar rats by intraperitoneal (i.p.) administration of PTZ (30mg/kg) on every alternate day till the animal became fully kindled or till 6weeks. Three doses of BBR (50, 100, and 200mg/kg) and nano-BBR (25, 50, 100mg/kg) were studied for seizure score, percentage of animal kindled, histopathological score, oxidative stress, inflammation, and apoptosis in PTZ treated rats by conducting cytokines, gene expression and protein expression analysis. BBR nanoparticles showed significant effect on the seizure score and percentage of animal kindled, histopathological score, neurobehavioral parameters (Forced swim test, Rotarod), oxidative (MDA, SOD, GSH, GPx) and inflammatory (IL-1beta, TNF-alpha) parameters, apoptotic parameters (Bax and iNOS), and gene (Nrf2, NQO1, HO1) and protein expression (Nrf2) as compared to both PTZ and BBR. BBR nanoparticles showed neuroprotective effect in PTZ induced kindling model of epileptogenesis and proves to be a promising antiepileptogenic therapy for the patients who are at high risk of developing seizures.

Effect of Rosiglitazone, the Peroxisome Proliferator-Activated Receptor (PPAR)-γ Agonist, on Apoptosis, Inflammatory Cytokines and Oxidative Stress in pentylenetetrazole-Induced Seizures in Kindled Mice.

A growing body of evidence has shown that seizure can trigger inflammatory cascades through increasing the expression of several inflammatory cytokines. It has been proved that peroxisome proliferator-activated receptor-γ agonists have immunomodulatory, anti-inflammatory, and neuroprotective effects beyond the putative hypoglycemic effects. Thus, we investigated the inhibitory effect of rosiglitazone on the development of pentylenetetrazol (PTZ)-induced kindling via affecting the inflammatory pathway. Male C57BL/6 mice were randomly divided into vehicle group (0.1% DMSO), PTZ-group and rosiglitazone-PTZ-group. Kindling was induced by the administration of PTZ (40mg/kg, i.p) every other day and mice were observed for 20min after each PTZ injection. Twenty-four hours after the last dose, animals were euthanized and hippocampus was isolated. The level of Malondialdehyde (MDA), Superoxide Dismutase (SOD), and Catalase (CAT) activity were quantified in hippocampus by biochemical methods. The protein levels of IL-1β, IL-6, IL-10, IFN-γ, TNF-α, caspase-3, iNOS, PPAR-γ, Bcl-2, or Bax factors were measured with western blotting. Also, the quantitative real-time PCR were used to evaluate the mRNA expression of those factors. Pretreatment with rosiglitazone significantly prevented the progression of kindling in comparison with control group. The rosiglitazone significantly decreased the MDA level and increased the CAT, and SOD levels in the rosiglitazone treated mice compared to those in the PTZ group (P < 0.01). Using real-time PCR and Western blotting assay, similar results were obtained. The expression levels of IL-1β, IL-6, IL-10, IFN-γ, TNF-α, Bax or PPAR-γ were significantly changed in the brain. The results of this study suggest that effect of rosiglitazone may be crucial in its ability to protect against the neuronal damage caused by PTZ induced seizure.

Tauroursodeoxycholic Acid (TUDCA) Regulates Inflammation and Hypoxia in Autonomic Tissues of Rats with Seizures.

Inflammation and hypoxia have an effect on the molecular mechanism of cardiovascular and respiratory pathologies accompanying seizures. Against this, Tauroursodeoxycholic Acid (TUDCA) can regulate oxidative stress, inflammation and cellular survival by suppressing endoplasmic reticulum (ER) stress. We evaluated the expression changes of NF-κB p65, TNF-α, HIF1α and Kir6.2 proteins associated with seizures in brain stem, heart and lung tissues representing the autonomous network. Additionally, we examined the protective effects of TUDCA administration against damage caused by seizures in terms of immunohistochemistry and pathology. 4 groups of Wistar Albino male rats (250-300 g, n=32) were formed as control, pentylenetetrazole (PTZ), TUDCA and PTZ+TUDCA. The epilepsy kindling model was created by intraperitoneal (i.p.) injection of PTZ chemical (35 mg/kg, every 2 days) for one month. TUDCA (500 mg/kg; every 2 days) treatment was given intraperitoneally 30 minutes before seizures for 1 month. Brain stem, heart (atria, ventricle) and lung tissues of rats were isolated. NF-κB p65, TNF-α, HIF1α and Kir6.2 proteins in the obtained tissues were evaluated by immunohistochemical staining. The immunoreactivity of the investigated proteins in the brainstem heart and lung tissues of rats with chronic PTZ administration was significantly increased. Recurrent seizures led to accumulation of inflammatory cells in tissues, hemorrhage, vasodilation, and apoptosis. Following TUDCA administration, expression of NF-κB p65, TNF-α and Kir6.2 was significantly reduced in all tissues (except the atrium of the heart) compared to control rats. HIF-1α levels were significantly suppressed in ventricular and lung tissues of epileptic rats given TUDCA. However, TUDCA pretreatment improved histopathological changes due to chronic seizures and partially reduced apoptosis. We showed that epileptic seizures may cause tissue damage with the development of inflammatory and hypoxic conditions in the brainstem and organs that represent the autonomic network. TUDCA therapy could be an effective agent in the treatment of cardiac and respiratory problems associated with seizures.

Nicorandil Exerts Anticonvulsant Effects in Pentylenetetrazol-Induced Seizures and Maximal-Electroshock-Induced Seizures by Downregulating Excitability in Hippocampal Pyramidal Neurons.

N-(2-hydroxyethyl) nicotinamide nitrate (nicorandil), a nitrate that activates adenosine triphosphate (ATP)-sensitive potassium (KATP) channels, is generally used in the treatment of angina and offers long-term cardioprotective effects. It has been reported that several KATP channel openers can effectively alleviate the symptoms of seizure. The purpose of this study was to investigate the improvement in seizures induced by nicorandil. In this study, seizure tests were used to evaluate the effect of different doses of nicorandil by analysing seizure incidence, including minimal clonic seizure and generalised tonic-clonic seizure. We used a maximal electroshock seizure (MES) model, a metrazol maximal seizure (MMS) model and a chronic pentylenetetrazol (PTZ)-induced seizure model to evaluate the effect of nicorandil in improving seizures. Each mouse in the MES model was given an electric shock, while those in the nicorandil group received 0.5, 1, 2, 3 and 6mg/kg of nicorandil by intraperitoneal injection, respectively. In the MMS model, the mice in the PTZ group and the nicorandil group were injected subcutaneously with PTZ (90mg/kg), and the mice in the nicorandil group were injected intraperitoneally with 1, 3 and 5mg/kg nicorandil, respectively. In the chronic PTZ-induced seizure model, the mice in the PTZ group and the nicorandil group were injected intraperitoneally with PTZ (40mg/kg), and the mice in the nicorandil group were each given 1 and 3mg/kg of PTZ at a volume of 200nL. Brain slices containing the hippocampus were prepared, and cell-attached recording was used to record the spontaneous firing of pyramidal neurons in the hippocampal CA1 region. Nicorandil (i.p.) significantly increased both the maximum electroconvulsive protection rate in the MES model and the seizure latency in the MMS model. Nicorandil infused directly onto the hippocampal CA1 region via an implanted cannula relieved symptoms in chronic PTZ-induced seizures. The excitability of pyramidal neurons in the hippocampal CA1 region of the mice was significantly increased after both the acute and chronic administration of PTZ. To a certain extent, nicorandil reversed the increase in both firing frequency and proportion of burst spikes caused by PTZ (P < 0.05). Our results suggest that nicorandil functions by downregulating the excitability of pyramidal neurons in the hippocampal CA1 region of mice and is a potential candidate for the treatment of seizures.

The increase in c-fos expression in epileptic seizures is inhibited by magnetic field application, but not KCa1.1 channel expression

ABSTRACT The aim of this study was to understand the expression of big potassium (BK, KCa1.1) channels in epileptic seizures under magnetic field application. Forty Wistar albino adult male rats were divided into five groups (n = 8). First group rats were control group. Pentylenetetrazole (PTZ) administrated to second group rats to induce the seizures with 35 mg/kg intraperitoneally injection every two days. Levetiracetam (LEV) i.p. at a dose of 108 mg/kg was given to third group rats as positive control group (PC) before 20 minutes PTZ administration. Pulsed magnetic field with 1.5 mT was exposed to the fourth group rats for 3 hours a day for 1 month as magnetic field (MF) group. 1.5 mT pulsed magnetic field was exposed to the fifth group rats for 3 hours a day for 1 month in addition to PTZ administration (PTZ+MF). KCa1.1 not changed in hippocampus of PTZ rats while increased in frontal cortex and pons for PTZ group but not changed with magnetic field exposure. KCa1.1 increased in heart of PTZ animals and turned back to mean control values with magnetic field exposure. Suppressing the expected increase of c-fos protein expression in seizures with magnetic field application but not being able to change the KCa1.1 expression shows that new studies can be done by increasing the frequency of 1.5 mT magnetic field.

Possible Role of Oxidative Stress and Nrf2/HO-1 Pathway in Pentylenetetrazole-induced Epilepsy in Aged Rats.

To examine the impact of aging on the response of rats to pentylenetetrazole (PTZ)-induction of epilepsy and the possible role of oxidative stress and nuclear factor erythroid 2-related factor 2 (Nrf2)/ heme oxygenase (HO)-1 pathway in this response. Forty male albino rats were equally allocated into 4 groups; 1) Young control (YC) group, aged 8-12 weeks, 2) Old control (OC) group, aged 24 months, 3) PTZ-Young group: young rats received PTZ (50 mg/Kg, i.p. every other day) for 2 weeks and 4) PTZ-Old group: as group 3 but rats were old. The seizure score stage and latency to the first jerk were recorded in rats. Redox state markers in brain tissues including malondialdehyde (MDA), catalase and total antioxidant capacity (TAC) were evaluated. Also, the expression of Nrf2 and HO-1 genes were measured in the brain tissues. Old rats showed an early and a significant rise in the seizure score with PTZ administration and a significant drop in the seizure latency compared to young rats (P <0.01). Also, old rats showed a significantly higher MDA concentration and a significantly lower TAC and catalase activity than young rats (P <0.01). Moreover, the expression of Nrf2 and HO-1 was significantly lowered in old rats compared to young rats with PTZ administration (P < 0.01). Aging increases the vulnerability of rats to PTZ-induced epilepsy. An effect might come down to the up-regulation of oxidative stress and the down regulation of antioxidant pathways including Nrf2 and HO-1.

Effect of Deep Brain Stimulation in The Ventral Tegmental Area on Neuronal Activity in Local and Remote Brain Regions in Kindled Mice.

The mechanisms behind seizure suppression by deep brain stimulation (DBS) are not fully revealed, and the most optimal stimulus regimens and anatomical targets are yet to be determined. We investigated the modulatory effect of low-frequency DBS (L-DBS) in the ventral tegmental area (VTA) on neuronal activity in downstream and upstream brain areas in chemically kindled mice by assessing c-Fos immunoreactivity. In this experimental study, 4-6 weeks old BL/6 male mice underwent stereotaxic implantation of a unilateral stimulating electrode in the VTA followed by pentylenetetrazole (PTZ) administration every other day until they showed stage 4 or 5 seizures following 3 consecutive PTZ injections. Animals were divided into control, sham-implanted, kindled, kindled-implanted, L-DBS, and kindled+L-DBS groups. In the L-DBS and kindled+L-DBS groups, four trains of L-DBS were delivered 5 min after the last PTZ injection. 48 hours after the last L-DBS, mice were transcardially perfused, and the brain was processed to evaluate c-Fos expression by immunohistochemistry. L-DBS in the VTA significantly decreased the c-Fos expressing cell numbers in several brain areas including the hippocampus, entorhinal cortex, VTA, substantia nigra pars compacta, and dorsal raphe nucleus but not in the amygdala and CA3 area of the ventral hippocampus compared to the sham group. These data suggest that the possible anticonvulsant mechanism of DBS in VTA can be through restoring the seizure-induced cellular hyperactivity to normal.

Assessment of Anti-seizure Property of Plumbago indica L. on Zebrafish Model

The purpose of the current experiment was to determine the anti-convulsant activity of methanolic extract of Plumbago indica L. In a 50 ml beaker 200 mg of the methanolic extract of Plumbago indica L. was dissolved in water containing the experimental zebrafish. After about 20 minutes the fish was administered with pentylenetetrazole (PTZ) (30 mg in 0.5 ml water) intraperitoneally (i.p) to induce seizure in it. The experimental zebrafish immersed in methanolic extract of Plumbago indica L. and administered with PTZ i.p showed clonic seizure-like activity within a few seconds of administering the PTZ. After about 15 minutes, the experimental zebrafish was found to swim normally i.e., short swim at the top of the tank with no seizure activity. The behavioral profile during 15 minutes of immersion into methanolic extract of Plumbago indica L. and then intraperitoneum (i.p) administration of PTZ was characterized by stages defined as scores: (0) short swim (top of the tank), (1) increased swimming activity, (2) burst swimming (left and right movements), (3) circular movements, (4) clonic seizure-like behavior, (5) fall to the bottom of the tank and tonic seizure-like behavior, (6) death. To attain all scores, zebrafish was exposed to anti-convulsants and administered with PTZ showed varying seizure profiles, severity, and latencies. The study's findings revealed that Plumbago indica L. has significant pharmacological properties. Methanolic extract of Plumbago indica L. has a notable CNS depressive and anti-convulsant effect.

Xanthohumol Alleviates Epileptic Seizures in Pentylenetetrazol-Induced Convulsions in Mice by Regulating Inflammation and Oxidative Stress

Background: Epilepsy is a prevalent neurobehavioral disorder, which affects more the 50 million individuals worldwide. It is characterized by neuron hyperexcitability mediated by repetitive convulsions. The current investigation was planned to study the therapeutic properties of the xanthohumol against pentylenetetrazol (PTZ)-induced convulsions in mice by regulating inflammation and oxidative stress. Methods: The 70 mg/kg of PTZ was administered (i.p.) to the mice for stimulating the epileptic seizures and 20 mg/kg of xanthohumol was pre-treated by oral route before the 30 min of PTZ administration. The mice were observed closely for 30 min after the PTZ treatment to detect the onset and duration of clonic/tonic convulsions and mortality. The status of glutamate, GABA, dopamine, Na+K+ATPase, and Ca+ATPase were quantified using respective kits. The level of MDA, NO, GSH, and SOD were detected using standard methods. The levels of inflammatory biomarkers such as COX-2, TNF-α, NF-κB, TLR-4, and IL-1β in the brain tissues were inspected using kits. The histopathological analysis was done on the brain tissues. Results: The xanthohumol significantly (p &lt; 0.05) reduced the onset and duration of convulsions, mortality, and behavioral changes in the epileptic mice. The levels of COX-2, TNF-α, NF-κB, TLR-4, and IL-1β were significantly (p &lt; 0.05) decreased in the epileptic mice by 20 mg/kg xanthohumol treatment. The levels of MDA and NO was reduced and GSH and SOD were increased by the 20 mg/kg xanthohumol treatment. The 20 mg/kg xanthohumol significantly (p &lt; 0.05) decreased the glutamate and improved the dopamine, GABA, Na+K+ATPase, and Ca+ATPase in the epileptic mice. The findings of histopathological studies revealed that 20 mg/kg xanthohumol decreased the inflammatory signs and pyknosis in the brain tissues. Conclusion: Pre-treatment with the 20 mg/kg xanthohumol ameliorates the PTZ-triggered seizures in a mice model through its antioxidant and anti-inflammatory potentials. Hence, xanthohumol can be a promising antiepileptic candidate in the future to treat epilepsy.