Maximal Electroshock Seizure Research Articles

PRAX-628 is a Novel, Well-Tolerated, Activity Dependent Sodium Channel Blocker with Potent Anticonvulsant Activity (P4-9.012)

<h3>Objective:</h3> We sought to define the <i>in vivo</i> efficacy and tolerability profile of PRAX-628, a novel activity dependent sodium channel blocker. <h3>Background:</h3> Gain-of-function (GoF) pathogenic variants in voltage-gated sodium channel (Na_V) genes can increase persistent sodium current (I_Na) leading to neuronal hyperexcitability and severe developmental and epileptic encephalopathies (DEE). We show in Kahlig et al., (this meeting) that PRAX-628 inhibits I_Na with greater activity dependence compared to standard of care carbamazepine (CBZ) and lamotrigine (LTG). Here we further define its <i>in vivo</i> efficacy and tolerability profile in mice. <h3>Design/Methods:</h3> The anticonvulsant activity of PRAX-628 (0.3–10 mg/kg) was assessed using the maximal electroshock seizure (MES) assay in outbred CD-1 mice. Effects of PRAX-628 (3–20 mg/kg) on spontaneous locomotor activity (sLMA) were measured to assess tolerability. The protective index (PI) of PRAX-628 was determined as the ratio of plasma concentrations in sLMA (TC₅₀) to MES (EC₅₀). The effects of CBZ and LTG were also assessed using MES (3–30 mg/kg and 1–10 mg/kg, respectively) and sLMA (30–96 mg/kg and 20–63.4 mg/kg, respectively), and their corresponding PIs computed. The concentration of PRAX-628 in terminal plasma and brain samples was measured using mass spectrometry. <h3>Results:</h3> PRAX-628 (10 mg/kg) completely blocked evoked seizures (MES ED₅₀ 0.67 mg/kg, brain EC₅₀ 67.2 ng/g) without affecting sLMA (TD₅₀ 10.27 mg/kg, plasma TC₅₀ 1123 ng/g; PI 16.7). In contrast, CBZ and LTG had PIs of 5–6x; full anticonvulsant efficacy with CBZ or LTG was not achieved without reducing sLMA. <h3>Conclusions:</h3> PRAX-628 exhibited markedly improved preclinical tolerability compared to standard of care Na_V blockers, potentially due to its improved activity dependent inhibition of peak I_Na. The profile of PRAX-628 may translate into well-tolerated efficacy in epilepsy as well as other indications caused by neuronal hyperexcitability. <b>Disclosure:</b> Dr. Eckert has received personal compensation for serving as an employee of Praxis Precision Medicines. Dr. Eckert has received personal compensation for serving as an employee of Janssen Research &amp; Development, LLC. Dr. Eckert has received personal compensation for serving as an employee of Inspire Pharmaceuticals, Inc.. Dr. Eckert has stock in Praxis Precision Medicines. Dr. Eckert has stock in Janssen Research and Development. Dr. Eckert has received intellectual property interests from a discovery or technology relating to health care. Dr. Kahlig has received personal compensation for serving as an employee of Praxis Precisoin Medicines. Dr. Kahlig has stock in Praxis Precision Medicines. Dr. Anderson has received personal compensation for serving as an employee of Praxis Precision Medicines. Steven Petrou has received personal compensation in the range of $100,000-$499,999 for serving as a Consultant for Praxis Precision Medicines. Steven Petrou has stock in Praxis Precision Medicines. The institution of Steven Petrou has received research support from Praxis Precision Medicines. The institution of Steven Petrou has received research support from Medical Research Future Fund. Steven Petrou has received intellectual property interests from a discovery or technology relating to health care. Steven Petrou has received intellectual property interests from a discovery or technology relating to health care.

PRAX-562 is a Well-Tolerated, Novel Persistent Sodium Channel Blocker with Broad Anticonvulsant Activity in Multiple DEE Mouse Models (S34.007)

PRAX-562 is a Well-Tolerated, Novel Persistent Sodium Channel Blocker with Broad Anticonvulsant Activity in Multiple DEE Mouse Models (S34.007)

PRAX-562-102: A Phase 1 Trial Evaluating the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of PRAX-562 in Healthy Volunteers (P4-9.011)

<h3>Objective:</h3> We report findings from a Phase 1 clinical trial characterizing the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of PRAX-562 in healthy adults. <h3>Background:</h3> PRAX-562 is a next-generation sodium channel blocker with a unique profile expected to translate to a wider therapeutic window compared to current standard-of-care for severe DEE. <h3>Design/Methods:</h3> PRAX-562-102 was a randomized, placebo-controlled trial in healthy adults (18–55 years). Part A evaluated 90mg PRAX-562 over 28 days (QD) vs. placebo. Part B evaluated oxcarbazepine (OXC) in combination with 120mg PRAX-562 (QD) over 28 days vs. OXC alone. PD effects were examined on quantitative EEG (qEEG) and stimulated EEG (auditory steady state response, ASSR). <h3>Results:</h3> 48 participants were enrolled (Part A, n=18 PRAX-562, n=12 placebo; Part B, n=14 OXC+PRAX-562, n=4 OXC+placebo). PRAX-562 concentrations exceeded the EC₅₀ in the mouse maximal electroshock seizure (MES) model by 13-fold and was unaltered with OXC coadministration. PRAX-562 was generally well tolerated in Part A. TEAEs were mostly mild or moderate (100% Part A; 96% Part B). Part B was stopped early after 5 participants receiving OXC+PRAX-562 developed TEAEs; one of whom experienced 3 study drug-related SAEs leading to study drug discontinuation. Exposure-depended PD changes were observed on qEEG (all frequencies) and ASSR. Significant differences between placebo and PRAX-562 were observed in Part A on qEEG (Delta, <i>P</i>=0.0013; Theta, <i>P</i>&lt;0.0001) and ASSR (phase-locking-factor, <i>P</i>=0.028; Evoked power, <i>P</i>=0.016), and in Part B participants receiving OXC+PRAX-562 vs. OXC alone on qEEG (Delta, <i>P</i>=0.012; Theta, <i>P</i>=0.018). <h3>Conclusions:</h3> PRAX-562 was well tolerated in healthy adults at 90mg (Part A). Most AEs including SAEs in Part B were considered due to coadministration of projected supratherapeutic doses of PRAX-562 with OXC. Our PK and tolerability findings are consistent with a wide therapeutic window for PRAX-562, while PD findings indicate qEEG may be a sensitive translational biomarker of sodium channel blockade. <b>Disclosure:</b> Dr. Mahalingam has nothing to disclose. Dr. Oldham has received personal compensation for serving as an employee of Praxis Precision Medicines. Dr. Puryear has received personal compensation for serving as an employee of Praxis Precision Medicine. Dr. Puryear has stock in Praxis Precision Medicines. Dr. Bansal has received personal compensation for serving as an employee of Praxis precision medicines . Dr. Bansal has stock in Praxis Precision medicines . Dr. Sriram has received personal compensation for serving as an employee of Praxis Precision Medicines. Dr. Sriram has stock in Praxis Precision Medicines. Dr. Sriram has stock in Biogen Inc. Dr. Patel has received personal compensation for serving as an employee of Praxis Precision Medicines, Inc.. Dr. Patel has received personal compensation for serving as an employee of Noven Pharmaceuticals. Dr. Patel has stock in Praxis Precision Medicines, Inc.. Dr. Jacotin has received personal compensation for serving as an employee of Praxis Precision Medicines. Dr. Jacotin has received personal compensation for serving as an employee of Takeda. Dr. Jacotin has stock in Takeda. Dr. Jacotin has stock in Certara. Dr. Jacotin has stock in Clover Health. Dr. Jacotin has stock in Coinbase. Marjie Hard has nothing to disclose. Dr. Arefayene has nothing to disclose. Dr. Ravina has received personal compensation for serving as an employee of Praxis Precision Medicines. Dr. Ravina has stock in Praxis. Dr. Souza has received personal compensation for serving as an employee of Praxis Precision Medicines. Dr. Souza has stock in Praxis Precision Medicines. Steven Petrou has received personal compensation in the range of $100,000-$499,999 for serving as a Consultant for Praxis Precision Medicines. Steven Petrou has stock in Praxis Precision Medicines. The institution of Steven Petrou has received research support from Praxis Precision Medicines. The institution of Steven Petrou has received research support from Medical Research Future Fund. Steven Petrou has received intellectual property interests from a discovery or technology relating to health care. Steven Petrou has received intellectual property interests from a discovery or technology relating to health care.

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.

Antiseizure Properties of Histamine H3 Receptor Antagonists Belonging 3,4-Dihydroquinolin-2(1H)-Ones.

H3R is becoming an attractive and promising target for epilepsy treatment as well as the discovery of antiepileptics. In this work, a series of 6-aminoalkoxy-3,4-dihydroquinolin-2(1H)-ones was prepared to screen their H3R antagonistic activities and antiseizure effects. The majority of the target compounds displayed a potent H3R antagonistic activity. Among them, compounds 2a, 2c, 2h, and 4a showed submicromolar H3R antagonistic activity with an IC50 of 0.52, 0.47, 0.12, and 0.37 μM, respectively. The maximal electroshock seizure (MES) model screened out three compounds (2h, 4a, and 4b) with antiseizure activity. Meanwhile, the pentylenetetrazole (PTZ)-induced seizure test gave a result that no compound can resist the seizures induced by PTZ. Additionally, the anti-MES action of compound 4a fully vanished when it was administrated combined with an H3R agonist (RAMH). These results showed that the antiseizure role of compound 4a might be achieved by antagonizing the H3R receptor. The molecular docking of 2h, 4a, and PIT with the H3R protein predicted their possible binding patterns and gave a presentation that 2h, 4a, and PIT had a similar binding model with H3R.

(+)-Borneol enantiomer ameliorates epileptic seizure via decreasing the excitability of glutamatergic transmission.

Epilepsy is one common brain disorder, which is not well controlled by current pharmacotherapy. In this study we characterized the therapeutic potential of borneol, a plant-derived bicyclic monoterpene compound, in the treatment of epilepsy and elucidated the underlying mechanisms. The anti-seizure potency and properties of borneol were assessed in both acute and chronic mouse epilepsy models. Administration of (+)-borneol (10, 30, 100 mg/kg, i.p.) dose-dependently attenuated acute epileptic seizure in maximal-electroshock seizure (MES) and pentylenetetrazol (PTZ)-induced seizure models without obvious side-effect on motor function. Meanwhile, (+)-borneol administration retarded kindling-induced epileptogenesis and relieved fully kindled seizures. Importantly, (+)-borneol administration also showed therapeutic potential in kainic acid-induced chronic spontaneous seizure model, which was considered as a drug-resistant model. We compared the anti-seizure efficacy of 3 borneol enantiomers in the acute seizure models, and found (+)-borneol being the most satisfying one with long-term anti-seizure effect. In electrophysiological study conducted in mouse brain slices containing the subiculum region, we revealed that borneol enantiomers displayed different anti-seizure mechanisms, (+)-borneol (10 μM) markedly suppressed the high frequency burst firing of subicular neurons and decreased glutamatergic synaptic transmission. In vivo calcium fiber photometry analysis further verified that administration of (+)-borneol (100 mg/kg) inhibited the enhanced glutamatergic synaptic transmission in epilepsy mice. We conclude that (+)-borneol displays broad-spectrum anti-seizure potential in different experimental models via decreasing the glutamatergic synaptic transmission without obvious side-effect, suggesting (+)-borneol as a promising anti-seizure compound for pharmacotherapy in epilepsy.

Evaluation of the Effect of Pheophytin A on Electroshock- Induced Seizures in Experimental Animals

Abstract: Background: An epileptic seizure is a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Approximately, 5–10% of the people have at least one kind of seizure, with more chance of occurrence in early childhood and late adulthood. There are many drugs used in seizures such as phenytoin and valproate sodium, so the main objective of current study was evaluated the efficacy of Pheophytin A compared to Valproate sodium on electroshock-induced seizures in experimental mice. Materials and Methods: The total number of 18 mice were used after divided into 3 groups in which each group was 6 mice. The first group, which is control, was received injection with distilled water. The second group was standard reference which received valproate sodium at dose of 300 mg/kg. The third group was test group which received 20 mg /kg of pheophytin A. Maximum electrical shocker was used to induce seizures. Results: The present study showed that pheophytin-A group had significantly reduced duration of seizures after 30 min of injection as compared to valproate sodium group. Valproate sodium produced more reduction in duration of seizures than pheophytin-A. Conclusion: The Pheophytin A showed antiseizure effect using maximal electrical shocker, so that it may be used in the future for treatment of seizures after further investigations. Keywords: Seizures, Pheophytin A, Valproate sodium, Maximal electroshock seizure, In vivo.

Alterations in the properties of the glutamatergic system of the rat hippocampus in a lithium-pilocarpine model of temporal lobe epilepsy

Status epilepticus (SE) triggers many pathological changes in the nervous system that are not yet fully understood and may lead to the development of epilepsy. In this work, we studied the effects of SE on the properties of excitatory glutamatergic transmission in the hippocampus in a rat model of lithium-pilocarpine temporal lobe epilepsy. Studies were performed 1 day (acute phase of the model), 3 and 7 days (latent phase), and 30 to 80 days (chronic phase) after SE. Using real-time PCR, we found that in the latent phase there is a decrease in gene expression of GluA1 and GluA2 AMPA receptor subunits, which may also be accompanied by an increased proportion of calcium-permeable AMPA receptors, which play an essential role in the pathogenesis of many CNS diseases. In acute brain slices we found a decrease in the efficiency of excitatory synaptic neurotransmission in all phases of the model when recording field responses in the CA1 region of the hippocampus in response to stimulation of Schaffer collaterals by electric currents of different intensities. However, in the chronic phase we found an increase in the frequency of spontaneous excitatory postsynaptic potentials, indicating an increased background activity of the glutamatergic system in epilepsy. This is also supported by a decrease in the threshold of hind limb extension in the test of maximal electroshock seizure in rats with temporal lobe epilepsy compared to control animals. The results obtained indicate the presence of a number of functional alterations in the glutamatergic system related to epilepsy. These findings can be used to develop antiepileptogenic therapy.

Alterations in the Properties of the Rat Hippocampus Glutamatergic System in the Lithium-Pilocarpine Model of Temporal Lobe Epilepsy

Status epilepticus (SE) triggers many not yet fully understood pathological changes in the nervous system that can lead to the development of epilepsy. In this work, we studied the effects of SE on the properties of excitatory glutamatergic transmission in the hippocampus in the lithium-pilocarpine model of temporal lobe epilepsy in rats. The studies were performed 1 day (acute phase), 3 and 7 days (latent phase), and 30 to 80 days (chronic phase) after SE. According to RT-qPCR data, expression of the genes coding for the AMPA receptor subunits GluA1 and GluA2 was downregulated in the latent phase, which may lead to the increased proportion of calcium-permeable AMPA receptors that play an essential role in the pathogenesis of many CNS diseases. The efficiency of excitatory synaptic neurotransmission in acute brain slices was decreased in all phases of the model, as determined by recording field responses in the CA1 region of the hippocampus in response to the stimulation of Schaffer collaterals by electric current of different strengths. However, the frequency of spontaneous excitatory postsynaptic potentials increased in the chronic phase, indicating an increased background activity of the glutamatergic system in epilepsy. This was also evidenced by a decrease in the threshold current causing hindlimb extension in the maximal electroshock seizure threshold test in rats with temporal lobe epilepsy compared to the control animals. The results suggest a series of functional changes in the properties of glutamatergic system associated with the epilepsy development and can be used to develop the antiepileptogenic therapy.

Design, Synthesis, and Pharmacology of New Triazole-Containing Quinolinones as CNS Active Agents.

Epilepsy and major depressive disorder are the two of the most common central nervous system (CNS) diseases. Clinicians and patients call for new antidepressants, antiseizure medicines, and in particular drugs for depression and epilepsy comorbidities. In this work, a dozen new triazole-quinolinones were designed, synthesized, and investigated as CNS active agents. All compounds reduced the immobility time significantly during the forced swim test (FST) in mice at the dosage of 50 mg/kg. Compounds 3f-3j gave superior performance over fluoxetine in the FST with more reductions of the immobility time. Compound 3g also reduced immobility time significantly in a tail suspension test (TST) at the dosage of 50 mg/kg, though its anti-immobility activity was inferior to that of fluoxetine. An open field test was carried out and it eliminated the false-positive possibility of 3g in the FST and TST, which complementarily supported the antidepressant activity of 3g. We also found that almost all compounds except 3k exhibited antiseizure activity in the maximal electroshock seizure (MES) model at 100 or 300 mg/kg. Compounds 3c, 3f, and 3g displayed the ED50 of 63.4, 78.9, and 84.9 mg/kg, and TD50 of 264.1, 253.5, and 439.9 mg/kg, respectively. ELISA assays proved that the mechanism for the antiseizure and antidepressant activities of compound 3g was via affecting the concentration of GABA in mice brain. The molecular docking study showed a good interaction between 3g and the amino acid residue of the GABAA receptor. Excellent drug-like properties and pharmacokinetic properties of compound 3a-l were also predicted by Discovery Studio. These findings provided a new skeleton to develop agents for the treatment of epilepsy and depression comorbidities.

The effects of cannabidiol and Δ9-tetrahydrocannabinol, alone and in combination, in the maximal electroshock seizure model

In the present study, cannabidiol (CBD), Δ9-tetrahydrocannabinol (THC), and combinations of CBD and THC, were evaluated in the mouse maximal electroshock (MES) seizure test – an animal model of generalized-onset seizures. Male CF-1 mice were injected intraperitoneally (i.p.) with either CBD, THC or a combination of CBD and THC. The MES test was conducted 2 h after the injection of CBD and 1 h after the injection of THC. A wide range of doses was tested to allow the construction of dose-response curves. Toxicity was assessed using a behavioral rating scale. It was found that: 1) the ED50 for THC alone was 52 mg/kg and its therapeutic index (TI) was 1.7; 2) the ED50 for CBD alone was 190 mg/kg and its TI was 2.4; and 3) the ED50 for a 15:1 combination of CBD+THC was 130 mg/kg + 8.6 mg/kg (CBD + THC). Thus, CBD and THC were both effective in the MES model, and CBD was somewhat more effective in the presence of low (non-therapeutic) doses of THC. The improvement in CBD’s effect, however, was less dramatic than that seen in past experiments with the amygdala-kindling model (Fallah et al., 2021). Both CBD alone and CBD+THC in combination might be useful in the treatment of generalized-onset seizures. The advantage of adding THC to CBD, however, might be less than in the treatment of focal-onset seizures.

Dietary Zinc Differentially Regulates the Effects of the GPR39 Receptor Agonist, TC-G 1008, in the Maximal Electroshock Seizure Test and Pentylenetetrazole-Kindling Model of Epilepsy.

The G-protein coupled receptor 39 (GPR39) is gaining increasing attention as a target for future drugs, yet there are gaps in the understanding of its pharmacology. Zinc is an endogenous agonist or an allosteric modulator, while TC-G 1008 is a synthetic, small molecule agonist. Zinc is also a positive allosteric modulator for the activity of TC-G 1008 at GPR39. Activation of GPR39 by TC-G 1008 facilitated the development of epileptogenesis in the pentylenetetrazole (PTZ)-induced kindling model of epilepsy. Congruently, TC-G 1008 decreased the seizure threshold in the maximal electroshock seizure threshold (MEST) test. Here, we investigated the effects of TC-G 1008 under the condition of zinc deficiency. Mice were fed a zinc-adequate diet (ZnA, 50 mg Zn/kg) or a zinc-deficient diet (ZnD, 3 mg Zn/kg) for 4 weeks. Following 4 weeks of dietary zinc restriction, TC-G 1008 was administered as a single dose and the MEST test was performed. Additional groups of mice began the PTZ-kindling model during which TC-G 1008 was administered repeatedly and the diet was continued. TC-G 1008 administered acutely decreased the seizure threshold in the MEST test in mice fed the ZnD diet but not in mice fed the ZnA diet. TC-G 1008 administered chronically increased the maximal seizure severity and the percentage of fully kindled mice in those fed the ZnA diet, but not in mice fed the ZnD diet. Our data showed that the amount of zinc in a diet is a factor contributing to the effects of TC-G 1008 in vivo.

Anticonvulsant property of celecoxib in maximal electroshock seizure: Correlating the role of inflammation in pathophysiology of epileptic seizures

Background: Epilepsy is an abnormal excessive electric neuronal activity and always represents by recurrent seizures. There is positive feedback cycle between epileptogenesis and brain inflammation. It has been proved that an inflammatory enzyme, cyclooxygenase (COX) (especially isoform-2, a constitutive enzyme), expressed in some important parts of the central nervous system and is responsible to induced inflammation locally and having seizurogenic property. Aim and Objective: The goal of this study was to see if celecoxib (a selective COX-2 inhibitor) could reduce the maximal electroshock seizure (MES)-induced seizures in mice. Materials and Methods: Celecoxib injected intraperitoneally in two different doses 5 mg/kgb/w and 10 mg/kg b/w, in albino Swiss mice and in two different phases. MES was elicited and length of different phases was noted. Length of tonic hindlimb extension was considered as indicator of anti-epileptic activity. Results: Celecoxib, when given intraperitoneally, exert significant reduction in the duration of THLE. This action of celecoxib strongly suggests the involvement of inflammation in the pathophysiology of epilepsy. Conclusion: The findings are suggestive of the therapeutic significance of celecoxib, as a future antiepileptic agent for seizure management.

Evaluation of Anticonvulsant Action of Nebivolol in Albino Mice

Background: Epilepsy is a disorder of brain function indicating periodic and unpredictable occurrence of seizures. Hypertension is the main cause of intracerebral hemorrhage which is a triggering factor for development of epilepsy. Nebivolol, a β-blocker is an anti-hypertensive drug, could decrease the glutaminergic transmission with addition of antioxidant property as a contributing factor may possibly provide anticonvulsant effect. Aim and Objective: The aim of the study was to study the anticonvulsant effect of Nebivolol in Albino mice. Materials and Methods: An either sex of Albino mice weighing between 18 and 22 g were used. Forty-eight animals (n = 48) were divided into eight groups with six in each group; four groups each for maximal electroshock (MES) and pentylenetetrazole (PTZ) models, respectively. Hind Limb Flexion, Hind Limb Extension, Clonus, and Postictal Depression were observed using MES model, Seizure latency and Duration of seizures were observed using PTZ model. Results: Nebivolol showed anticonvulsant effect with MES convulsions at both 0.25 mg/kg and 0.5 mg/kg but this effect is not equivalent to that of phenytoin in the present study. In terms of duration of tonic hind limb flexion and post-ictal depression, Nebivolol 0.5 mg/kg dose has comparable results to that of phenytoin. In PTZ model, Nebivolol decreased the seizure duration but did not delay the seizure onset, which were comparable to the standard Diazepam. Conclusion: Nebivolol may possibly be beneficial in treating generalized tonic clonic seizures and absence seizures. However, more extended studies are needed to prove the anticonvulsant effect of Nebivolol and enable its use in clinical practice.

Microwave Assisted Synthesis and Evaluation of Anticonvulsant Activity of Some 3-(3-(Substituted benzylidine)amino)phenyl-2-phenylquinazolin-4(3H)-ones

Herein, the synthesis of 3-(3-(substituted benzylidine)amino)phenyl-2-phenylquinazolin-4(3H)-ones from 3-aminophenyl-2-phenyl-quinazolin-4(3H)-ones is reported. The chemical structures of the synthesized compounds were confirmed by FT-IR, 1H NMR and 13C NMR studies. All compounds were evaluated for their anticonvulsant activity against maximal electroshock seizure method. The LD50 value was found to be 550 mg/Kg and the duration of tonic phase was reduced upto 1.1 s and that of stupor phase was reduced upto 70 s. The structure activity relationship of the compounds revealed that Schiff bases viz. 3-(3-benzylidineamino)phenyl-2-phenylquinazolin-4(3H)-one, 3-(3-(3- chlorobenzylidine)amino)phenyl-2-phenylquinazolin-4(3H)-one, 3-(3-(3- nitrobenzylidine)amino)phenyl-2-phenylquinazolin-4(3H)-one by significantly shorten the tonic and stupor phases of convulsions compared to controls, thus thereby these compounds demonstrated strong anticonvulsant potential.

In vitro and in vivo anti-seizure activity of hydromethanolic extract and fractions of Pterolobium stellatum

Ethnopharmacological relevanceIn Ethiopia, the whole plant juice of Pterolobium stellatum is used to treat seizures and epilepsy. Aim of the studyTo investigate the antiseizure activity of hydromethanolic crude extract and fractions collected from leaves of P. stellatum using both in vitro, and in vivo seizure models in mice. Materials and methodsFresh leaves of P. stellatum were collected from Awash Melka, Addis Ababa, Ethiopia. An 80% crude methanol extract was further fractionated to produce petroleum ether, chloroform, butanol, and aqueous fractions. Anti-seizure activity of the crude extract and fractions (petroleum ether, chloroform, butanol, and water) were assessed at a concentration of 0.7 mg/ml using the in vitro 0 Mg2+ model of seizures in mouse brain slices prepared from 14- to 21-day-old C57BL/6 mice. The maximal electroshock seizure (MES) model and the pentylenetetrazol (PTZ) seizure model for seizures were performed on male BALB/c mice using 400 mg/kg and 800 mg/kg of crude 80% methanol extract, as well as the four fractions described above. Diazepam and phenytoin were used as positive controls for PTZ and MES test respectively. ResultsAddition of 0.7 mg/ml of crude 80% methanol extract of P. stellatum prevented the onset of SLEs in most brain slices in the 0 Mg2+in vitro model of seizures, with similar efficacy to diazepam (3 μM). The same extract at 400 and 800 mg/kg was efficacious in reducing the hindlimb extension time in the MES model and delaying the onset of myoclonic convulsions in the PTZ model, although not to the same extent as phenytoin (10 mg/kg) or diazepam (5 mg/kg). The chloroform and water fractions of the crude extract also showed significant anti-seizure activity across all three models whilst the non-polar petroleum ether and butanol fractions did not. The UPLC-MS analysis indicated the presence of gallic acid, ellagic acid, kaempferol, myricitrin, isoquercitrin and quercitirin in the crude extract. Gallic acid and ellagic acid were observed in chloroform fraction and in the water fraction ellagic acid, kaempferol, myricitrin and isoquercitrin were detected. ConclusionThe crude hydromethanolic extract of P. stellatum has significant anti-seizure activity. The chloroform and aqueous fractions have antiseizure activity. The extracts have previously identified compounds with anticonvulsant activity which indicates the antiseizure potential of the plant.

Pharmacodynamic synergism contributes to the antiseizure action of cannabidiol and clobazam

The management of refractory epilepsy involves treatment with more than one antiseizure medication (ASM). Combination of ASMs with distinct mechanisms of action are hypothesized to improve overall treatment effectiveness. In clinical trials, concomitant use of cannabidiol (CBD) and clobazam (CLB) was associated with increased seizure reduction and bidirectional elevation in levels of their active metabolites, 7-hydroxy-cannabidiol (7-OH-CBD) and nor-clobazam (n-CLB). Using isobolographic analysis, we investigated whether CBD and CLB interacted pharmacodynamically. In the mouse maximal electroshock seizure (MES) test, brain tissue levels of CBD and CLB corresponding to seizure prevention in 50% of animals (brain Effective Exposure, bEE50) were 7.9 μM and 1.6 μM, respectively. In the 6 Hz psychomotor seizure model, 7-OH-CBD displayed a 5-fold greater potency than CBD (b-EE50, 8.7 μM vs 47.3 μM). Isobolographic analysis performed on combination of CBD/CLB at 1:1, 3:1, and 1:3 ratios based on equi-effective bEE50 values revealed synergism at all doses with combination indices (CI) of 0.43, 0.62 and 0.75 respectively. These outcomes were independent of pharmacokinetic interaction between CBD and CLB. These findings identify pharmacodynamic synergism as an important factor underlying enhanced antiseizure effect during concomitant CBD and CLB use.

Caffeine impairs anticonvulsant effects of levetiracetam in the maximal electroshock seizure threshold test in mice.

Caffeine is the most widely used psychoactive substance in the world. Animal studies indicate that acute caffeine exposure at high doses may induce seizures anddiminish the anticonvulsant activity of antiepileptic drugs (AEDs) at much lower doses. The aim of the current study was to assess the effect of caffeine on the anticonvulsant action of levetiracetam (LEV) and vigabatrin (VGB). The anticonvulsant activity of LEV and VGB was examined in the maximal electroshock seizure threshold test in mice (MEST test). All drugs were administered intraperitoneally by single injections, and caffeine was applied at doses capable of interfering with AEDs. Effects of caffeine exposure on AEDs were also investigated in tests of memory and motor performance. Caffeine reduced the protective effect of LEV against electroconvulsions. Total brain concentration of LEV was unaffected by caffeine as well as inversely; LEVhad no significant impact on the brain caffeine concentration, suggesting a pharmacodynamic nature of theinteraction between LEV and caffeine in the MEST test.VGB at applied doses did not affect the convulsive threshold. Administration of VGB, but not LEV, alone orincombination with caffeine, impaired memory retention. In the chimney test, the combined treatment with AEDs and caffeine did not cause motor coordination impairment. It is suggested that caffeine may negatively affect the anticonvulsant action of LEV in patients with epilepsy.

Glyceryl triacetate feeding in mice increases plasma acetate levels but has no anticonvulsant effects in acute electrical seizure models

IntroductionAcetate has been shown to have neuroprotective and anti-inflammatory effects. It is oxidized by astrocytes and can thus provide auxiliary energy to the brain in addition to glucose. Therefore, we hypothesized that it may protect against seizures, which is investigated here by feeding glyceryl triacetate (GTA), to provide high amounts of acetate without raising sodium or acid levels. MethodCD1 male mice were fed controlled diets with or without GTA for up to three weeks. Body weights, blood glucose levels, plasma short-chain fatty acid levels, and other hematological parameters were monitored. Seizure thresholds were determined in 6 Hz and maximal electroshock seizure threshold (MEST) tests. Antioxidant capacities were evaluated in the cerebral cortex and plasma using a ferric reducing antioxidant power (FRAP) assay and Trolox equivalent antioxidant capacity assay. ResultsBody weight gain was similar with both diets with and without GTA in two experiments. Glyceryl triacetate-fed groups showed 2–3- and 1.6-fold increased acetate and propionate levels in plasma, respectively. Glucose levels were unaltered in blood collected from the tail tip but increased in trunk blood. No differences were found in the activity of cerebral cortex acetyl-CoA synthetase. In the 6 Hz threshold test, seizure thresholds were lower by 3 mA and 2.4 mA after 8 and 14 days, respectively, in the GTA compared to the control diet-fed group, but showed no difference on day 16, showing that GTA has small, but inconsistent proconvulsant effects in this model. In MEST tests, a slightly increased seizure threshold (1 mA) was found on day 19 in the GTA-fed group, but not in another experiment on day 21. There were no differences in antioxidant capacity in plasma or cortex between the two groups. ConclusionGlyceryl triacetate feeding showed no antioxidant effects nor beneficial changes in acute electrical seizure threshold mouse models, despite its ability to increase plasma acetate levels.

Insulin potentiates the anticonvulsive activity of phenytoin against maximal electroshock-induced seizures in mice.

The limitations imposed by the blood-brain barrier (BBB) on the sufficient accumulation of antiepileptic drugs (AEDs) in the epileptogenic focus is considered the major cause of the high percentage of morbidity and mortality cases among epilepsy patients. This study aimed at examining the potential effect of insulin on the anticonvulsant action of phenytoin (PHT) in the mouse maximal electroshock-induced seizure model. PHT was administered orally in single doses either alone or in combination with insulin given as single intraperitoneal injections. To assess the anticonvulsant activity of PHT, the ED50 values were calculated. The current strength (CS50) threshold for insulin was also estimated. The animals were sacrificed, and the brains were removed to measure their PHT concentrations in the brain. It has been demonstrated that insulin (in all used doses) has no effect on the CS50 but can cause a significant increase in concentrations of PHT in the brain and potentiate the antiepileptic efficiency of this drug in electroshock-induced models of epilepsy in mice. The combination of insulin with PHT may be of great importance for developing new treatment possibilities following further investigations with otheranimal models of epilepsyandpreclinical studies. Further research is also needed to explore the concentrations of PHT in the brain and the anticonvulsant activity of this drug against maximal electroshock seizures in diabetic mice.