N-methyl-d-aspartate receptor antagonists for migraine: A potential therapeutic approach

Molecular assessment of NMDAR subunits and neuronal apoptosis in the trigeminal ganglion in a model of male migraine-induced rats following Moringa oleifera alcoholic extract administration

INTRODUCTION

Migraine, a common disorder marked by severe and repetitive headaches, has been linked to the involvement of the NMDA receptor (NMDAR), a receptor responsible for glutamate signaling. Moringa oleifera (M. oleifera), recognized for its anti-inflammatory properties and therapeutic potential in various conditions, has been investigated. This study aims to assess the efficacy and precise mechanisms of M. oleifera for the treatment of migraine, for which evidence is limited.

METHODS

Rats were stratified into four distinct groups. The control group did not undergo the migraine-induction protocol. Post-induction, the "sumatriptan" group was administered sumatriptan injections, the "treatment" group received oral M. oleifera extract, and the "vehicle" group was provided with oral solvent treatment. Behavioral evaluations encompassing Von Frey's and hot plate assessments, in addition to qPCR analysis targeting Nr2a, Nr2b, Bax, Bcl-2, and Caspase-3, were conducted.

RESULTS

Von Fery's and hot plate tests revealed a notable decrease in triggering pressure and temperature within the vehicle group when compared to the other groups (both ps < 0.001). The Nr2a expression levels in both the vehicle and treatment cohorts exhibited significantly higher values than those observed in the control group (p < 0.001, p = 0.001) and the sumatriptan group (p < 0.001, p = 0.002). Conversely, no substantial alterations in Nr2b or Bcl-2 expression levels were observed across the study groups (p = 0.404, p = 0.976). Notably, heightened expressions of Caspase-3 and Bax were evident in the vehicle group relative to the other groups (p = 0.013, p = 0.010).

CONCLUSIONS

Moringa oleifera extract appears to mitigate symptoms of migraine by inhibiting apoptosis, suggesting potential efficacy in migraine treatment; however, additional research investigating a wider range of pathways is necessary.

CLINICAL TRIAL NUMBER

Not applicable.

The prodrome of migraine: mechanistic insights and emerging therapeutic strategies

Migraine is a common clinical chronic neurovascular disease characterized by recurrent, mostly unilateral, moderate or severe, pulsatile headache. It can be divided into four clinical stages: premonitory (prodrome), aura, headache and postdrome. The early warning value of the prodrome in migraine has been largely verified in various studies. In fact, the prodrome of migraine has received increasing attention as it can serve as an ideal therapeutic window for early intervention and effective treatment of migraine. In recent years, the pathophysiological and molecular biological mechanisms in the prodromal stage of migraine have been extensively studied, and great progress has been made in understanding the disease. This review paper aims to provide an overview of recent studies mainly focused on the prodrome of migraine, discuss the biological mechanisms underlying the clinical profile, and reveal novel therapeutic strategies for preventing or blocking migraine onset during its prodrome.

Targeting Peripheral N-Methyl-D-Aspartate Receptor (NMDAR): A Novel Strategy for the Treatment of Migraine

Backgrounds: Several acute and preventive medications were developed for the treatment of migraine. Yet, a significant proportion of patients reports an inadequate response and a lack of tolerability, emphasizing the need for new options. Glutamate is the most important excitatory neurotransmitter in the brain, and glutamate receptors including N-Methyl-D-Aspartate Receptor (NMDAR) are expressed at several levels of the trigeminovascular system, which is the anatomical and physiological substrate of migraine pain. Objective: To review preclinical and clinical studies investigating the role of the NMDAR in migraine pathophysiology. Methods: No protocol was registered for this study. References for the present review were identified from a narrative search of the PubMed database. Search terms such as glutamate, migraine, N-Methyl-D-Aspartate Receptor, and NMDAR were used. No restrictions were made in terms of the language and date of publication. Results: In animal models, administration of monosodium glutamate (MSG) activated and sensitized trigeminovascular neurons. In healthy human participants, consumption of MSG caused headaches, craniofacial sensitivity, and nausea. In in vivo models and through immunolabeling, NMDAR subunits NR1, NR2A, and NR2B were expressed in trigeminal ganglion neurons. In humans, NMDAR antagonists such as ketamine and memantine caused a significant reduction in pain intensity and monthly headache frequency. Conclusions: Accumulative evidence indicates that NMDAR is a promising new target for the treatment of migraine. Selective NMDAR antagonists without central effects are needed to investigate their therapeutic benefit in the treatment of migraine.

Migraine signaling pathways: amino acid metabolites that regulate migraine and predispose migraineurs to headache

Migraine is a common, debilitating disorder for which attacks typically result in a throbbing, pulsating headache. Although much is known about migraine, its complexity renders understanding the complete etiology currently out of reach. However, two important facts are clear, the brain and the metabolism of the migraineur differ from that of the non-migraineur. This review centers on the altered amino acid metabolism in migraineurs and how it helps define the pathology of migraine.

Integrating Pathophysiology in Migraine: Role of the Gut Microbiome and Melatonin

BACKGROUND

The pathoetiology and pathophysiology of migraine are widely accepted as unknown.

METHODS

The current article reviews the wide array of data associated with the biological underpinnings of migraine and provides a framework that integrates previously disparate bodies of data.

RESULTS

The importance of alterations in stress- and pro-inflammatory cytokine- induced gut dysbiosis, especially butyrate production, are highlighted. This is linked to a decrease in the availability of melatonin, and a relative increase in the N-acetylserotonin/melatonin ratio, which has consequences for the heightened glutamatergic excitatory transmission in migraine. It is proposed that suboptimal mitochondria functioning and metabolic regulation drive alterations in astrocytes and satellite glial cells that underpin the vasoregulatory and nociceptive changes in migraine.

CONCLUSION

This provides a framework not only for classical migraine associated factors, such as calcitonin-gene related peptide and serotonin, but also for wider factors in the developmental pathoetiology of migraine. A number of future research and treatment implications arise, including the clinical utilization of sodium butyrate and melatonin in the management of migraine.

Intravenous dextromethorphan/quinidine inhibits activity of dura-sensitive spinal trigeminal neurons in rats

BACKGROUND

Migraine is a chronic neurological disorder characterized by episodes of throbbing headaches. Practically all medications currently used in migraine prophylaxis have a number of substantial disadvantages and use limitations. Therefore, the further search for principally new prophylactic antimigraine agents remains an important task. The objective of our study was to evaluate the effects of a fixed combination of dextromethorphan hydrobromide and quinidine sulphate (DM/Q) on activity of the spinal trigeminal neurons in an electrophysiological model of trigemino-durovascular nociception.

METHODS

The study was performed in 15 male Wistar rats, which were anaesthetized with urethane/α-chloralose and paralysed using pipecuronium bromide. The effects of cumulative intravenous infusions of DM/Q (three steps performed 30 min apart, 15/7.5 mg/kg of DM/Q in 0.5 mL of isotonic saline per step) on ongoing and dural electrical stimulation-induced neuronal activities were tested in a group of eight rats over 90 min. Other seven animals received cumulative infusion of equal volumes of saline and served as control.

RESULTS

Cumulative administration of DM/Q produced steady suppression of both the ongoing activity of the spinal trigeminal neurons and their responses to electrical stimulation of the dura mater.

CONCLUSIONS

It is evident that the observed DM/Q-induced suppression of trigeminal neuron excitability can lead to a reduction in nociceptive transmission from meninges to higher centres of the brain. Since the same mechanism is believed to underlie the pharmacodynamics of many well-known antimigraine drugs, results of the present study enable us to anticipate the potential efficacy of DM/Q in migraine.

Preventive effects of AdR-siPTEN through the regulation of NMDA receptor NR2B subunit in trigeminal ganglia of migraine rats

OBJECTIVE

Migraine is a refractory disease that is due to neuronal hyperexcitability, and has high incidence, mortality, and disability rates. The N-methyl-D-aspartate receptor 2B (NR2B) subunit has been found to play an important role in the pathogenesis of migraine. There is evidence suggesting that a tumor suppressor phosphatase and tensin homolog (PTEN) can confer a neuroprotective effect on cerebral ischemic injury by regulating NR2B levels. However, the role of PTEN in migraines is still unclear. This study aimed to define whether PTEN is involved in the pathogenesis of migraine through modulating NR2B, nitric oxide synthase (NOS), and nitric oxide (NO) in the trigeminal ganglia of rats with glyceryl trinitrate-induced migraine.

METHODS

Adenovirus-expressing siPTEN or RFP was independently injected into the Sp5 (spinal trigeminal nucleus) of rats suffering from migraines. Seven days later, tactile sensory testing was performed to detect the tactile threshold. Immunofluorescence assay, western blot assay, RT-PCR, and biochemical examination were done to measure PTEN, NR2B, NOS, and NO levels in the trigeminal ganglia of migraine rats.

RESULTS

NR2B, NOS, and NO levels significantly (P<0.05) decreased in the trigeminal ganglia of migraine-affected rats pretreated with adenovirus-expressing siPTEN.

CONCLUSION

These results suggest that PTEN in trigeminal ganglia is implicated in the pathogenesis of migraine, and PTEN may be a novel and promising candidate for future treatment and/or prevention of migraine via regulating NR2B and decreasing NO production in trigeminal ganglia.

NMDA Receptor Antagonists for Treatment of Depression

Depression is a psychiatric disorder that affects millions of people worldwide. Individuals battling this disorder commonly experience high rates of relapse, persistent residual symptoms, functional impairment, and diminished well-being. Medications have important utility in stabilizing moods and daily functions of many individuals. However, only one third of patients had considerable improvement with a standard antidepressant after 2 months and all patients had to deal with numerous side effects. The N-methyl-d-aspartate (NMDA) receptor family has received special attention because of its critical role in psychiatric disorders. Direct targeting of the NMDA receptor could result in more rapid antidepressant effects. Antidepressant-like effects of NMDA receptor antagonists have been demonstrated in different animal models. MK-801 (a use-dependent channel blocker), and CGP 37849 (an NMDA receptor antagonist) have shown antidepressant properties in preclinical studies, either alone or combined with traditional antidepressants. A recent development is use of ketamine clinically for refractory depression. The purpose of this review is to examine and analyze current literature on the role of NMDA receptor antagonists for treatment of depression and whether this is a feasible route in drug discovery.