Migraine and ovarian steroid hormones

Relationship between Precipitating Agents and Neurophysiological Abnormalities in Migraine

The particular mechanisms of migraine anticipation by different precipitating agents are still unknown. The contingent negative variation (CNV) was recorded in the premenstrual and ovulation phases of the cycle in both rest and stress conditions in 17 migraine and 15 healthy women. In migraineurs a significant increase of amplitude of the initial CNV component in the premenstrual phase compared with ovulation was observed. During both the ovulation and premenstrual phases both migraineurs and controls demonstrated a significant increase of the CNV amplitude on stress. The increase of the amplitude on stress in the premenstrual phase was more pronounced in migraineurs. This study shows that stress and menstrual cycle are associated with changes of the initial CNV amplitude, probably indicating a higher probability of migraine attacks.

The pathophysiological and pharmacological basis of current drug treatment of migraine headache

Migraine is a common neurological syndrome that affects approximately 10-20% of the population. The pathophysiology of migraine is unclear. 5-hydroxytriptamine is a key mediator in the pathogenesis of migraine and thus 5-HT1-receptor agonists are the principal drugs for acute migraine therapy. There are three classes of drugs for migraine: over-the-counter analgesics and nonsteroidal anti-inflammatory drugs for acute mild migraine, specific prescription drugs (triptans and ergot alkaloids) for acute severe migraine and pharmacological agents for prophylaxis of migraine. Sumatriptan, naratriptan and others, referred to as 'triptans', are the mainstay for acute treatment of migraine. Ergot alkaloids (ergotamine, dihydroergotamine) are used in patients with frequent, moderate migraine, but are less effective than triptans. There are several agents for prevention of migraine occurrence in patients with frequent or severe disabling migraine attacks. New drugs with improved efficacy and reduced side effects are needed for effective treatment and prevention of migraine.

Sex differences in serotonin enhancement of capsaicin-evoked calcitonin gene-related peptide release from human dental pulp

Serotonin (5HT) is a pronociceptive mediator in the periphery, and evidence implicates involvement in trigeminal pain processing. However, the mechanism(s) by which 5HT modulates trigeminal nociceptors remains unclear. Trigeminal pain can be evoked by the transient receptor potential V1 channel (TRPV1), which is expressed by nociceptive trigeminal neurons and induces release of proinflammatory calcitonin gene-related peptide (CGRP). In our preclinical models, 5HT evoked thermal hyperalgesia and enhanced calcium influx and CGRP release from the TRPV1 population of trigeminal nociceptors. Whether this occurs in humans is unknown. As dental pulp is densely innervated by trigeminal nociceptors, routine tooth extractions offer a unique opportunity to examine whether 5HT enhances CGRP release from human nociceptors. Pulpal tissue was collected from 140 extracted molar teeth from men and women, and basal release samples were collected before treatment with saline or 5HT 100μmol/L. CGRP release was then stimulated with the TRPV1 agonist capsaicin 1μmol/L and quantitated by enzyme immunoassay. Additional samples were collected for Western blots to examine 5HT receptor expression. We report that 5HT induced a significant increase in capsaicin-evoked CGRP release, and that this enhancement was observed only in female dental pulp, with no effect of 5HT on male dental pulp. The greatest amount of CGRP release occurred in dental pulp from women in the luteal phase of the menstrual cycle. These results indicate that 5HT enhances capsaicin-evoked CGRP release from human trigeminal nociceptors in a sexually dimorphic manner providing a mechanistic basis for prevalence of trigeminal pain disorders in women.

The effect of estrogen and progesterone on spreading depression in rat neocortical tissues

Although gender differences in the incidence of migraine with aura appear to be related to high circulating levels of ovarian hormones, the underlying mechanisms are not yet fully understood. Several studies have suggested a major role for spreading depression (SD) in the pathogenesis and symptomatology of migraine with aura. To investigate a possible role of SD in the association of high female hormones and attacks of migraine with aura, the effects of beta-estradiol and progesterone on SD were studied in rat neocortical tissues. Application of both hormones enhanced the repetition rate as well as the amplitude of SD in neocortical slices treated with hypotonic artificial cerebrospinal fluid. beta-Estradiol and progesterone also dose dependently increased the amplitude of SD induced by KCl microinjection. Both hormones exhibited a pronounced, persisting, and significant enhancement of long-term potentiation of the field excitatory postsynaptic potential in the neocortical tissues. The changes in SD characteristics in the presence of estrogen and progesterone may responsible for increased migraine with aura attacks associated by high female hormones. These hormones may exert their effects on SD via facilitation of synaptic transmission.

Serotonin in Trigeminal Ganglia of Female Rodents: Relevance to Menstrual Migraine

OBJECTIVES

We examined changes in the serotonin system across the estrous cycle in trigeminal ganglia of female rodents to determine which components are present and which are regulated by the variations in levels of ovarian steroids that occur during the estrous cycle.

BACKGROUND

Migraine is 2-3 times more prevalent in women than in men and attacks are often timed with the menstrual cycle, suggesting a mechanistic link with ovarian steroids. Serotonin has been implicated in the pathogenesis of migraine, and the effectiveness of triptans, selective 5HT-1B/D/F agonists, has provided further support for this concept. It is not known whether serotonin, its rate-limiting enzyme tryptophan hydroxylase (TPH), or its receptors are regulated by ovarian steroids in trigeminal ganglia.

METHODS

We used reverse transcription-polymerase chain reaction to examine gene expression in cycling mice, Western blots to examine protein expression, double-labeling immunohistochemistry using markers of nociceptors and nonnociceptors and confocal microscopy to identify specific types of neurons, and primary tissue culture to examine effects of estrogen on trigeminal neurons in vitro.

RESULTS

In C57/BL6 mice mRNA levels of TPH-1, the rate-limiting enzyme in serotonin synthesis, were over 2-fold higher and protein levels were 1.4-fold higher at proestrus, the high estrogen stage of the cycle than at diestrus, the low estrogen stage. TPH protein also was present in primary trigeminal cultures obtained from female Sprague-Dawley rats, but levels were not affected by 24-hour treatment with physiological levels (10(-9) M) of 17beta-estradiol. Gene expression of 5HT-1B and 5HT-1D receptors in trigeminal ganglia was not regulated by the estrous cycle. Serotonin was present in trigeminal neurons containing CGRP, a potent vasoactive neuropeptide, peripherin, an intermediate filament present in neurons with unmyelinated axons, neurofilament H, which is present in neurons with myelinated axons, and in neurons binding IB4, a marker of nonpeptidergic nociceptors. Serotonin was also present in neurons containing 5HT-1B. The serotonin-positive population was significantly larger in diameter than the serotonin-negative population. Conclusions.-Expression of the rate-limiting enzyme required for serotonin synthesis is regulated during the natural estrous cycle, and serotonin is present in larger trigeminal neurons of all the major subtypes. Colocalization of serotonin with 5HT-1B suggests that this receptor functions as an autoreceptor to regulate serotonin release. Cyclical changes in serotonin levels in trigeminal ganglia could contribute to the pathogenesis of menstrual migraine.

Effects of oestrogen on trigeminal ganglia in culture: implications for hormonal effects on migraine

Although migraine is more common in women than men and often linked to the menstrual cycle, few studies have investigated the biological basis of hormonal influences on the trigeminovascular system. In the present study we investigated the effect of physiological levels (10(-9) m) oestrogen on female rat trigeminal ganglia in vitro. Immunocytochemical analysis demonstrated the presence of oestrogen receptor-alpha in a predominantly cytoplasmic location and in neurites. Microarray analysis demonstrated that oestrogen treatment regulates several genes with potential relevance to menstrual migraine. The genes that were upregulated included synapsin-2, endothelin receptor type B, activity and neurotransmitter-induced early gene 7 (ania-7), phosphoserine aminotransferase, MHC-1b, and ERK-1. Down-regulated genes included IL-R1, bradykinin B2 receptor, N-tropomodulin, CCL20, GABA transporter protein, fetal intestinal lactase-phlorizin hydrolase, carcinoembryonic antigen-related protein, zinc finger protein 36, epsin 1 and cysteine string protein. Protein activity assays demonstrated that exposure of the cultured neurons to oestrogen leads to activation of ERK, which has been linked to inflammatory pain. Immunocytochemistry demonstrated that activated ERK was present in neurons containing peripherin, a marker of nociceptive neurons. Several of the genes in the present study may provide potential targets for understanding the association of oestrogen with migraine and other hormone-related orofacial pain.

Role of the needling per se in acupuncture as prophylaxis for menstrually related migraine: a randomized placebo-controlled study

The objectives were to introduce a new method for controlled trials of acupuncture in the field of headache research and to examine the role of needling per se. Women with menstrually related migraine were randomized to three months of treatment with verum or placebo needles. Three standard size casts were moulded to secure the placebo needles in the head. No significant differences were found between the verum group (n=15) and the placebo group (n=13) during treatment or follow up three and six months later, either in the attack frequency or in the number of days per month with migraine, headache intensity or drug-use. The casts held the needles exactly in place despite movements of the head, and are validated as practical, hygienic and extremely durable. This method is satisfactory for controlled studies of acupuncture in headache. It is possible that the positive results in earlier clinical trials on acupuncture in migraine are attributable to other mechanisms than needling of subcutaneous tissue.

Premenstrual syndromes: closing the 20th century chapters

The need to re-evaluate premenstrual syndromes became apparent in 1997-1998 and early 1999. The success stories of some symptomatic treatment modalities and more sophisticated studies of pathobiology chart the pathways for future progress: the shift from a descriptive diagnosis to diagnoses based on etiology, the recognition of diversified vulnerabilities and their expression in particular situations, and specific treatment modalities.

Sumatriptan is effective in the treatment of menstrual migraine: a review of prospective studies and retrospective analyses

Menstrual migraine may be debilitating, long-lasting, and refractory to treatment. Because the efficacy and tolerability of abortive and prophylactic treatment options for menstrual migraine have generally not been evaluated in controlled clinical trials, treatment choices are often made on the basis of personal experience and anecdotal reports. This article reviews evidence from retrospective analyses and prospective studies showing that sumatriptan injection and tablets are effective and well tolerated in menstrual migraine. (1) Sumatriptan injection 6 mg was as effective in the treatment of menstrual migraine attacks as it was for nonmenstrual attacks in a retrospective analysis of data from two randomized, double-blind, placebo-controlled, parallel-group trials (n = 1104). In the menstrual migraine group, 80% of women treated with sumatriptan injection 6 mg compared with 19% of placebo-treated patients reported headache relief 1 h postdose (p < 0.001). (2) Sumatriptan injection 6 mg was effective in the acute treatment of menstrual migraine attacks in a prospective, double-blind, placebo-controlled, parallel-group, two-attack study (n = 226). Across the two attacks, 70-71% of patients treating menstrual migraine attacks with sumatriptan injection 6 mg compared with 22-24% of placebo-treated patients reported headache relief 1 h postdose (p < 0.001). (3) Sumatriptan tablets 100 mg were effective in the acute treatment of menstrual migraine attacks in a prospective, double-blind, placebo-controlled, crossover study in women diagnosed with menstrual migraine (n = 115). For menstrual migraine attacks, headache relief 4 h postdose was reported by 67% of sumatriptan-treated patients compared with 33% of placebo-treated patients. Sumatriptan injection and tablets were generally well tolerated in these studies, in which adverse events were characteristic of those typically observed in sumatriptan acute migraine clinical trials. These data demonstrate that sumatriptan injection and tablets are effective and well tolerated in the treatment of menstrual migraine.