Central 5-HT receptor hypersensitivity in migraine without aura

Prolactin and oxytocin: potential targets for migraine treatment

Migraine is a severe neurovascular disorder of which the pathophysiology is not yet fully understood. Besides the role of inflammatory mediators that interact with the trigeminovascular system, cyclic fluctuations in sex steroid hormones are involved in the sex dimorphism of migraine attacks. In addition, the pituitary-derived hormone prolactin and the hypothalamic neuropeptide oxytocin have been reported to play a modulating role in migraine and contribute to its sex-dependent differences. The current narrative review explores the relationship between these two hormones and the pathophysiology of migraine. We describe the physiological role of prolactin and oxytocin, its relationship to migraine and pain, and potential therapies targeting these hormones or their receptors.In summary, oxytocin and prolactin are involved in nociception in opposite ways. Both operate at peripheral and central levels, however, prolactin has a pronociceptive effect, while oxytocin appears to have an antinociceptive effect. Therefore, migraine treatment targeting prolactin should aim to block its effects using prolactin receptor antagonists or monoclonal antibodies specifically acting at migraine-pain related structures. This action should be local in order to avoid a decrease in prolactin levels throughout the body and associated adverse effects. In contrast, treatment targeting oxytocin should enhance its signalling and antinociceptive effects, for example using intranasal administration of oxytocin, or possibly other oxytocin receptor agonists. Interestingly, the prolactin receptor and oxytocin receptor are co-localized with estrogen receptors as well as calcitonin gene-related peptide and its receptor, providing a positive perspective on the possibilities for an adequate pharmacological treatment of these nociceptive pathways. Nevertheless, many questions remain to be answered. More particularly, there is insufficient data on the role of sex hormones in men and the correct dosing according to sex differences, hormonal changes and comorbidities. The above remains a major challenge for future development.

A link between gastrointestinal disorders and migraine: Insights into the gut-brain connection

Background

Migraine is a complex, multifaceted, and disabling headache disease that is often complicated by gastrointestinal (GI) conditions, such as gastroparesis, functional dyspepsia, and cyclic vomiting syndrome (CVS). Functional dyspepsia and CVS are part of a spectrum of disorders newly classified as disorders of gut–brain interaction (DGBI). Gastroparesis and functional dyspepsia are both associated with delayed gastric emptying, while nausea and vomiting are prominent in CVS, which are also symptoms that commonly occur with migraine attacks. Furthermore, these gastric disorders are comorbidities frequently reported by patients with migraine. While very few studies assessing GI disorders in patients with migraine have been performed, they do demonstrate a physiological link between these conditions.

Objective

To summarize the available studies supporting a link between GI comorbidities and migraine, including historical and current scientific evidence, as well as provide evidence that symptoms of GI disorders are also observed outside of migraine attacks during the interictal period. Additionally, the importance of route of administration and formulation of migraine therapies for patients with GI symptoms will be discussed.

Methods

A literature search of PubMed for articles relating to the relationship between the gut and the brain with no restriction on the publication year was performed. Studies providing scientific support for associations of gastroparesis, functional dyspepsia, and CVS with migraine and the impact these associations may have on migraine treatment were the primary focus. This is a narrative review of identified studies.

Results

Although the association between migraine and GI disorders has received very little attention in the literature, the existing evidence suggests that they may share a common etiology. In particular, the relationship between migraine, gastric motility, and vomiting has important clinical implications in the treatment of migraine, as delayed gastric emptying and vomiting may affect oral dosing compliance, and thus, the absorption and efficacy of oral migraine treatments.

Conclusions

There is evidence of a link between migraine and GI comorbidities, including those under the DGBI classification. Many patients do not find adequate relief with oral migraine therapies, which further necessitates increased recognition of GI disorders in patients with migraine by the headache community.

An Association of Serotonin with Pain Disorders and Its Modulation by Estrogens

Ovarian hormones play an important role in pain perception, and are responsible, at least in part, for the pain threshold differences between the sexes. Modulation of pain and its perception are mediated by neurochemical changes in several pathways, affecting both the central and peripheral nervous systems. One of the most studied neurotransmitters related to pain disorders is serotonin. Estrogen can modify serotonin synthesis and metabolism, promoting a general increase in its tonic effects. Studies evaluating the relationship between serotonin and disorders such as irritable bowel syndrome, fibromyalgia, migraine, and other types of headache suggest a clear impact of this neurotransmitter, thereby increasing the interest in serotonin as a possible future therapeutic target. This literature review describes the importance of substances such as serotonin and ovarian hormones in pain perception and illustrates the relationship between those two, and their direct influence on the presentation of the aforementioned pain-related conditions. Additionally, we review the pathways and receptors implicated in each disorder. Finally, the objective was to stimulate future pharmacological research to experimentally evaluate the potential of serotonin modulators and ovarian hormones as therapeutic agents to regulate pain in specific subpopulations.

Evidence for hyperprolactinemia in migraineurs: a systematic review and meta-analysis

BACKGROUND

One of the hypothalamus-pituitary axis hormones which may play a crucial role in pathophysiology of migraine is prolactin which is secreted from anterior pituitary gland and synthesized by various immune system cells as well. Whether prolactin blood levels can affect the migraine pathogenesis is an open question. Therefore, investigating prolactin circulatory levels in migraineurs may pave the way to underpin the mechanisms of migraine pathophysiology at biochemical levels. In the current investigation, the prolactin blood levels in the migraine subjects were investigated using systematic review and meta-analysis.

METHODS

Using online and specialized biomedical databases including Google Scholar, Medline, Pubmed, Pubmed Central, Embase, and Scopus, without the beginning date restriction until Feb 2019, the systematic review retrieved 11 publications in this systematic review after fulfilling for the inclusion and exclusion criteria. For heterogeneity, extent calculation statistical testing was applied. In the present study, the levels of circulatory prolactin in migraineurs assessed using standardized mean difference (SMD) as the effect size.

RESULTS

Q quantity and I²% statistic index showed a high heterogeneity in the 13 selected publications (188.370 and 92.568, respectively) and random-effects model was chosen for further analyses. The meta-analysis on a total number of 460 migraineurs and 429 healthy controls found that the weighted pooled SMD for the effects of prolactin blood concentrations on migraine pathogenesis was as follows: SMD = 1.435 (95% confidence interval, 0.854-2.015).

CONCLUSION

The current investigation presents evidence that prolactin blood levels are higher in migraineurs than healthy subjects.

Prevalence and pathophysiology of post-prandial migraine in patients with functional dyspepsia

Background

Migraine is a condition frequently associated with gastrointestinal disorders. Previous reports have shown the relationship between irritable bowel syndrome and migraine, but no data are yet available in patients with functional dyspepsia. We therefore evaluated whether alteration of gastric sensorimotor activity may be related to migraine.

Methods

Sixty patients affected by functional dyspepsia, 38 with postprandial distress syndrome and 22 with epigastric pain syndrome were enrolled in a cohort study. Presence and severity of dyspeptic symptoms, migraine presence and severity, gastric sensitivity thresholds during fasting and postprandial period, gastric accommodation and gastric emptying time were evaluated.

Results

In epigastric pain syndrome, 12/22 (54%) patients suffered from migraine and this condition was never correlated with meal ingestion. In postprandial distress syndrome patients, 29/38 (76%) suffered from migraine, in 26/29 (89%) its onset was considered as meal-related, and migraine severity was significantly correlated with postprandial modification of the gastric discomfort threshold (r = −0.73; p < 0.001). In patients with postprandial distress syndrome, in the subgroup with moderate to severe migraine, the severity of fullness and early satiation was significantly higher than in patients with mild or absent migraine. In patients with moderate to severe migraine, gastric accommodation, sensitivity thresholds and gastric emptying time were similar to patients with mild or no migraine.

Conclusions

In patients with functional dyspepsia and postprandial symptoms, migraine is a very frequent comorbidity. On clinical grounds, it is associated with an increased severity of fullness and early satiation and, on pathophysiological grounds, it seems correlated with postprandial hypersensitivity.

Prophylactic effects of asiaticoside-based standardized extract of Centella asiatica (L.) Urban leaves on experimental migraine: Involvement of 5HT1A/1B receptors

The present study aimed at evaluation of prophylactic efficacy and possible mechanisms of asiaticoside (AS) based standardized extract of Centella asiatica (L.) Urban leaves (INDCA) in animal models of migraine. The effects of oral and intranasal (i.n.) pretreatment of INDCA (acute and 7-days subacute) were evaluated against nitroglycerine (NTG, 10 mg·kg(-1), i.p.) and bradykinin (BK, 10 μg, intra-arterial) induced hyperalgesia in rats. Tail flick latencies (from 0 to 240 min) post-NTG treatment and the number of vocalizations post-BK treatment were recorded as a measure of hyperalgesia. Separate groups of rats for negative (Normal) and positive (sumatriptan, 42 mg·kg(-1), s.c.) controls were included. The interaction of INDCA with selective 5-HT1A, 5-HT1B, and 5-HT1D receptor antagonists (NAN-190, Isamoltane hemifumarate, and BRL-15572 respectively) against NTG-induced hyperalgesia was also evaluated. Acute and sub-acute pre-treatment of INDCA [10 and 30 mg·kg(-1) (oral) and 100 μg/rat (i.n.) showed significant anti-nociception activity, and reversal of the NTG-induced hyperalgesia and brain 5-HT concentration decline. Oral pre-treatment with INDCA (30 mg·kg(-1), 7 d) showed significant reduction in the number of vocalization. The anti-nociceptive effects of INDCA were blocked by 5-HT1A and 5-HT1B but not 5-HT1D receptor antagonists. In conclusion, INDCA demonstrated promising anti-nociceptive effects in animal models of migraine, probably through 5-HT1A/1B medicated action.

Comparing treatments for endometriosis-related pain symptoms in patients with migraine without aura

Endometriosis is a gynecological disorder defined by the presence of endometrial-like tissue outside the uterus. Several studies have found an epidemiological correlation between endometriosis and migraine, probably due to the association of both diseases with female hormones. Progestins or combined oral contraceptives are the first-line medical therapy in women with endometriosis; however, it is well known that in some women the use of combined oral contraceptives could exacerbate migraine. This observation poses a challenge to clinicians who must concomitantly treat endometriosis-related symptoms and migraine. This review summarizes the available literature on the medical treatment of endometriosis in women suffering concomitant migraine without aura until March 2012. Due to the lack of available studies on this topic, it is difficult to draw definitive conclusions. Further studies evaluating hormonal therapies are needed; in particular, progestin therapy should be reconsidered in women with migraine and concomitant endometriosis.

Period prevalence of self-reported headache in the general population in Germany from 1995-2005 and 2009: results from annual nationwide population-based cross-sectional surveys

BACKGROUND

Although primary headache is the most frequent neurological disorder and there is some evidence that the prevalence rates have increased in recent years, no long-term data on the annual prevalence of headache are available for Germany. The objective of the study was therefore to obtain long-term data on the period prevalence of headache in the general population in Germany by means of population-based cross-sectional annual surveys (1995-2005 and 2009).

METHODS

These surveys were conducted as face-to-face paper-and-pencil interviews from 1995 through 2004, and from 2005 onwards as computer-aided personal interviews. The reported headaches were self-diagnosed by the interviewees. Per year, approximately 640 trained interviewers interviewed between 10,898 and 12,538 German-speaking individuals aged 14 and older and living in private households in the whole of Germany (response rate: 67.4% and 73.1%, gross samples: 16,026 to 18,176 subjects). A total of more than 146,000 face-to-face interviews were analyzed.

RESULTS

The one-year headache prevalence remained stable over the entry period, with 58.9% (95%CI 57.7-60.1) to 62.5% (95%CI 61.3-63.7) (p=0.07). Women showed consistently higher prevalence rates than men (females: 67.3 (95%CI 65.7-68.9) to 70.7% (95%CI 69.1-72.3), males: 48.4% (95%CI 46.5-50.3) to 54.3% (95%CI 52.4-56.2)), and both sexes showed a bell-shaped age dependence with peaks in the 30-39 age group. A stable slightly higher prevalence was observed in urban versus rural areas (p<0.0001), and there was also a significant trend towards higher prevalence rates in groups with a monthly household income larger than 3,500 € (p=0.03).

CONCLUSION

The overall headache prevalence remained stable in Germany in the last 15 years.

Headache in essential thrombocythaemia

Headache is frequently reported as one of the neurological manifestations of essential thrombocythaemia (ET) and other myeloproliferative neoplasms. It is associated with considerable morbidity; yet, it is a frequently under-recognised symptom. In patients with ET, headaches may be attributable to the disease, to the prescribed ET treatment, or unrelated to ET. The majority of headaches in ET are self-limiting and can be managed with standard headache therapies such as paracetamol, but it is vital that the clinician managing these conditions is able to recognise the headaches with a more sinister pathology. In this article, we will review the incidence and management of headaches in ET, whether they are primarily related to the disease or a result of its treatment. Identification of specific headache types in patients with ET may enable physicians to employ the most effective headache medication. This would enhance the patient-physician relationship, increasing patient compliance and thus reducing the risk of adverse outcomes.

Brainstem changes in 5-HT1A receptor availability during migraine attack

BACKGROUND

Among serotonin receptors, 5-HT(1A) receptors are implicated in the regulation of central serotoninergic tone and could be involved in the abnormal brain 5-HT turnover suspected in migraineurs. The aim of this study was to investigate 5-HT(1A) receptors' availability during migraine attacks.

METHODS

Ten patients suffering from odor-triggered migraine attacks and 10 control subjects were investigated using positron emission tomography (PET) and [(18)F]MPPF PET tracer, a selective 5-HT(1A) antagonist. All subjects underwent calibrated olfactory stimulations prior to the PET study.

RESULTS

Four patients developed a migraine attack during the PET study. In these patients, statistical parametrical mapping and region of interest analyses showed an increased [(18)F]MPPF binding potential (BP(ND)) in the pontine raphe when compared to headache-free migraineurs and control subjects. This ictal change was confirmed at the individual level in each of the four affected patients. In comparison with the headache-free migraineurs, patients with a migraine attack also showed significantly increased [(18)F]MPPF BP(ND) in the left orbitofrontal cortex, precentral gyrus and temporal pole. No significant change in [(18)F]MPPF BP(ND) was observed between headache-free migraineurs and controls.

CONCLUSIONS

Our results emphasize the role of 5HT(1A) receptors in the pontine raphe nuclei during the early stage of migraine attacks.

Managing Migraines: Options for Acute Abortive Treatment

Introduction

Triptans, ergotamine derivatives and nonsteroidal anti-inflammatory drugs are front-line agents used in the acute abortive therapy of migraines. In this article, these medications are reviewed and a treatment algorithm suggested.

Methods

A comprehensive review of the literature from 1990 to 2008 was conducted using PubMed, MEDLINE and The Cochrane Library to explore the underlying pathophysiology of migraines and comparatively assess the acute and chronic treatment options available in their management. The information obtained from all literature searches was further categorized as level 1, 2 or 3 based on pre-defined peer-reviewed criteria.

Conclusion:

This review is able to present a relatively preliminary but practical migraine treatment algorithm. Although there is no standard universal treatment strategy to manage migraine headaches in all patients, this review has been put forth to serve as a clinical guideline to assist health professionals in deciding the most appropriate treatment for migraine headaches.

Interictal brain 5-HT1A receptors binding in migraine without aura: a 18F-MPPF-PET study

In this study we aimed to assess the brain distribution of 5-HT(1A) receptors in migraine patients without aura. Ten female migraine patients and 24 female healthy volunteers underwent magnetic resonance imaging and positron emission tomography using a radioligand antagonist of 5-HT(1A) receptors [4-(2'-methoxyphenyl)-1-[2'-(N-2-pirydynyl)-p-fluorobenzamido]-ethylpiperazine ((18)F-MPPF)]. A simplified reference tissue model was used to generate parametric images of 5-HT(1A) receptor binding potential (BP) values. Statistical Parametrical Mapping (SPM) analysis showed increased MPPF BP in posterior cortical areas and hippocampi bilaterally in patients compared with controls. Region of interest (ROI) analysis showed a non-significant trend in favour of a BP increase patients in cortical regions identified by the SPM analysis except in hippocampi, left parietal areas and raphe nuclei. During the interictal period of migraine patients without aura, the increase of MPPF BP in posterior cortical and limbic areas could reflect an increase in receptor density or a decrease of endogenous serotonin, which could explain their altered cortical excitability.

Current and prospective pharmacological targets in relation to antimigraine action

Migraine is a recurrent incapacitating neurovascular disorder characterized by unilateral and throbbing headaches associated with photophobia, phonophobia, nausea, and vomiting. Current specific drugs used in the acute treatment of migraine interact with vascular receptors, a fact that has raised concerns about their cardiovascular safety. In the past, alpha-adrenoceptor agonists (ergotamine, dihydroergotamine, isometheptene) were used. The last two decades have witnessed the advent of 5-HT(1B/1D) receptor agonists (sumatriptan and second-generation triptans), which have a well-established efficacy in the acute treatment of migraine. Moreover, current prophylactic treatments of migraine include 5-HT(2) receptor antagonists, Ca(2+) channel blockers, and beta-adrenoceptor antagonists. Despite the progress in migraine research and in view of its complex etiology, this disease still remains underdiagnosed, and available therapies are underused. In this review, we have discussed pharmacological targets in migraine, with special emphasis on compounds acting on 5-HT (5-HT(1-7)), adrenergic (alpha(1), alpha(2,) and beta), calcitonin gene-related peptide (CGRP(1) and CGRP(2)), adenosine (A(1), A(2), and A(3)), glutamate (NMDA, AMPA, kainate, and metabotropic), dopamine, endothelin, and female hormone (estrogen and progesterone) receptors. In addition, we have considered some other targets, including gamma-aminobutyric acid, angiotensin, bradykinin, histamine, and ionotropic receptors, in relation to antimigraine therapy. Finally, the cardiovascular safety of current and prospective antimigraine therapies is touched upon.

Recognition and treatment of menstrual migraine

BACKGROUND

Menstrual migraine is a chronic disorder affecting approximately 12.6 million women in the United States. In spite of its widespread prevalence, menstrual migraine often goes undiagnosed.

REVIEW SUMMARY

Characteristics of menstrual migraine, which include functional disability, increased headache severity, and lack of aura, are often overlooked, and therefore menstrual migraine is often underdiagnosed. Use of a 3-month diary to record migraine patterns can reveal the predictable patterns associated with menstrual migraine, and a diary is demonstrated to be a useful tool in diagnosis. Optimal treatment of menstrual migraine takes advantage of the predictability of the disorder. Treatment alternatives for menstrual migraine include acute therapy and short- or long-term preventive therapies. Acute therapy is given shortly after the migraine begins. Short-term preventive therapies are effective when administered during the time that menstrual migraine is most likely to occur; the treatment window is typically 2 days prior up to 3 days after the onset of menstruation. Providing triptans, nonsteroidal anti-inflammatory drugs, or estrogen supplements (gel or patches) during this window has been demonstrated to provide effective protection during the days when patients are at greatest risk for menstrual migraine. Alternatively, long-term preventive therapy may be required for recurrent headaches in patients with concomitant medical conditions for whom migraine therapy could serve a dual purpose.

CONCLUSION

By recognizing the patterns associated with menstrual migraine, prompt, acute, or preventive therapy can be used to effectively manage the disorder and reduce its related disability.

Family-based analysis of serotonin transporter gene polymorphisms in migraine with and without aura

Genetic epidemiological twin studies have demonstrated a significant heritability for migraine, with > 60% of liability to migraine either with or without aura coming from additive genetic factors. Because of the essential role of serotonin in the pathophysiology and treatment of migraine, genes of the serotonin system are candidates for involvement in migraine. Consequently, we examined two functional VNTR polymorphisms in the serotonin transporter gene, the 5-HTTLPR and the intron 2 VNTR, in a sample of 212 family trios each with a proband with childhood migraine, 153 with migraine without aura (MoA) and 59 with migraine with aura (MA). For the first time, we used transmission disequilibrium test analysis with the program TDTPHASE to examine the transmission of these two markers and their haplotypes to offspring affected by migraine. We found no significant transmission distortion of any marker, with the common L allele of the 5-HTTLPR transmitted 170 times and not transmitted 178 times, and the S allele 130 vs. 122 times. Likewise, the common 12 allele of the intron 2 VNTR was transmitted 201 times and not transmitted 188 times, and the 10 allele 107 vs. 120 times. The markers were not associated with MoA and MA and none of the haplotypes was associated with overall migraine, MoA or MA. The 5-HTTLPR and the intron 2 VNTRs do not play a major role in susceptibility to migraine.

Anger, depression and personality dimensions in patients with migraine without aura

BACKGROUND

Migraine without aura causes acute and chronic pain and partially compromises patients' social functioning and work performance. Over the past years, psychiatric comorbidities were frequently observed in these patients, together with coping difficulties and typical personality traits. The aim of this study was to identify whether migraine patients and controls share distinctive personality traits.

METHODS

105 consecutive patients suffering from migraine without aura referred to the Headache Center of Turin University were enrolled in the study and compared to a control group of 79 healthy subjects. Patients and controls completed several psychometric questionnaires, including the Temperament and Character Inventory, the Beck Depression Inventory and the State-Trait Anger Expression Inventory.

RESULTS

Patients suffering from migraine show more depressive symptoms, difficult anger management with a tendency to hypercontrol, and a distinctive personality profile with high harm avoidance, high persistence and low self-directedness. When a logistic regression was performed, the only significant predictors of migraine were temperament variables.

CONCLUSIONS

The results suggest that the personality traits and psychosomatic mechanisms of migraine patients may make them vulnerable to stress and less skilled in coping with pain. These traits correlate with dysregulated neurotransmitter systems which may also be part of the psychobiological components of personality, depressive disorders and migraine itself.

No association of C-1019G promoter polymorphism of 5-HT1A receptor gene with migraine

It is well known that migraine has a strong genetic component, although the type and number of genes involved remains unclear. There is evidence to suggest that serotonin-related genes may be involved in the pathogenesis of migraine. To investigate whether the 5-HT1A receptor gene contributes to the risk of migraine we performed an association study of C-1019G promoter polymorphism of the gene in 102 migraineurs and 93 controls. Subjects were of Han Chinese origin. No significant differences in allele (P=0.82) or genotype frequencies (P=0.71) were seen in migraineurs compared with the controls. When migraine with aura, without aura, with family history, without family history were analyzed separately, the frequencies did not vary significantly. Our results suggest that C-1019G in 5-HT1A is not a major genetic risk factor for migraine.

Ovarian Hormones and Migraine Headache: Understanding Mechanisms and Pathogenesis-Part 2

Migraine headache is strongly influenced by reproductive events that occur throughout the lifespan of women. Each of these reproductive events has a different "hormonal milieu," which might modulate the clinical course of migraine headache. Estrogen and progesterone can be preventative or provocative for migraine headache under different circumstances depending on their absolute serum levels, constancy of exposure, and types of estrogen/progesterone derivatives. Attacks of migraine with and without aura respond differently to changes in ovarian hormones. Clearly a greater knowledge of ovarian hormones and their effect on migraine is essential to a greater understanding of the mechanisms and pathogenesis of migraine headache.

Efficacy of the 5-HT1A agonist, buspirone hydrochloride, in migraineurs with anxiety: a randomized, prospective, parallel group, double-blind, placebo-controlled study

OBJECTIVE

To examine the efficacy of buspirone, a 5-HT1A agonist, for migraine combined with anxiety disorder.

BACKGROUND

Modulation of the 5-hydroxytryptamine (5-HT) system is used for the neuropharmacology of migraine treatment; however, the involvement of the 5-HT1A system in migraine is not fully understood.

METHODS

Seventy-four outpatients aged 20 to 70 years (mean, 46.4; SD, 12.8) were analyzed. All subjects were diagnosed to have migraine according to the International Headache Society criteria and anxiety disorder according to DSM-IV. Subjects were randomly assigned to treatment with either buspirone (10 mg/day) or placebo for 6 weeks. Efficacy variables included changes in headache frequency, headache intensity, Hamilton Anxiety Rating Scale (HAM-A), Headache Self-Efficacy Scale (HMSE), and Headache Disability Inventory (HDI). The correlation between the headache improvement and the anxiolytic effect was analyzed.

RESULTS

Headache frequency showed a 43.3% reduction in the buspirone-treated group, but by only 10.3% in the placebo group. HAM-A and HDI were also significantly more lowered in buspirone-treated patients than in placebo-treated patients. However, headache intensity and HMSE score were unchanged. Correlation analysis of the relation between headache frequency reduction and HAM-A improvement, revealed no significant association.

CONCLUSIONS

In this study, buspirone showed a prophylactic effect in migraine with anxiety disorder, which was not secondary to its anxiolytic effect. This suggests that the agonistic action for 5-HT1A can be directly effective in migraine prophylaxis. However, more long-term study is warranted before concluding the efficacy.