Perampanel inhibits calcitonin gene-related peptide release from rat brainstem in vitro

The broad-spectrum activity of perampanel: state of the art and future perspective of AMPA antagonism beyond epilepsy

Glutamate is the brain's main excitatory neurotransmitter. Glutamatergic neurons primarily compose basic neuronal networks, especially in the cortex. An imbalance of excitatory and inhibitory activities may result in epilepsy or other neurological and psychiatric conditions. Among glutamate receptors, AMPA receptors are the predominant mediator of glutamate-induced excitatory neurotransmission and dictate synaptic efficiency and plasticity by their numbers and/or properties. Therefore, they appear to be a major drug target for modulating several brain functions. Perampanel (PER) is a highly selective, noncompetitive AMPA antagonist approved in several countries worldwide for treating different types of seizures in various epileptic conditions. However, recent data show that PER can potentially address many other conditions within epilepsy and beyond. From this perspective, this review aims to examine the new preclinical and clinical studies-especially those produced from 2017 onwards-on AMPA antagonism and PER in conditions such as mesial temporal lobe epilepsy, idiopathic and genetic generalized epilepsy, brain tumor-related epilepsy, status epilepticus, rare epileptic syndromes, stroke, sleep, epilepsy-related migraine, cognitive impairment, autism, dementia, and other neurodegenerative diseases, as well as provide suggestions on future research agenda aimed at probing the possibility of treating these conditions with PER and/or other AMPA receptor antagonists.

Bioinformatics and network pharmacology analysis of drug targets and mechanisms related to the comorbidity of epilepsy and migraine

OBJECTIVE

The present study aimed to explore the mechanisms underlying the comorbidity of epilepsy and migraine, identify potential common targets for drug intervention, and provide insight into new avenues for disease prevention and treatment using an integrated bioinformatic and network pharmacology approach.

METHODS

Disease targets in epilepsy and migraine were screened using the DisGeNET database to identify intersecting gene targets. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEEG) enrichment analyses were then performed using the WebGestalt database. Furthermore, the STRING database was used to construct a protein-protein interaction (PPI) network, and Cytoscape software was used to analyze the protein molecular signals at the intersection of epilepsy and migraine. The Drugbank database was used to identify common targets for antiepileptic drugs in epilepsy and migraine to further analyze the disease-gene-target-drug interaction network. Finally, molecular docking simulations were performed to verify the hypothesis that migraine and epilepsy share common diseases and drug targets.

RESULTS

A total of 178 common targets for epilepsy and migraine were identified using the DisGeNET database, and the 24 genes most related to the diseases were screened using the Score_gda gene scoring system. GO enrichment analysis indicated that common targets were mainly enriched in biological processes and molecular functions, including membrane potential regulation, inorganic ion transmembrane transport, axonal signaling, and ion channel activity. KEGG pathway enrichment analysis indicated that the mechanism of action might be related to neuroactive ligand receptors, AGE-RAGE, cAMP, and VEGF signaling pathways. The PPI network construction and analysis results showed that the PPI grid had 23 central nodes and 24 connected edges, with an average node degree of 2.09 and an average clustering coefficient of 0.384. The 10 genes with potentially important roles in epilepsy and migraine were CACNA1A, KCNQ2, KCNA1, SCN1A, PRRT2, SCN8A, KCNQ3, SCN2A, GRIN2A, and GABRG2. Drugbank database results indicated that antiepileptic drugs, including lamotrigine, topiramate, valproic acid, carbamazepine, gabapentin, and perampanel, also had common targets with migraine. The three most important targets exhibited strong binding affinity with drugs in the molecular docking simulations.

CONCLUSION

Our systematic and comprehensive analyses of disease-gene-target-drug interaction networks identified several biological processes and molecular functions common to migraine and epilepsy, most of which were related to neuroactive ligand-receptor interactions. These data provide a new theoretical basis and reference for the clinical treatment of comorbid epilepsy and migraine and may aid in the development of novel pharmacological strategies.

Antiseizure Medications for the Prophylaxis of Migraine during the Anti- CGRP Drugs Era

Migraine and epilepsy are fundamentally distinct disorders that can frequently coexist in the same patient. These two conditions significantly differ in diagnosis and therapy but share some widely- used preventive treatments. Antiseizure medications (ASMs) are the mainstay of therapy for epilepsy, and about thirty different ASMs are available to date. ASMs are widely prescribed for other neurological and non-neurological conditions, including migraine. However, only topiramate and valproic acid/valproate currently have an indication for migraine prophylaxis supported by high-quality evidence. Although without specifically approved indications and with a low level of evidence or recommendation, several other ASMs are used for migraine prophylaxis. Understanding ASM antimigraine mechanisms, including their ability to affect the pro-migraine calcitonin gene-related peptide (CGRP) signaling pathway and other pathways, may be instrumental in identifying the specific targets of their antimigraine efficacy and may increase awareness of the neurobiological differences between epilepsy and migraine. Several new ASMs are under clinical testing or have been approved for epilepsy in recent years, providing novel potential drugs for migraine prevention to enrich the treatment armamentarium and drugs that inhibit the CGRP pathway.

Effectiveness of perampanel in managing chronic pain caused by the complex regional pain syndrome: A case report

RATIONALE

The α-amino-3-hydroxy-5-methy-4-isoxazole propionate (AMPA) receptor plays a critical role in the development and persistence of pain, and AMPA receptor antagonists are considered possible therapeutic targets for controlling pain. This report describes a patient with complex regional pain syndrome (CRPS) type I in the right lower leg and foot who responded well to perampanel, an AMPA receptor antagonist, for managing the chronic pain.

PATIENT CONCERN

A 61-year-old woman complained of pain in her right lower leg and foot over a period of 7 year (numeric rating scale: 8) due to CRPS type I.

DIAGNOSIS

CRPS type 1.

INTERVENTIONS

Despite the combination of 300 mg pregabalin, 225 mg/1950 mg tramadol/acetaminophen, and 10 mg nortriptyline per day, her right lower leg and foot were nearly disabled due to the severity of the pain. High-dose prednisolone was found to be ineffective. Then, perampanel (4 mg; 2 mg twice) was administered to this patient daily.

OUTCOMES

The day after treatment with perampanel, her pain completely disappeared. Additionally, at day 7 and 1 month follow-up, she reported no pain in the right lower leg and foot. Moreover, no adverse effects were reported after the application of perampanel.

LESSONS

These results suggest that perampanel may potentially be used to treat centralized pain.

Perampanel may represent an effective treatment for the prevention of migraine comorbid with epilepsy

INTRODUCTION

Migraine is a common comorbidity in patients with epilepsy. Considering the proven associations and the common pathophysiological features linking epilepsy and migraine, some anti-seizure medications (ASMs) have been considered as a treatment for both disorders. This study aimed at assessing both the effectiveness of perampanel (PER) on epileptic seizures and migraine attacks in patients with epilepsy and comorbid migraine, as well as the reduction in the monthly mean rate usage of rescue migraine medications.

METHODS

This observational, multi-centre study included adult patients with epilepsy and comorbid migraine who started PER to better control epileptic seizures and who were followed up for 12 months.

RESULTS

Thirty-one patients were included (mean age 40.13 ± 13.13 years; 67.0% female). At the 12-month follow-up visit, 27 patients were continuing PER concomitantly with 1 (45.2%) or 2 ASMs (54.8%). A significant reduction in epileptic seizures, migraine attacks, and the monthly use of rescue migraine medications between baseline and both 6- and 12-month follow-up visits was documented.

CONCLUSION

PER demonstrated good effectiveness in reducing both epileptic seizures and migraine attacks in patients with comorbid epilepsy and migraine. Future studies with possibly larger samples are needed to evaluate the efficacy of PER in migraine other than epilepsy.

Headache in people with epilepsy

Epidemiological estimates indicate that individuals with epilepsy are more likely to experience headaches, including migraine, than individuals without epilepsy. Headaches can be temporally unrelated to seizures, or can occur before, during or after an episode; seizures and migraine attacks are mostly not temporally linked. The pathophysiological links between headaches (including migraine) and epilepsy are complex and have not yet been fully elucidated. Correct diagnoses and appropriate treatment of headaches in individuals with epilepsy is essential, as headaches can contribute substantially to disease burden. Here, we review the insights that have been made into the associations between headache and epilepsy over the past 5 years, including information on the pathophysiological mechanisms and genetic variants that link the two disorders. We also discuss the current best practice for the management of headaches co-occurring with epilepsy and highlight future challenges for this area of research.

Analgesic and Anti-Inflammatory Effects of Perampanel in Acute and Chronic Pain Models in Mice: Interaction With the Cannabinergic System

Pain conditions, such as neuropathic pain (NP) and persistent inflammatory pain are therapeutically difficult to manage. Previous studies have shown the involvement of glutamate receptor in pain modulation and in particular same of these showed the key role of the AMPA ionotropic glutamate receptor subtype. Antiseizure medications (ASMs) are often used to treat this symptom, however the effect of perampanel (PER), an ASM acting as selective, non-competitive inhibitor of the AMPA receptor on the management of pain has not well been investigated yet. Here we tested the potential analgesic and anti-inflammatory effects of PER, in acute and chronic pain models. PER was given orally either in acute (5 mg/kg) or repeated administration (3 mg/kg/d for 4 days). Pain response was assessed using models of nociceptive sensitivity, visceral and inflammatory pain, and mechanical allodynia and hyperalgesia induced by chronic constriction injury to the sciatic nerve. PER significantly reduced pain perception in all behavioral tests as well as CCI-induced mechanical allodynia and hyperalgesia in acute regimen (5 mg/kg). This effect was also observed after repeated treatment using the dose of 3 mg/kg/d. The antinociceptive, antiallodynic and antihyperalgesic effects of PER were attenuated when the CB₁ antagonist AM251 (1 mg/kg/i.p.) was administered before PER treatment, suggesting the involvement of the cannabinergic system. Moreover, Ex vivo analyses showed that PER significantly increased CB₁ receptor expression and reduced inflammatory cytokines (i.e. TNFα, IL-1β, and IL-6) in the spinal cord. In conclusion, these results extend our knowledge on PER antinociceptive and antiallodynic effects and support the involvement of cannabinergic system on its mode of action.

Intrathecally administered perampanel alleviates neuropathic and inflammatory pain in rats

Chronic pain conditions such as neuropathic pain and persistent inflammatory pain are difficult to manage. Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors modulate nociceptive processing at the spinal dorsal horn. Previous studies have shown that intrathecal AMPA receptor antagonists exert antinociception in various pain states. Perampanel is a selective, noncompetitive inhibitor of the AMPA receptor and used clinically as an antiepileptic drug. Little is known about antinociceptive action of perampanel in the spinal cord. Here, we explored whether intrathecal perampanel attenuates neuropathic and inflammatory pain. A chronic constriction injury (CCI) to the sciatic nerve was induced in male Sprague-Dawley rats. We evaluated the effects of intrathecal perampanel (10, 30, or 100 μg) on mechanical and cold hyperalgesia using the electronic von Frey and cold plate tests, respectively. Normal rats were assessed in terms of inflammatory nociception using the formalin test, and motor function employing the rotarod test. In the CCI rats, spinally applied perampanel inhibited mechanical and cold hyperalgesia dose-dependently. In normal rats, perampanel remarkably suppressed the early- and late-phase responses in the formalin test, and it weakly affected motor performance for a short period at the highest dose. These results suggest that perampanel exerts antinociceptive actions on neuropathic and persistent inflammatory pain in the spinal cord. Perampanel may be safe and beneficial remedy for patients with such pain conditions. In addition, AMPA receptor can be a promising target for treatment of chronic pain.

The Novel Direct Modulatory Effects of Perampanel, an Antagonist of AMPA Receptors, on Voltage-Gated Sodium and M-type Potassium Currents

Perampanel (PER) is a selective blocker of AMPA receptors showing efficacy in treating various epileptic disorders including brain tumor-related epilepsy and also potential in treating motor neuron disease. However, besides its inhibition of AMPA-induced currents, whether PER has any other direct ionic effects in different types of neurons remains largely unknown. We investigated the effects of PER and related compounds on ionic currents in different types of cells, including hippocampal mHippoE-14 neurons, motor neuron-like NSC-34 cells and U87 glioma cells. We found that PER differentially and effectively suppressed the amplitude of voltage-gated Na⁺ currents (I_Na) in mHippoE-14 cells. The IC₅₀ values required to inhibit peak and late I_Na were 4.12 and 0.78 μM, respectively. PER attenuated tefluthrin-induced increases in both amplitude and deactivating time constant of I_Na. Importantly, PER also inhibited the amplitude of M-type K⁺ currents (I_K(M)) with an IC₅₀ value of 0.92 μM. The suppression of I_K(M) was attenuated by the addition of flupirtine or ZnCl₂ but not by L-quisqualic acid or sorafenib. Meanwhile, in cell-attached configuration, PER (3 μM) decreased the activity of M-type K⁺ channels with no change in single-channel conductance but shifting the activation curve along the voltage axis in a rightward direction. Supportively, PER suppressed I_K(M) in NSC-34 cells and I_Na in U87 glioma cells. The inhibitory effects of PER on both I_Na and I_K(M), independent of its antagonistic effect on AMPA receptors, may be responsible for its wide-spectrum of effects observed in neurological clinical practice.