External validation of newly modified status epilepticus severity score for predicting mortality in patients with status epilepticus in a regional hospital in Taiwan.

PURPOSE: To evaluate and compare the performance of the status epilepticus severity score (STESS), modified STESS (mSTESS), and the newly modified STESS (nSTESS) in predicting mortality in patients with status epilepticus (SE) at a regional hospital in Taiwan. METHODS: Data were collected from 81 patients with SE, aged over 18 years at a regional medical hospital in Tainan from January 2012 to December 2022. SE were treated following the standard treatment protocol. Exclusion criteria included missing data, lack of adherence to the treatment protocol, and transfer to tertiary medical centers. Outcome measures included differences in characteristics between survivor and non-survivor groups, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of STESS, nSTESS, mSTESS. Receiver operating characteristic (ROC) curve and area under curve (AUC) of scales were generated. Calibration with Hosmer-Lemeshow test was built as well. RESULTS: The study found significant differences in seizure types (p = 0.015) and undergoing intubation (p = 0.017) between survivor and non-survivor groups. No significant differences were observed in age, gender, underlying diseases, or the category of antiseizure medications (ASMs) usage. The ROC curve for STESS, nSTESS and mSTESS showed similar predictive values of around 0.75, indicating moderate performance of prediction. The Hosmer-Lemeshow test showed no significant difference between real-world predictions and these three clinical scales. In the aspect of accuracy, sensitivity and specificity, nSTESS has similar overall accuracy as in STESS and mSTESS. CONCLUSION: This external validation study demonstrates the moderate performance of nSTESS in predicting mortality in SE patients at a regional hospital in Taiwan. These outcomes underscore the practical utility of these scales in clinical practice, with nSTESS demonstrating accuracy on par with the others. Further validation in larger, multicenter cohorts and other healthcare settings is necessary to fully confirm its predictive value.

Identification of New Antiseizure Medication Candidates in Preclinical Animal Studies.

Epilepsy is a multifactorial neurologic disease that often leads to many devastating disabilities and an enormous burden on the healthcare system. Until now, drug-resistant epilepsy has presented a major challenge for approximately 30% of the epileptic population. The present article summarizes the validated rodent models of seizures employed in pharmacological researches and comprehensively reviews updated advances of novel antiseizure candidates in the preclinical phase. Newly discovered compounds that demonstrate antiseizure efficacy in preclinical trials will be discussed in the review. It is inspiring that several candidates exert promising antiseizure activities in drug-resistant seizure models. The representative compounds consist of derivatives of hybrid compounds that integrate multiple approved antiseizure medications, novel positive allosteric modulators targeting subtype-selective γ-Aminobutyric acid type A receptors, and a derivative of cinnamamide. Although the precise molecular mechanism, pharmacokinetic properties, and safety are not yet fully clear in every novel antiseizure candidate, the adapted approaches to design novel antiseizure medications provide new insights to overcome drug-resistant epilepsy.

Detailed risks and characteristics of postepilepsy stroke in non-traumatic adult-onset epilepsy.

BACKGROUND: Patients with epilepsy have an increased risk of stroke. However, the detailed risk and characteristics of postepilepsy stroke have not been investigated. METHODS: This study utilized the National Health Insurance Research Database in Taiwan. We classified adult patients with newly diagnosed epilepsy from 2003 to 2016 as the epilepsy cohort. Patients in the nonepilepsy cohort were selected with propensity score matching at a case-control ratio of 1:5. The incidence, hazard ratio (HR), period-specific HR, recurrent HR in the Wei-Lin-Weissfeld model, stroke severity index, complications, and mortality of all stroke, ischemic stroke (IS) and hemorrhagic stroke events in the two cohorts were analyzed. RESULTS: We enrolled 23,810 patients in the epilepsy cohort and 119,050 persons in the nonepilepsy cohort. The period-specific HRs of all stroke, IS and hemorrhagic stroke peaked immediately after epilepsy diagnosis and trended downward [Adjusted HRs of all stroke: 4.88 (3.88-6.14), 4.47 (3.50-5.70), 3.17 (2.62-3.84), 2.81 (2.27-3.48), 2.81 (2.36-3.34) and 2.33 (2.07-2.62) in 0-0.5, 0.5-1, 1-2, 2-3, 3-5 and ≥5 years after epilepsy diagnosis, respectively]. The recurrent stroke HRs in the epilepsy cohort were >1 from the first [3.06 (2.71-3.34)] to the fourth events [6.33 (1.08-37.03)]. IS events in the epilepsy cohort were associated with a younger onset age, a higher IS severity index, a higher rate of urinary tract infection, a lower in-hospital mortality, while 90-day stroke mortality was similar between the 2 cohorts. CONCLUSION: Since the increased risk of stroke in epilepsy cohort peaked immediately after epilepsy diagnosis, early implementation of prevention strategies is considered.

Zingerone Modulates Neuronal Voltage-Gated Na+ and L-Type Ca2+ Currents.

Zingerone (ZO), a nontoxic methoxyphenol, has been demonstrated to exert various important biological effects. However, its action on varying types of ionic currents and how they concert in neuronal cells remain incompletely understood. With the aid of patch clamp technology, we investigated the effects of ZO on the amplitude, gating, and hysteresis of plasmalemmal ionic currents from both pituitary tumor (GH3) cells and hippocampal (mHippoE-14) neurons. The exposure of the GH3 cells to ZO differentially diminished the peak and late components of the INa. Using a double ramp pulse, the amplitude of the INa(P) was measured, and the appearance of a hysteresis loop was observed. Moreover, ZO reversed the tefluthrin-mediated augmentation of the hysteretic strength of the INa(P) and led to a reduction in the ICa,L. As a double ramp pulse was applied, two types of voltage-dependent hysteresis loops were identified in the ICa,L, and the replacement with BaCl2-attenuated hysteresis of the ICa,L enhanced the ICa,L amplitude along with the current amplitude (i.e., the IBa). The hysteretic magnitude of the ICa,L activated by the double pulse was attenuated by ZO. The peak and late INa in the hippocampal mHippoE-14 neurons was also differentially inhibited by ZO. In addition to acting on the production of reactive oxygen species, ZO produced effects on multiple ionic currents demonstrated herein that, considered together, may significantly impact the functional activities of neuronal cells.

Rufinamide, a Triazole-Derived Antiepileptic Drug, Stimulates Ca2+-Activated K+ Currents While Inhibiting Voltage-Gated Na+ Currents.

Rufinamide (RFM) is a clinically utilized antiepileptic drug that, as a triazole derivative, has a unique structure. The extent to which this drug affects membrane ionic currents remains incompletely understood. With the aid of patch clamp technology, we investigated the effects of RFM on the amplitude, gating, and hysteresis of ionic currents from pituitary GH3 lactotrophs. RFM increased the amplitude of Ca2+-activated K+ currents (IK(Ca)) in pituitary GH3 lactotrophs, and the increase was attenuated by the further addition of iberiotoxin or paxilline. The addition of RFM to the cytosolic surface of the detached patch of membrane resulted in the enhanced activity of large-conductance Ca2+-activated K+ channels (BKCa channels), and paxilline reversed this activity. RFM increased the strength of the hysteresis exhibited by the BKCa channels and induced by an inverted isosceles-triangular ramp pulse. The peak and late voltage-gated Na+ current (INa) evoked by rapid step depolarizations were differentially suppressed by RFM. The molecular docking approach suggested that RFM bound to the intracellular domain of KCa1.1 channels with amino acid residues, thereby functionally affecting BKCa channels' activity. This study is the first to present evidence that, in addition to inhibiting the INa, RFM effectively modifies the IK(Ca), which suggests that it has an impact on neuronal function and excitability.

Immunity, Ion Channels and Epilepsy.

Epilepsy is a common chronic neurological disorder in modern society. One of the major unmet challenges is that current antiseizure medications are basically not disease-modifying. Among the multifaceted etiologies of epilepsy, the role of the immune system has attracted considerable attention in recent years. It is known that both innate and adaptive immunity can be activated in response to insults to the central nervous system, leading to seizures. Moreover, the interaction between ion channels, which have a well-established role in epileptogenesis and epilepsy, and the immune system is complex and is being actively investigated. Some examples, including the interaction between ion channels and mTOR pathways, will be discussed in this paper. Furthermore, there has been substantial progress in our understanding of the pathophysiology of epilepsy associated with autoimmune encephalitis, and numerous neural-specific autoantibodies have been found and documented. Early recognition of immune-mediated epilepsy is important, especially in cases of pharmacoresistant epilepsy and in the presence of signs of autoimmune encephalitis, as early intervention with immunotherapy shows promise.

Editorial to the Special Issue "Electrophysiology".

Ion channels are well recognized to select ions to pass through the cell membrane in a wide variety of cells [...].

The Specific Effects of OD-1, a Peptide Activator, on Voltage-Gated Sodium Current and Seizure Susceptibility.

OD-1, a scorpion toxin, has been previously recognized as an activator of voltage-gated Na+ currents. To what extent this agent can alter hippocampal neuronal Na+ currents and network excitability and how it can be applied to neuronal hyperexcitability research remains unclear. With the aid of patch-clamp technology, it was revealed that, in mHippoE-14 hippocampal neurons, OD-1 produced a concentration-, time-, and state-dependent rise in the peak amplitude of INa. It shifted the INa inactivation curve to a less negative potential and increased the frequency of spontaneous action currents. Further characterization of neuronal excitability revealed higher excitability in the hippocampal slices treated with OD-1 as compared with the control slices. A stereotaxic intrahippocampal injection of OD-1 generated a significantly higher frequency of spontaneous seizures and epileptiform discharges compared with intraperitoneal injection of lithium-pilocarpine- or kainic acid-induced epilepsy, with comparable pathological changes. Carbamazepine significantly attenuated OD-1 induced seizures and epileptiform discharges. The OD-1-mediated modifications of INa altered the electrical activity of neurons in vivo and OD-1 could potentially serve as a novel seizure and excitotoxicity model.

Characterization of the Inhibitory Effect of Gastrodigenin and Gastrodin on M-type K+ Currents in Pituitary Cells and Hippocampal Neurons.

Gastrodigenin (HBA) and gastrodin (GAS) are phenolic ingredients found in Gastrodia elata Blume (GEB), a traditional Chinese herbal medicine. These compounds have been previously used to treat cognitive dysfunction, convulsion, and dizziness. However, at present, there is no available information regarding their potential ionic effects in electrically excitable cells. In the current study, the possible effects of HBA and GAS on different ionic currents in pituitary GH3 cells and hippocampal mHippoE-14 neurons were investigated using the patch-clamp technique. The addition of HBA or GAS resulted in the differential inhibition of the M-type K+ current (IK(M)) density in a concentration-dependent manner in GH3 cells. HBA resulted in a slowing of the activation time course of IK(M), while GAS elevated it. HBA also mildly suppressed the density of erg-mediated or the delayed-rectifier K+ current in GH3 cells. Neither GAS nor HBA (10 µM) modified the voltage-gated Na+ current density, although they suppressed the L-type Ca2+ current density at the same concentration. In hippocampal mHippoE-14 neurons, HBA was effective at inhibiting IK(M) density as well as slowing the activation time course. Taken together, the present study provided the first evidence that HBA or GAS could act on cellular mechanisms, and could therefore potentially have a functional influence in various neurologic disorders.

The Novel Effect of Immunomodulator-Glatiramer Acetate on Epileptogenesis and Epileptic Seizures.

BACKGROUND/AIMS: Immunological mechanisms can be triggered as a response to central nervous system insults and can lead to seizures. In this study an investigation was made to determine if glatiramer acetate (GA), an immunomodulator currently used in the treatment of multiple sclerosis, could protect rats from pilocarpine-induced seizures and chronic epilepsy. METHODS: Two groups of adult male Sprague-Dawley rats, experimental (GA) and control, were used in the study. The systemic IL-1α and IL-1ß levels at baseline were checked as well as status epilepticus (SE), and the spontaneous recurrent seizure (SRS) stage by enzyme-linked immunosorbent assay. The GA group was given GA (150 µg/kg, ip) and the control group was given a saline injection prior to pilocarpine-induced seizures. Seizure susceptibility, severity and mortality were evaluated, using Racine seizure classification and hippocampal damage was evaluated by Nissl staining. The GA group received GA (150 µg/kg/day, ip) daily after SE, and the chronic spontaneous seizures were evaluated by long-term video recording, and mossy fiber sprouting was evaluated by Timm staining. The IL-1α and IL-1ß levels were correlated with seizure activities. The TNF-α level in the hippocampus was determined at the SRS stage by immunohistochemistry. The effect of GA on ionic currents and action potentials (APs) in NG108-15 differentiated neurons was investigated using patch-clamp technology. RESULTS: It was found that latency to severe seizures was significantly longer in the GA (p < 0.01) group, which also had SE of shorter duration and less frequent SRS (p < 0.01). GA attenuated acute hippocampal neuron loss and chronic mossy fiber sprouting in the CA3 and the SRS-reduction correlated with the reduction of IL-1α, but not with IL-1ß or TNF-α levels. Mechanistically, GA reduced the peak amplitude of voltage-gated Na+ current (INa), with a negative shift in the inactivation curve of INa and reduced the amplitude of APs along with decreased firing of APs. CONCLUSION: GA might serve as a neuroexcitability modulator which attenuates pilocarpine-induced acute and chronic excitotoxicity. Sodium channel attenuation was partially independent of the immunomodulatory effect.

Multiple Actions of Rotenone, an Inhibitor of Mitochondrial Respiratory Chain, on Ionic Currents and Miniature End-Plate Potential in Mouse Hippocampal (mHippoE-14) Neurons.

BACKGROUND/AIMS: Rotenone (Rot) is known to suppress the activity of complex I in the mitochondrial chain reaction; however, whether this compound has effects on ion currents in neurons remains largely unexplored. METHODS: With the aid of patch-clamp technology and simulation modeling, the effects of Rot on membrane ion currents present in mHippoE-14 cells were investigated. RESULTS: Addition of Rot produced an inhibitory action on the peak amplitude of INa with an IC50 value of 39.3 µM; however, neither activation nor inactivation kinetics of INa was changed during cell exposure to this compound. Addition of Rot produced little or no modifications in the steady-state inactivation curve of INa. Rot increased the amplitude of Ca2+-activated Cl- current in response to membrane depolarization with an EC50 value of 35.4 µM; further addition of niflumic acid reversed Rot-mediated stimulation of this current. Moreover, when these cells were exposed to 10 µM Rot, a specific population of ATP-sensitive K+ channels with a single-channel conductance of 18.1 pS was measured, despite its inability to alter single-channel conductance. Under current clamp condition, the frequency of miniature end-plate potentials in mHippoE-14 cells was significantly raised in the presence of Rot (10 µM) with no changes in their amplitude and time course of rise and decay. In simulated model of hippocampal neurons incorporated with chemical autaptic connection, increased autaptic strength to mimic the action of Rot was noted to change the bursting pattern with emergence of subthreshold potentials. CONCLUSIONS: The Rot effects presented herein might exert a significant action on functional activities of hippocampal neurons occurring in vivo.

Evidence for the Inhibition by Temozolomide, an Imidazotetrazine Family Alkylator, of Intermediate-Conductance Ca2+-Activated K+ Channels in Glioma Cells.

BACKGROUND: Temozolomide (TMZ), an oral alkylator of the imidazotetrazine family, is used to treat glioma. Whether this drug has any ionic effects in glioma cells remains largely unclear. METHODS: With the aid of patch-clamp technology, we investigated the effects of TMZ on the ionic currents in U373 glioma cells. The mRNA expression of KCNN4 (KCa3.1) in U373 glioma cells and TMZ's effect on K+ currents in these KCNN4 siRNA-transfected U373 cells were investigated. RESULTS: In whole-cell recordings, TMZ decreased the amplitude of voltage-dependent K+ currents (IK) in U373 cells. TMZ-induced IK inhibition was reversed by ionomycin or 1-ethyl-2-benzimidazolinone (1-EBIO). In cell-attached configuration, TMZ concentration-dependently reduced the activity of intermediate-conductance Ca2+-activated K+ (IKCa) channels with an IC50 value of 9.2 µM. Chlorzoxazone or 1-EBIO counteracted the TMZ-induced inhibition of IKCa channels. Although TMZ was unable to modify single-channel conductance, its inhibition of IKCa channels was weakly voltage-dependent and accompanied by a significant prolongation in the slow component of mean closed time. However, neitherlarge-conductance Ca2+-activated (BKCa) nor inwardly rectifying K+ (Kir) channels were affected by TMZ. In current-clamp mode, TMZ depolarized the cell membrane and 1-EBIO reversed TMZ-induced depolarization. TMZ had no effect on IK in KCNN4 siRNA-transfected U373 cells. CONCLUSION: In addition to the DNA damage it does, its inhibitory effect on IKCa channels accompanied by membrane depolarization could be an important mechanism underlying TMZ-induced antineoplastic actions.

Safinamide, an inhibitor of monoamine oxidase, modulates the magnitude, gating, and hysteresis of sodium ion current.

BACKGROUND: Safinamide (SAF), an α-aminoamide derivative and a selective, reversible monoamine oxidase (MAO)-B inhibitor, has both dopaminergic and nondopaminergic (glutamatergic) properties. Several studies have explored the potential of SAF against various neurological disorders; however, to what extent SAF modulates the magnitude, gating, and voltage-dependent hysteresis [Hys(V)] of ionic currents remains unknown. METHODS: With the aid of patch-clamp technology, we investigated the effects of SAF on voltage-gated sodium ion (NaV) channels in pituitary GH3 cells. RESULTS: SAF concentration-dependently stimulated the transient (peak) and late (sustained) components of voltage-gated sodium ion current (INa) in pituitary GH3 cells. The conductance-voltage relationship of transient INa [INa(T)] was shifted to more negative potentials with the SAF presence; however, the steady-state inactivation curve of INa(T) was shifted in a rightward direction in its existence. SAF increased the decaying time constant of INa(T) induced by a train of depolarizing stimuli. Notably, subsequent addition of ranolazine or mirogabalin reversed the SAF-induced increase in the decaying time constant. SAF also increased the magnitude of window INa induced by an ascending ramp voltage Vramp. Furthermore, SAF enhanced the Hys(V) behavior of persistent INa induced by an upright isosceles-triangular Vramp. Single-channel cell-attached recordings indicated SAF effectively increased the open-state probability of NaV channels. Molecular docking revealed SAF interacts with both MAO and NaV channels. CONCLUSION: SAF may interact directly with NaV channels in pituitary neuroendocrine cells, modulating membrane excitability.

Delayed Nonarteritic Posterior Ischemic Optic Neuropathy following Herpes Zoster Ophthalmicus: A Case Report.

Posterior ischemic optic neuropathy (PION), a relatively rare condition, is diagnosed primarily based on the clinical presentation of sudden visual impairment, an optic nerve-related visual field defect, and an initial normal optic disc that corresponds to its pathology of acute ischemia. Among its etiologies, nonarteritic PION is one of the most common causes. Studies on cases of PION associated with herpes zoster ophthalmicus (HZO) are limited, and the diagnosis was made based on the appearance of visual symptoms shortly following rashes. We describe a 64-year-old Asian woman with sudden painless visual loss in the upper half visual field of the left eye 6 weeks after ipsilateral HZO. Within a week, her left vision progressed to total visual loss. Initial examination revealed a near-total visual defect and a normal appearance of the optic disc in the left eye. Laboratory and imaging studies excluded the compressive, infiltrative, or inflammatory etiologies of the left optic nerve. Considering the temporal relationship between the skin rash and visual loss, HZO was the most likely cause of the nonarteritic PION. The patient was given a short course of oral valaciclovir and aspirin. At 6 weeks after the visual loss, an examination revealed stationary visual acuity and visual field defect in the left eye with a pale optic disc, and a retinal nerve fiber loss in the left eye. Compared with previous studies, our case demonstrated a delayed presentation of nonarteritic PION following HZO and broadened the scope of herpes zoster optic neuropathy.

Concerted suppressive effects of carisbamate, an anti-epileptic alkyl-carbamate drug, on voltage-gated Na+ and hyperpolarization-activated cation currents.

Carisbamate (CRS, RWJ-333369) is a new anti-seizure medication. It remains unclear whether and how CRS can perturb the magnitude and/or gating kinetics of membrane ionic currents, despite a few reports demonstrating its ability to suppress voltage-gated Na+ currents. In this study, we observed a set of whole-cell current recordings and found that CRS effectively suppressed the voltage-gated Na+ (INa) and hyperpolarization-activated cation currents (Ih) intrinsically in electrically excitable cells (GH3 cells). The effective IC50 values of CRS for the differential suppression of transient (INa(T)) and late INa (INa(L)) were 56.4 and 11.4 µM, respectively. However, CRS strongly decreased the strength (i.e., Δarea) of the nonlinear window component of INa (INa(W)), which was activated by a short ascending ramp voltage (Vramp); the subsequent addition of deltamethrin (DLT, 10 µM) counteracted the ability of CRS (100 µM, continuous exposure) to suppress INa(W). CRS strikingly decreased the decay time constant of INa(T) evoked during pulse train stimulation; however, the addition of telmisartan (10 µM) effectively attenuated the CRS (30 µM, continuous exposure)-mediated decrease in the decay time constant of the current. During continued exposure to deltamethrin (10 µM), known to be a pyrethroid insecticide, the addition of CRS resulted in differential suppression of the amplitudes of INa(T) and INa(L). The amplitude of Ih activated by a 2-s membrane hyperpolarization was diminished by CRS in a concentration-dependent manner, with an IC50 value of 38 µM. For Ih, CRS altered the steady-state I-V relationship and attenuated the strength of voltage-dependent hysteresis (Hys(V)) activated by an inverted isosceles-triangular Vramp. Moreover, the addition of oxaliplatin effectively reversed the CRS-mediated suppression of Hys(V). The predicted docking interaction between CRS and with a model of the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel or between CRS and the hNaV1.7 channel reflects the ability of CRS to bind to amino acid residues in HCN or hNaV1.7 channel via hydrogen bonds and hydrophobic interactions. These findings reveal the propensity of CRS to modify INa(T) and INa(L) differentially and to effectively suppress the magnitude of Ih. INa and Ih are thus potential targets of the actions of CRS in terms of modulating cellular excitability.

Unilateral non-lesional temporal lobe epilepsy presenting as isolated ictal vertigo: a case report.

Temporal lobe epilepsy is the most common focal epilepsy syndrome and has a broad spectrum of presentations. Nevertheless, isolated vestibular symptoms without other symptoms typical of temporal lobe seizures are relatively rare. Here, we report one female patient who suffered from chronic refractory vertigo and had inappropriate pharmacotherapy for several years. Eventually, epileptic vertigo and dizziness (ictal vertigo) were accurately diagnosed by detailed history taking and serial examinations assisted by sphenoid electroencephalography. Awareness of this unique syndrome is important in the diagnosis of patients with epileptic vertigo and dizziness.

The Roles of Glutamate Receptors and Their Antagonists in Status Epilepticus, Refractory Status Epilepticus, and Super-Refractory Status Epilepticus.

Status epilepticus (SE) is a neurological emergency with a high mortality rate. When compared to chronic epilepsy, it is distinguished by the durability of seizures and frequent resistance to benzodiazepine (BZD). The Receptor Trafficking Hypothesis, which suggests that the downregulation of γ-Aminobutyric acid type A (GABAA) receptors, and upregulation of N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors play major roles in the establishment of SE is the most widely accepted hypothesis underlying BZD resistance. NMDA and AMPA are ionotropic glutamate receptor families that have important excitatory roles in the central nervous system (CNS). They are both essential in maintaining the normal function of the brain and are involved in a variety of neuropsychiatric diseases, including epilepsy. Based on animal and human studies, antagonists of NMDA and AMPA receptors have a significant impact in ending SE; albeit most of them are not yet approved to be in clinically therapeutic guidelines, due to their psychomimetic adverse effects. Although there is still a dearth of randomized, prospective research, NMDA antagonists such as ketamine, magnesium sulfate, and the AMPA antagonist, perampanel, are regarded to be reasonable optional adjuvant therapies in controlling SE, refractory SE (RSE) or super-refractory SE (SRSE), though there are still a lack of randomized, prospective studies. This review seeks to summarize and update knowledge on the SE development hypothesis, as well as clinical trials using NMDA and AMPA antagonists in animal and human studies of SE investigations.

The Role of Glutamate Receptors in Epilepsy.

Glutamate is an essential excitatory neurotransmitter in the central nervous system, playing an indispensable role in neuronal development and memory formation. The dysregulation of glutamate receptors and the glutamatergic system is involved in numerous neurological and psychiatric disorders, especially epilepsy. There are two main classes of glutamate receptor, namely ionotropic and metabotropic (mGluRs) receptors. The former stimulate fast excitatory neurotransmission, are N-methyl-d-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), and kainate; while the latter are G-protein-coupled receptors that mediate glutamatergic activity via intracellular messenger systems. Glutamate, glutamate receptors, and regulation of astrocytes are significantly involved in the pathogenesis of acute seizure and chronic epilepsy. Some glutamate receptor antagonists have been shown to be effective for the treatment of epilepsy, and research and clinical trials are ongoing.