5-hydroxytryptamine in migraine: The puzzling role of ionotropic 5-HT3 receptor in the context of established therapeutic effect of metabotropic 5-HT1 subtypes

Investigation of the effect of Ramadan fasting on serum levels of melatonin, cortisol, and serotonin: the case of Turkey

INTRODUCTION

The aim of this study is to examine the effects of Ramadan fasting on melatonin, cortisol, and serotonin levels.

METHODS

In this study, the blood of 19 healthy male individuals between the ages of 26 and 51, registered in Agri (Turkey) Family Health Center and fasting during Ramadan, was studied. The study was carried out in 2021-2022. The SPSS-22 package program was used in the analysis of the data. Wilcoxon analysis was used in the study.

RESULTS

It was determined that the pre-test-post-test melatonin and cortisol levels of the individuals were not statistically significant (p>0.05). It was determined that the pre-test-post-test serotonin difference of the individuals was statistically significant (p<0.05).

CONCLUSION

It has been determined that Ramadan fasting increases the serotonin level of individuals but does not change the levels of melatonin and cortisol. It was determined that the level of happiness of individuals increased after Ramadan fasting. Longitudinal studies on the effects of Ramadan fasting are recommended.

Rizatriptan benzoate-loaded dissolving microneedle patch for management of acute migraine therapy

In this study, dissolving microneedles (MNs) using polyvinyl alcohol (PVA) and poly (1-vinylpyrrolidone-co-vinyl acetate) (P(VP-co-VA)) as matrix materials were developed for transdermal delivery of rizatriptan benzoate (RB) for acute migraine treatment. In-vitro permeation studies were conducted to assess the feasibility of the as-fabricated dissolving MNs to release RB. Drug skin penetration were tested by Franz diffusion cells, showing an increase of the transdermal flux compared to passive diffusion due to the as-fabricated dissolving MNs having a sufficient mechanical strength to penetrate the skin and form microchannels. The pharmacological study in vivo showed that RB-loaded dissolving MNs significantly alleviated migraine-related response by up-regulating the level of 5-hydroxytryptamine (5-HT) and down-regulating the levels of calcitonin gene-related peptide (CGRP) and substance P (SP). In conclusion, the RB-loaded dissolving MNs have advantages of safety, convenience, and high efficacy over conventional administrations, laying a foundation for the transdermal drug delivery system treatment for acute migraine.

D2 dopamine receptor-mediated mechanisms of dopaminergic system modulation in in vivo and in vitro experimental models of migraine

The dopaminergic system is implicated in the pathophysiology of migraine. However, the underlying mechanisms remain unclear. We explored the effects and mechanisms of dopaminergic system modulation in the in vivo and in vitro rat models of migraine. Dopaminergic agonist apomorphine, D2 receptor antagonists metoclopramide and haloperidol and 5-HT3 receptor antagonist ondansetron alone and together were tested in nitroglycerin-induced migraine model, in vivo. Likewise, the combinations of drugs were also tested on basal calcitonin gene-related peptide (CGRP) release in vitro hemiskull preparations. Mechanical allodynia was tested by von Frey filaments. CGRP concentrations in trigeminovascular structures and in vitro superfusates and c-Fos levels in the brainstem were determined by enzyme-linked immunosorbent assay. Meningeal mast cells were evaluated with toluidine blue staining. Apomorphine further enhanced nitroglycerin-induced mechanical allodynia, brainstem c-fos expression, trigeminal ganglion and brainstem CGRP concentrations and meningeal mast cell degranulation, in vivo. Haloperidol completely antagonised all apomorphine-induced effects and also alleviated changes induced by nitroglycerin without apomorphine. Metoclopramide and ondansetron partially attenuated apomorphine- or nitroglycerin-induced effects. A combination of haloperidol and ondansetron decreased basal CGRP release, in vitro, whereas the other administrations were ineffective. Apomorphine-mediated dopaminergic activation exacerbated nitroglycerin-stimulated nociceptive reactions by further enhancing c-fos expression, CGRP release and mast cell degranulation in strategical structures associated with migraine pain. Metoclopramide partially attenuated the effects of apomorphine, most likely because it is also a 5-HT3 receptor antagonist. Haloperidol with pure D2 receptor antagonism feature appears to be more effective than metoclopramide in reducing migraine-related parameters in dopaminergic activation- and/or NTG-induced migraine-like conditions.

Mechanosensitive receptors in migraine: a systematic review

BACKGROUND

Migraine is a debilitating neurological disorder with pain profile, suggesting exaggerated mechanosensation. Mechanosensitive receptors of different families, which specifically respond to various mechanical stimuli, have gathered increasing attention due to their potential role in migraine related nociception. Understanding these mechanisms is of principal importance for improved therapeutic strategies. This systematic review comprehensively examines the involvement of mechanosensitive mechanisms in migraine pain pathways.

METHODS

A systematic search across the Cochrane Library, Scopus, Web of Science, and Medline was conducted on 8th August 2023 for the period from 2000 to 2023, according to PRISMA guidelines. The review was constructed following a meticulous evaluation by two authors who independently applied rigorous inclusion criteria and quality assessments to the selected studies, upon which all authors collectively wrote the review.

RESULTS

We identified 36 relevant studies with our analysis. Additionally, 3 more studies were selected by literature search. The 39 papers included in this systematic review cover the role of the putative mechanosensitive Piezo and K2P, as well as ASICs, NMDA, and TRP family of channels in the migraine pain cascade. The outcome of the available knowledge, including mainly preclinical animal models of migraine and few clinical studies, underscores the intricate relationship between mechanosensitive receptors and migraine pain symptoms. The review presents the mechanisms of activation of mechanosensitive receptors that may be involved in the generation of nociceptive signals and migraine associated clinical symptoms. The gender differences of targeting these receptors as potential therapeutic interventions are also acknowledged as well as the challenges related to respective drug development.

CONCLUSIONS

Overall, this analysis identified key molecular players and uncovered significant gaps in our understanding of mechanotransduction in migraine. This review offers a foundation for filling these gaps and suggests novel therapeutic options for migraine treatments based on achievements in the emerging field of mechano-neurobiology.

The 5-HT1F receptor as the target of ditans in migraine - from bench to bedside

Migraine is a leading cause of disability in more than one billion people worldwide, yet it remains universally underappreciated, even by individuals with the condition. Among other shortcomings, current treatments (often repurposed agents) have limited efficacy and potential adverse effects, leading to low treatment adherence. After the introduction of agents that target the calcitonin gene-related peptide pathway, another new drug class, the ditans - a group of selective serotonin 5-HT_1F receptor agonists - has just reached the international market. Here, we review preclinical studies from the late 1990s and more recent clinical research that contributed to the development of the ditans and led to their approval for acute migraine treatment by the US Food and Drug Administration and the European Medicines Agency.

Systematic review and meta-analysis of calculating degree of comorbidity of irritable bowel syndrome with migraine

BACKGROUND

Irritable bowel syndrome (IBS) and migraines are often comorbid each other. These disorders are likely to be bidirectionally linked through the gut-brain axis and share several underlying mechanisms including central nervous system sensitization. However, quantitative analysis of comorbidity was not reported enough. The aim of this systematic review and meta-analysis was to calculate the present degree of comorbidity of these two disorders.

METHODS

A literature search was performed searching for articles describing IBS or migraine patients with the same inverse comorbidity. Pooled odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (CIs) were then extracted. The total effect estimates were determined and presented by random effect forest plots for the group of articles with IBS patients with migraine and the group of articles on migraine sufferers with comorbid IBS separately. The average results of these plots were compared.

RESULTS

The literature search resulted in initial 358 articles and final 22 articles for the meta-analysis. The total OR values obtained were 2.09 [1.79 - 2.43] in IBS with comorbid migraine or headache, 2.51 [1.76 - 3.58] for migraineurs with comorbid IBS and an overall HR of 1 .62 [1.29 - 2.03] was found for cohort studies of migraine sufferers with comorbid IBS. A similar expression of a selection of other comorbidities was found in IBS and migraine patients, especially for depression and fibromyalgia a strong similarity was found in their expression rate.

CONCLUSIONS

This systematic review with meta-analysis was the first to combine data on IBS patients with comorbid migraine and migraineurs with comorbid IBS. The fact that closely related existential rates were observed between these two groups should be used as motivation for future research to further investigate these disorders for why this similarity occurs. Mechanisms involved in central hypersensitivity such as genetic risk factors, mitochondrial dysfunction and microbiota are particularly good candidates. Experimental designs in which therapeutic methods for these conditions can be exchanged or combined may also lead to the discovery of more efficient treatment methods.

Glia Signaling and Brain Microenvironment in Migraine

Migraine is a complicated neurological disorder affecting 6% of men and 18% of women worldwide. Various mechanisms, including neuroinflammation, oxidative stress, altered mitochondrial function, neurotransmitter disturbances, cortical hyperexcitability, genetic factors, and endocrine system problems, are responsible for migraine. However, these mechanisms have not completely delineated the pathophysiology behind migraine, and they should be further studied. The brain microenvironment comprises neurons, glial cells, and vascular structures with complex interactions. Disruption of the brain microenvironment is the main culprit behind various neurological disorders. Neuron-glia crosstalk contributes to hyperalgesia in migraine. In the brain, microenvironment and related peripheral regulatory circuits, microglia, astrocytes, and satellite cells are necessary for proper function. These are the most important cells that could induce migraine headaches by disturbing the balance of the neurotransmitters in the nervous system. Neuroinflammation and oxidative stress are the prominent reactions glial cells drive during migraine. Understanding the role of cellular and molecular components of the brain microenvironment on the major neurotransmitters engaged in migraine pathophysiology facilitates the development of new therapeutic approaches with higher effectiveness for migraine headaches. Investigating the role of the brain microenvironment and neuroinflammation in migraine may help decipher its pathophysiology and provide an opportunity to develop novel therapeutic approaches for its management. This review aims to discuss the neuron-glia interactions in the brain microenvironment during migraine and their potential role as a therapeutic target for the treatment of migraine.

Role of ATP in migraine mechanisms: focus on P2X3 receptors

Migraine is a major health burden worldwide with complex pathophysiology and multifarious underlying mechanisms. One poorly understood issue concerns the early steps in the generation of migraine pain. To elucidate the basic process of migraine pain further, it seems useful to consider key molecular players that may operate synergistically to evoke headache. While the neuropeptide CGRP is an important contributor, we propose that extracellular ATP (that generally plays a powerful nociceptive role) is also a major component of migraine headache, acting in concert with CGRP to stimulate trigeminal nociceptive neurons. The aim of the present focused review is to highlight the role of ATP activating its P2X3 membrane receptors selectively expressed by sensory neurons including their nerve fiber terminals in the meninges. Specifically, we present data on the homeostasis of ATP and related purines in the trigeminovascular system and in the CNS; the basic properties of ATP signalling at peripheral and central nerve terminals; the characteristics of P2X3 and related receptors in trigeminal neurons; the critical speed and persistence of P2X3 receptor activity; their cohabitation at the so-called meningeal neuro-immune synapse; the identity of certain endogenous agents cooperating with ATP to induce neuronal sensitization in the trigeminal sensory system; the role of P2X3 receptors in familial type migraine; the current state of P2X3 receptor antagonists and their pharmacological perspectives in migraine. It is proposed that the unique kinetic properties of P2X3 receptors activated by ATP offer an interesting translational value to stimulate future studies for innovative treatments of migraine pain.

Activation of Meningeal Afferents Relevant to Trigeminal Headache Pain after Photothrombotic Stroke Lesion: A Pilot Study in Mice

Stroke can be followed by immediate severe headaches. As headaches are initiated by the activation of trigeminal meningeal afferents, we assessed changes in the activity of meningeal afferents in mice subjected to cortical photothrombosis. Cortical photothrombosis induced ipsilateral lesions of variable sizes that were associated with contralateral sensorimotor impairment. Nociceptive firing of mechanosensitive Piezo1 channels, activated by the agonist Yoda1, was increased in meningeal afferents in the ischemic hemispheres. These meningeal afferents also had a higher maximal spike frequency at baseline and during activation of the mechanosensitive Piezo1 channel by Yoda1. Moreover, in these meningeal afferents, nociceptive firing was active during the entire induction of transient receptor potential vanilloid 1 (TRPV1) channels by capsaicin. No such activation was observed on the contralateral hemi-skulls of the same group of mice or in control mice. Our data suggest the involvement of mechanosensitive Piezo1 channels capable of maintaining high-frequency spiking activity and of nociceptive TRPV1 channels in trigeminal headache pain responses after experimental ischemic stroke in mice.

The neurobiology of pain and facial movements in rodents: Clinical applications and current research

One of the most controversial aspects of the use of animals in science is the production of pain. Pain is a central ethical concern. The activation of neural pathways involved in the pain response has physiological, endocrine, and behavioral consequences, that can affect both the health and welfare of the animals, as well as the validity of research. The strategy to prevent these consequences requires understanding of the nociception process, pain itself, and how assessment can be performed using validated, non-invasive methods. The study of facial expressions related to pain has undergone considerable study with the finding that certain movements of the facial muscles (called facial action units) are associated with the presence and intensity of pain. This review, focused on rodents, discusses the neurobiology of facial expressions, clinical applications, and current research designed to better understand pain and the nociceptive pathway as a strategy for implementing refinement in biomedical research.

Peripheral N-methyl-D-aspartate receptor activation contributes to monosodium glutamate-induced headache but not nausea behaviours in rats

Monosodium glutamate induces behaviors thought to reflect headache and nausea in rats. We explored the effects of the N-methyl-d-aspartate receptor antagonist (2R)-amino-5-phosphonovaleric acid, the inotropic glutamate receptor antagonist kynurenic acid, and the CGRP receptor antagonist olcegepant, on monosodium glutamate-induced increases in nocifensive, headache-like and nausea behaviours. Effects of these antagonists on motor function were examined with a rotarod. The effect of the dopamine receptor antagonist metoclopramide and the serotonin 3 receptor antagonist ondansetron on nausea behaviour was also assessed. (2R)-amino-5-phosphonovaleric acid, and to a lesser extent, kynurenic acid and olcegepant, reduced nocifensive and headache-like behaviours evoked by monosodium glutamate. No alteration in motor function by (2R)-amino-5-phosphonovaleric acid, kynurenic acid or olcegepant was observed. No sex-related differences in the effectiveness of these agents were identified. Nausea behaviour was significantly more pronounced in male than in female rats. Olcegepant, ondansetron and metoclopramide ameliorated this nausea behaviour in male rats. Ondansetron and metoclopramide also reduced headache-like behaviour in male rats. These findings suggest that peripheral N-methyl-d-aspartate receptor activation underlies monosodium glutamate-induced headache-like behaviour but does not mediate the nausea behaviour in rats.

Inhibiting Endocannabinoid Hydrolysis as Emerging Analgesic Strategy Targeting a Spectrum of Ion Channels Implicated in Migraine Pain

Migraine is a disabling neurovascular disorder characterized by severe pain with still limited efficient treatments. Endocannabinoids, the endogenous painkillers, emerged, alternative to plant cannabis, as promising analgesics against migraine pain. In this thematic review, we discuss how inhibition of the main endocannabinoid-degrading enzymes, monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), could raise the level of endocannabinoids (endoCBs) such as 2-AG and anandamide in order to alleviate migraine pain. We describe here: (i) migraine pain signaling pathways, which could serve as specific targets for antinociception; (ii) a divergent distribution of MAGL and FAAH activities in the key regions of the PNS and CNS implicated in migraine pain signaling; (iii) a complexity of anti-nociceptive effects of endoCBs mediated by cannabinoid receptors and through a direct modulation of ion channels in nociceptive neurons; and (iv) the spectrum of emerging potent MAGL and FAAH inhibitors which efficiently increase endoCBs levels. The specific distribution and homeostasis of endoCBs in the main regions of the nociceptive system and their generation ‘on demand’, along with recent availability of MAGL and FAAH inhibitors suggest new perspectives for endoCBs-mediated analgesia in migraine pain.

Testing the Role of Glutamate NMDA Receptors in Peripheral Trigeminal Nociception Implicated in Migraine Pain

The pro-nociceptive role of glutamate in the CNS in migraine pathophysiology is well established. Glutamate, released from trigeminal afferents, activates second order nociceptive neurons in the brainstem. However, the function of peripheral glutamate receptors in the trigeminovascular system suggested as the origin site for migraine pain, is less known. In the current project, we used calcium imaging and patch clamp recordings from trigeminal ganglion (TG) neurons, immunolabelling, CGRP assay and direct electrophysiological recordings from rat meningeal afferents to investigate the role of glutamate in trigeminal nociception. Glutamate, aspartate, and, to a lesser extent, NMDA under free-magnesium conditions, evoked calcium transients in a fraction of isolated TG neurons, indicating functional expression of NMDA receptors. The fraction of NMDA sensitive neurons was increased by the migraine mediator CGRP. NMDA also activated slowly desensitizing currents in 37% of TG neurons. However, neither glutamate nor NMDA changed the level of extracellular CGRP. TG neurons expressed both GluN2A and GluN2B subunits of NMDA receptors. In addition, after removal of magnesium, NMDA activated persistent spiking activity in a fraction of trigeminal nerve fibers in meninges. Thus, glutamate activates NMDA receptors in somas of TG neurons and their meningeal nerve terminals in magnesium-dependent manner. These findings suggest that peripherally released glutamate can promote excitation of meningeal afferents implicated in generation of migraine pain in conditions of inherited or acquired reduced magnesium blockage of NMDA channels and support the usage of magnesium supplements in migraine.

Migraine-relevant sex-dependent activation of mouse meningeal afferents by TRPM3 agonists

Background

Migraine is a common brain disorder that predominantly affects women. Migraine pain seems mediated by the activation of mechanosensitive channels in meningeal afferents. Given the role of transient receptor potential melastatin 3 (TRPM3) channels in mechanical activation, as well as hormonal regulation, these channels may play a role in the sex difference in migraine. Therefore, we investigated whether nociceptive firing induced by TRPM3 channel agonists in meningeal afferents was different between male and female mice. In addition, we assessed the relative contribution of mechanosensitive TRPM3 channels and that of mechanosensitive Piezo1 channels and transient receptor potential vanilloid 1 (TRPV1) channels to nociceptive firing relevant to migraine in both sexes.

Methods

Ten- to 13-week-old male and female wildtype (WT) C57BL/6 J mice were used. Nociceptive spikes were recorded directly from nerve terminals in the meninges in the hemiskull preparations.

Results

Selective agonists of TRPM3 channels profoundly activated peripheral trigeminal nerve fibres in mouse meninges. A sex difference was observed for nociceptive firing induced by either PregS or CIM0216, both agonists of TRPM3 channels, with the induced firing being particularly prominent for female mice. Application of Yoda1, an agonist of Piezo1 channels, or capsaicin activating TRPV1 channels, although also leading to increased nociceptive firing of meningeal fibres, did not reveal a sex difference. Cluster analyses of spike activities indicated a massive and long-lasting activation of TRPM3 channels with preferential induction of large-amplitude spikes in female mice. Additional spectral analysis revealed ​a dominant contribution of spiking activity in the α- and β-ranges following TRPM3 agonists in female mice.

Conclusions

Together, we revealed a specific mechanosensitive profile of nociceptive firing in females and suggest TRPM3 channels as a potential novel candidate for the generation of migraine pain, with particular relevance to females.

Nutrients to Improve Mitochondrial Function to Reduce Brain Energy Deficit and Oxidative Stress in Migraine

The mechanisms of migraine pathogenesis are not completely clear, but ³¹P-nuclear magnetic resonance studies revealed brain energy deficit in migraineurs. As glycolysis is the main process of energy production in the brain, mitochondria may play an important role in migraine pathogenesis. Nutrition is an important aspect of migraine pathogenesis, as many migraineurs report food-related products as migraine triggers. Apart from approved anti-migraine drugs, many vitamins and supplements are considered in migraine prevention and therapy, but without strong supportive evidence. In this review, we summarize and update information about nutrients that may be important for mitochondrial functions, energy production, oxidative stress, and that are related to migraine. Additionally, we present a brief overview of caffeine and alcohol, as they are often reported to have ambiguous effects in migraineurs. The nutrients that can be considered to supplement the diet to prevent and/or ameliorate migraine are riboflavin, thiamine, magnesium ions, niacin, carnitine, coenzyme Q10, melatonin, lipoic acid, pyridoxine, folate, and cobalamin. They can supplement a normal, healthy diet, which should be adjusted to individual needs determined mainly by the physiological constitution of an organism. The intake of caffeine and alcohol should be fine-tuned to the history of their use, as withdrawal of these agents in regular users may become a migraine trigger.

The visual-ocular and vestibulo-ocular reflexes in vestibular migraine

Vestibular migraine is a disease from the border of neurology and otoneurology. The diagnosis depends on patient history. There are no valuable laboratory or imaging tests, therefore the examination of visual-ocular and vestibulo-ocular reflexes is very useful in this group of patients. The material was collected from patients diagnosed due to dizziness at the Department of Otolaryngology and Oncology with the Subdepartment of Audiology and Phoniatrics, CM UMK in Bydgoszcz in 2019–2021. We considered patients with vestibular migraine and analyzed videonystagmographic tests in this study. The most common VNG abnormalities in patients suffering from vestibular migraine were an increased labyrinthine response, increased time constant of the rotational response and abnormal optokinetic response. There was not a single case of canal paresis in the group of patients with vestibular migraine.