Advanced brain MRI may help understand the link between migraine and multiple sclerosis.

BACKGROUND: There is a clinical association between migraine and multiple sclerosis. MAIN BODY: Migraine and MS patients share similar demographics, with the highest incidence among young, female and otherwise healthy patients. The same hormonal constellations/changes trigger disease exacerbation in both entities. Migraine prevalence is increased in MS patients, which is further enhanced by disease-modifying treatment. Clinical data show that onset of migraine typically starts years before the clinical diagnosis of MS, suggesting that there is either a unidirectional relationship with migraine predisposing to MS, and/or a "shared factor" underlying both conditions. Brain imaging studies show white matter lesions in both MS and migraine patients. Neuroinflammatory mechanisms likely play a key role, at least as a shared downstream pathway. In this review article, we provide an overview of the literature about 1) the clinical association between migraine and MS as well as 2) brain MRI studies that help us better understand the mechanistic relationship between both diseases with implications on their underlying pathophysiology. CONCLUSION: Studies suggest a migraine history predisposes patients to develop MS. Advanced brain MR imaging may shed light on shared and distinct features, while helping us better understand mechanisms underlying both disease entities.

CADASIL mutations sensitize the brain to ischemia via spreading depolarizations and abnormal extracellular potassium homeostasis.

Cerebral autosomal dominant arteriopathy, subcortical infarcts, and leukoencephalopathy (CADASIL) is the most common monogenic form of small vessel disease characterized by migraine with aura, leukoaraiosis, strokes, and dementia. CADASIL mutations cause cerebrovascular dysfunction in both animal models and humans. Here, we showed that 2 different human CADASIL mutations (Notch3 R90C or R169C) worsen ischemic stroke outcomes in transgenic mice; this was explained by the higher blood flow threshold to maintain tissue viability compared with that in wild type (WT) mice. Both mutants developed larger infarcts and worse neurological deficits compared with WT mice, regardless of age or sex after filament middle cerebral artery occlusion. However, full-field laser speckle flowmetry during distal middle cerebral artery occlusion showed comparable perfusion deficits in mutants and their respective WT controls. Circle of Willis anatomy and pial collateralization also did not differ among the genotypes. In contrast, mutants had a higher cerebral blood flow threshold, below which infarction ensued, suggesting increased sensitivity of brain tissue to ischemia. Electrophysiological recordings revealed a 1.5- to 2-fold higher frequency of peri-infarct spreading depolarizations in CADASIL mutants. Higher extracellular K+ elevations during spreading depolarizations in the mutants implicated a defect in extracellular K+ clearance. Altogether, these data reveal a mechanism of enhanced vulnerability to ischemic injury linked to abnormal extracellular ion homeostasis and susceptibility to ischemic depolarizations in CADASIL.

Cutaneous Findings of Sporadic, Adult-Onset Neuronal Intranuclear Inclusion Disease.

ABSTRACT: Neuronal intranuclear inclusion disease is a rare, progressive neurodegenerative disease whose hallmark histopathologic finding is the presence of ubiquitin-positive hyaline intranuclear inclusions in neuronal and non-neuronal cells. We present a case of neuronal intranuclear inclusion disease in a 61-year-old Asian man with a history of repeated episodes of altered mental status, long-standing bladder dysfunction, and cerebrovascular accidents. The patient had characteristic magnetic imaging findings of high signal along the cortico-medullary junction on diffusion-weighted sequences and symmetric T2 hyperintensity in the paravermal area of the cerebellum. Skin biopsies showed characteristic histopathologic findings of ubiquitin-positive intranuclear inclusions that ultrastructurally composed of filamentous material without limiting membrane within eccrine epithelium and dermal fibroblasts. Our case highlights the utility of readily accessible skin biopsy in the diagnosis of this rare neurodegenerative disease.

Neuronal plumes initiate spreading depolarization, the electrophysiologic event driving migraine and stroke.

In this issue of Neuron, Parker et al. discover neuronal plumes of glutamate release that initiate spreading depolarization, the electrophysiologic event underlying migraine. Mice with human migraine mutations express spontaneous and frequent plumes, which may explain the propensity to develop migraine attacks and the increased stroke risk in migraine-susceptible brains.

Structural and Functional Brain Changes in Migraine.

Migraine is a prevalent primary headache disorder and is usually considered as benign. However, structural and functional changes in the brain of individuals with migraine have been reported. High frequency of white matter abnormalities, silent infarct-like lesions, and volumetric changes in both gray and white matter in individuals with migraine compared to controls have been demonstrated. Functional magnetic resonance imaging (MRI) studies found altered connectivity in both the interictal and ictal phase of migraine. MR spectroscopy and positron emission tomography studies suggest abnormal energy metabolism and mitochondrial dysfunction, as well as other metabolic changes in individuals with migraine. In this review, we provide a brief overview of neuroimaging studies that have helped us to characterize some of these changes and discuss their limitations, including small sample sizes and poorly defined control groups. A better understanding of alterations in the brains of patients with migraine could help not only in the diagnosis but may potentially lead to the optimization of a targeted anti-migraine therapy.

White Matter Lesions in Migraine.

Migraine, the third most common disease worldwide, is a well-known independent risk factor for subclinical focal deep white matter lesions (WMLs), even in young and otherwise healthy individuals with no cardiovascular risk factors. These WMLs are more commonly seen in migraine patients with transient neurologic symptoms preceding their headaches, the so-called aura, and those with a high attack frequency. The pathophysiology of migraine-related deep white matter hyperintensities remains poorly understood despite their prevalence. Characteristic differences in their distribution compared with those of common periventricular WMLs in the elderly suggest a different underlying mechanism. Both ischemic and inflammatory mechanisms have been proposed, as there is increased cerebral vulnerability to ischemia in migraineurs, whereas there is also evidence of blood-brain barrier disruption with associated release of proinflammatory substances during migraine attacks. An enhanced susceptibility to spreading depolarization, the electrophysiological event underlying migraine, may be the mechanism that causes repetitive episodes of cerebral hypoperfusion and neuroinflammation during migraine attacks. WMLs can negatively affect both physical and cognitive function, underscoring the public health importance of migraine, and suggesting that migraine is an important contributor to neurologic deficits in the general population.

Acute sleep deprivation enhances susceptibility to the migraine substrate cortical spreading depolarization.

BACKGROUND: Migraine is a common headache disorder, with cortical spreading depolarization (CSD) considered as the underlying electrophysiological event. CSD is a slowly propagating wave of neuronal and glial depolarization. Sleep disorders are well known risk factors for migraine chronification, and changes in wake-sleep pattern such as sleep deprivation are common migraine triggers. The underlying mechanisms are unknown. As a step towards developing an animal model to study this, we test whether sleep deprivation, a modifiable migraine trigger, enhances CSD susceptibility in rodent models. METHODS: Acute sleep deprivation was achieved using the "gentle handling method", chosen to minimize stress and avoid confounding bias. Sleep deprivation was started with onset of light (diurnal lighting conditions), and assessment of CSD was performed at the end of a 6 h or 12 h sleep deprivation period. The effect of chronic sleep deprivation on CSD was assessed 6 weeks or 12 weeks after lesioning of the hypothalamic ventrolateral preoptic nucleus. All experiments were done in a blinded fashion with respect to sleep status. During 60 min of continuous topical KCl application, we assessed the total number of CSDs, the direct current shift amplitude and duration of the first CSD, the average and cumulative duration of all CSDs, propagation speed, and electrical CSD threshold. RESULTS: Acute sleep deprivation of 6 h (n = 17) or 12 h (n = 11) duration significantly increased CSD frequency compared to controls (17 ± 4 and 18 ± 2, respectively, vs. 14 ± 2 CSDs/hour in controls; p = 0.003 for both), whereas other electrophysiological properties of CSD were unchanged. Acute total sleep deprivation over 12 h but not over 6 h reduced the electrical threshold of CSD compared to controls (p = 0.037 and p = 0.095, respectively). Chronic partial sleep deprivation in contrast did not affect CSD susceptibility in rats. CONCLUSIONS: Acute but not chronic sleep deprivation enhances CSD susceptibility in rodents, possibly underlying its negative impact as a migraine trigger and exacerbating factor. Our findings underscore the importance of CSD as a therapeutic target in migraine and suggest that headache management should identify and treat associated sleep disorders.

How Imaging Can Help Us Better Understand the Migraine-Stroke Connection.

Migraine and stroke are among the most prevalent and disabling neurological diseases. Epidemiologic studies showed that there is an association between migraine and stroke. Migraineurs, especially those with aura, are more likely to develop subclinical infarct-like lesions in the brain and are at risk for cryptogenic or cardioembolic stroke. Migrainous headache can be found at the onset of acute ischemic stroke in some patients, and in rare instances, an infarction can be directly attributed to a prolonged migraine aura, ie, migrainous infarction. Importantly, recent studies suggest that in the event of cerebral artery occlusion, even a history of migraine is sufficient to accelerate infarct progression and worsen outcomes. The mechanisms underlying the migraine-stroke connection are multifactorial, with genetic predisposition, aura-related electrophysiological mechanisms (cortical spreading depolarization), and cerebral microembolism being the most convincing ones at this point. Here, we provide a comprehensive overview on recent imaging studies that have helped us better understand the complex association between migraine and stroke.

No Gastrointestinal Dysmotility in Transgenic Mouse Models of Migraine.

OBJECTIVE: To determine whether transgenic mouse models of migraine exhibit upper gastrointestinal dysmotility comparable to those observed in migraine patients. BACKGROUND: There is considerable evidence supporting the comorbidity of gastrointestinal dysmotility and migraine. Gastrointestinal motility, however, has never been investigated in transgenic mouse models of migraine. METHODS: Three transgenic mouse strains that express pathogenic gene mutations linked to monogenic migraine-relevant phenotypes were studied: CADASIL (Notch3-Tg88), FASP (CSNK1D-T44A), and FHM1 (CACNA1A-S218L). Upper gastrointestinal motility was quantified by measuring gastric emptying and small intestinal transit in mutant and control animals. Gastrointestinal motility was measured at baseline and after pretreatment with 10 mg/kg nitroglycerin (NTG). RESULTS: No significant differences were observed for gastric emptying or small intestinal transit at baseline for any of the 3 transgenic strains when compared to appropriate controls or after pretreatment with NTG when compared to vehicle. CONCLUSIONS: We detected no evidence of upper gastrointestinal dysmotility in mice that express mutations in genes linked to monogenic migraine-relevant phenotypes. Future studies seeking to understand why humans with migraine experience delayed gastric emptying may benefit from pursuing other modifiers of gastrointestinal motility, such as epigenetic or microbiome-related factors.

Relief Following Chronic Stress Augments Spreading Depolarization Susceptibility in Familial Hemiplegic Migraine Mice.

Cortical spreading depolarization (CSD) is the electrophysiological substrate of migraine aura, and a putative trigger of trigeminovascular activation and migraine headache. Many migraineurs report stress or relief after a stress triggers an attack. We tested whether various stress conditions might modulate CSD susceptibility and whether this is dependent on genetic factors. Male and female wild type and familial hemiplegic migraine type1 (FHM1) knock-in mice heterozygous for the S218L missense mutation were subjected to acute or chronic stress, or chronic stress followed by relief (36 h). Acute stress was induced by restraint and exposure to bright light and white noise (3 h). Chronic stress was induced for 28 days by two cycles of repeated exposure of mice to a rat (7 days), physical restraint (3 days), and forced swimming (3 days). Electrical CSD threshold and KCl-induced (300 mM) CSD frequency were determined in occipital cortex in vivo at the end of each protocol. Relief after chronic stress reduced the electrical CSD threshold and increased the frequency of KCl-induced CSDs in FHM1 mutants only. Acute or chronic stress without relief did not affect CSD susceptibility in either strain. Stress status did not affect CSD propagation speed, duration or amplitude. In summary, relief after chronic stress, but not acute or chronic stress alone, augments CSD in genetically susceptible mice. Therefore, enhanced CSD susceptibility may explain why, in certain patients, migraine attacks typically occur during a period of stress relief such as weekends or holidays.

Aura and Stroke: relationship and what we have learnt from preclinical models.

BACKGROUND: Population-based studies have highlighted a close relationship between migraine and stroke. Migraine, especially with aura, is a risk factor for both ischemic and hemorrhagic stroke. Interestingly, stroke risk is highest for migraineurs who are young and otherwise healthy. MAIN BODY: Preclinical models have provided us with possible mechanisms to explain the increased vulnerability of migraineurs' brains towards ischemia and suggest a key role for enhanced cerebral excitability and increased incidence of microembolic events. Spreading depolarization (SD), a slowly propagating wave of neuronal depolarization, is the electrophysiologic event underlying migraine aura and a known headache trigger. Increased SD susceptibility has been demonstrated in migraine animal models, including transgenic mice carrying human mutations for the migraine-associated syndrome CADASIL and familial hemiplegic migraine (type 1 and 2). Upon experimentally induced SD, these mice develop aura-like neurological symptoms, akin to patients with the respective mutations. Migraine mutant mice also exhibit an increased frequency of ischemia-triggered SDs upon experimental stroke, associated with accelerated infarct growth and worse outcomes. The severe stroke phenotype can be explained by SD-related downstream events that exacerbate the metabolic mismatch, including pericyte contraction and neuroglial inflammation. Pharmacological suppression of the genetically enhanced SD susceptibility normalizes the stroke phenotype in familial hemiplegic migraine mutant mice. Recent epidemiologic and imaging studies suggest that these preclinical findings can be extrapolated to migraine patients. Migraine patients are at risk for particularly cardioembolic stroke. At the same time, studies suggest an increased incidence of coagulopathy, atrial fibrillation and patent foramen ovale among migraineurs, providing a possible path for microembolic induction of SD and, in rare instances, stroke in hyperexcitable brains. Indeed, recent imaging studies document an accelerated infarct progression with only little potentially salvageable brain tissue in acute stroke patients with a migraine history, suggesting an increased vulnerability towards cerebral ischemia. CONCLUSION: Preclinical models suggest a key role for enhanced SD susceptibility and microembolization to explain both the occurrence of migraine attacks and the increased stroke risk in migraineurs. Therapeutic targeting of SD and microembolic events, or potential causes thereof, will be promising for treatment of aura and may also prevent ischemic infarction in vulnerable brains.

Current understanding of cortical structure and function in migraine.

OBJECTIVE: To review and discuss the literature on the role of cortical structure and function in migraine. DISCUSSION: Structural and functional findings suggest that changes in cortical morphology and function contribute to migraine susceptibility by modulating dynamic interactions across cortical and subcortical networks. The involvement of the cortex in migraine is well established for the aura phase with the underlying phenomenon of cortical spreading depolarization, while increasing evidence suggests an important role for the cortex in perception of head pain and associated sensations. As part of trigeminovascular pain and sensory processing networks, cortical dysfunction is likely to also affect initiation of attacks. CONCLUSION: Morphological and functional changes identified across cortical regions are likely to contribute to initiation, cyclic recurrence and chronification of migraine. Future studies are needed to address underlying mechanisms, including interactions between cortical and subcortical regions and effects of internal (e.g. genetics, gender) and external (e.g. sensory inputs, stress) modifying factors, as well as possible clinical and therapeutic implications.

Caffeine does not affect susceptibility to cortical spreading depolarization in mice.

Several factors that modulate migraine, a common primary headache disorder, also affect susceptibility to cortical spreading depolarization (CSD). CSD is a wave of neuronal and glial depolarization and thought to underlie the migraine aura and possibly headache. Here, we tested whether caffeine, known to alleviate or trigger headache after acute exposure or chronic use/withdrawal, respectively, modulates CSD. We injected C57BL/6J mice with caffeine (30, 60, or 120 mg/kg; i.p.) once ( acute) or twice per day for one or two weeks ( chronic). Susceptibility to CSD was evaluated by measuring the electrical CSD threshold and by assessing KCl-induced CSD. Simultaneous laser Doppler flowmetry was used to assess CSD-induced cortical blood flow changes. Recordings were performed 15 min after caffeine/vehicle administration, or 24 h after the last dose of chronic caffeine in the withdrawal group. The latter paradigm was also tested in mice carrying the familial hemiplegic migraine type 1 R192Q missense mutation, considered a valid migraine model. Neither acute/chronic administration nor withdrawal of caffeine affected CSD susceptibility or related cortical blood flow changes, either in WT or R192Q mice. Hence, adverse or beneficial effects of caffeine on headache seem unrelated to CSD pathophysiology, consistent with the non-migrainous clinical presentation of caffeine-related headache.

The association between migraine and hospital readmission due to pain after surgery: A hospital registry study.

BACKGROUND: Migraine has been identified as a risk factor of 30-day hospital readmission after surgery. We aimed to further characterize this association examining pain as a potentially migraine-associated, preventable reason for readmission. HYPOTHESIS: Compared to patients with no migraine, surgical patients with migraine are at increased risk of 30-day hospital readmission with an admitting diagnosis specifying pain. METHODS: This hospital registry study examined 150,710 patients aged 18 years and above, who underwent surgery with general anesthesia and mechanical ventilation between 2007 and 2015 at a tertiary care center and two affiliated community hospitals in Massachusetts, USA. RESULTS: Migraine was associated with an increased risk of 30-day pain-related readmission after surgery (adjusted odds ratio 1.42 [95% confidence interval 1.15-1.75]). The association was stronger for migraine with aura (compared to migraine without aura: Adjusted odds ratio 1.69 [95% confidence interval 1.06-2.70]; compared to no migraine: Adjusted odds ratio 2.20 [95% confidence interval 1.44-3.37]). The predicted adjusted risk of pain-related 30-day readmissions was 9.1 [95% confidence interval 5.3-13.0] in 1000 surgical patients with migraine with aura and 5.4 [95% confidence interval 4.2-6.6] in 1000 patients with migraine without aura, compared to 4.2 [95% confidence interval 3.8-4.5] in 1000 patients with no migraine. Furthermore, migraine was associated with an increased risk of postsurgical 30-day readmission due to a priori defined migraine-related pain (headache or abdominal pain) (adjusted odds ratio 1.55 [95% confidence interval 1.20-2.00]). CONCLUSION: Patients with migraine undergoing surgery are at increased risk of 30-day hospital readmission due to pain.

Sex and Gender Differences in Migraine-Evaluating Knowledge Gaps.

Migraine is a common chronic neurological disease that disproportionately affects women. Migraine has significant negative effects on physical, emotional, and social aspects of health, and can be costly for patients, employers, and society as a whole. Growing evidence supports the roles of sex and gender in migraine risk, pathophysiology, presentation, diagnosis, treatment, and management. However, sex and gender differences in migraine have received limited attention, which can impede advancements in migraine detection, treatment, care, and education. The Society for Women's Health Research convened an interdisciplinary expert panel of researchers, clinicians, and advocates for a roundtable meeting to review the current research on sex and gender differences in migraine. This review summarizes discussions from the roundtable and prioritizes areas of need that warrant further attention in migraine research, care, and education. Examining sex and gender differences in migraine and addressing knowledge gaps will decrease the health and economic burden of migraine for both women and men.

Hereditary multiple exostoses as a novel cause of bilateral popliteal artery aneurysms in the elderly.

Hereditary multiple exostoses (HME) is a genetic condition characterized by the development of multiple osteochondromas during childhood and adolescence. On rare occasions, these bony tumors can be associated with vascular injury, most commonly involving the popliteal artery. Such patients typically present with vascular complications in adolescence and young adulthood. We report an autopsy study of an elderly man who presented with bilateral popliteal artery pseudoaneurysms in the setting of HME at age 81. This is the oldest patient presenting with a vascular complication due to HME reported to date, as well as the only known case of bilateral popliteal pseudoaneurysms caused by HME. This is also the only autopsy study of this vascular complication so far reported. Our case illustrates that vascular complications from HME can occur even in the elderly, and may show bilateral involvement.

Inhibition of the P2X7-PANX1 complex suppresses spreading depolarization and neuroinflammation.

Spreading depolarization is a wave of neuronal and glial depolarization. Within minutes after spreading depolarization, the neuronal hemichannel pannexin 1 (PANX1) opens and forms a pore complex with the ligand-gated cation channel P2X7, allowing the release of excitatory neurotransmitters to sustain spreading depolarization and activate neuroinflammation. Here, we explore the hypothesis that the P2X7-PANX1 pore complex is a critical determinant of spreading depolarization susceptibility with important consequences for neuroinflammation and trigeminovascular activation. We found that genetic loss of function or ablation of the P2x7 gene inhibits spreading depolarization. Moreover, pharmacological suppression of the P2X7-PANX1 pore complex inhibits spreading depolarization in mice carrying the human familial hemiplegic migraine type 1 R192Q missense mutation as well as in wild-type mice and rats. Pore inhibitors elevate the electrical threshold for spreading depolarization, and reduce spreading depolarization frequency and amplitude. Pore inhibitors also suppress downstream consequences of spreading depolarization such as upregulation of interleukin-1 beta, inducible nitric oxide synthase and cyclooxygenase-2 in the cortex after spreading depolarization. In addition, they inhibit surrogates for trigeminovascular activation, including expression of calcitonin gene-related peptide in the trigeminal ganglion and c-Fos in the trigeminal nucleus caudalis. Our results are consistent with the hypothesis that the P2X7-PANX1 pore complex is a critical determinant of spreading depolarization susceptibility and its downstream consequences, of potential relevance to its signature disorders such as migraine.

Migraine and risk of perioperative ischemic stroke and hospital readmission: hospital based registry study.

OBJECTIVE:  To evaluate whether patients with migraine are at increased risk of perioperative ischemic stroke and whether this may lead to an increased hospital readmission rate. DESIGN:  Prospective hospital registry study. SETTING:  Massachusetts General Hospital and two satellite campuses between January 2007 and August 2014. PARTICIPANTS:  124 558 surgical patients (mean age 52.6 years; 54.5% women). MAIN OUTCOME MEASURES:  The primary outcome was perioperative ischemic stroke occurring within 30 days after surgery in patients with and without migraine and migraine aura. The secondary outcome was hospital readmission within 30 days of surgery. Exploratory outcomes included post-discharge stroke and strata of neuroanatomical stroke location. RESULTS:  10 179 (8.2%) patients had any migraine diagnosis, of whom 1278 (12.6%) had migraine with aura and 8901 (87.4%) had migraine without aura. 771 (0.6%) perioperative ischemic strokes occurred within 30 days of surgery. Patients with migraine were at increased risk of perioperative ischemic stroke (adjusted odds ratio 1.75, 95% confidence interval 1.39 to 2.21) compared with patients without migraine. The risk was higher in patients with migraine with aura (adjusted odds ratio 2.61, 1.59 to 4.29) than in those with migraine without aura (1.62, 1.26 to 2.09). The predicted absolute risk is 2.4 (2.1 to 2.8) perioperative ischemic strokes for every 1000 surgical patients. This increases to 4.3 (3.2 to 5.3) for every 1000 patients with any migraine diagnosis, 3.9 (2.9 to 5.0) for migraine without aura, and 6.3 (3.2 to 9.5) for migraine with aura. : Patients with migraine had a higher rate of readmission to hospital within 30 days of discharge (adjusted odds ratio 1.31, 1.22 to 1.41). CONCLUSIONS:  Surgical patients with a history of migraine are at increased risk of perioperative ischemic stroke and have an increased 30 day hospital readmission rate. Migraine should be considered in the risk assessment for perioperative ischemic stroke.

A Novel Strategy to Reverse General Anesthesia by Scavenging with the Acyclic Cucurbit[n]uril-type Molecular Container Calabadion 2.

BACKGROUND: Calabadion 2 is a new drug-encapsulating agent. In this study, the authors aim to assess its utility as an agent to reverse general anesthesia with etomidate and ketamine and facilitate recovery. METHODS: To evaluate the effect of calabadion 2 on anesthesia recovery, the authors studied the response of rats to calabadion 2 after continuous and bolus intravenous etomidate or ketamine and bolus intramuscular ketamine administration. The authors measured electroencephalographic predictors of depth of anesthesia (burst suppression ratio and total electroencephalographic power), functional mobility impairment, blood pressure, and toxicity. RESULTS: Calabadion 2 dose-dependently reverses the effects of ketamine and etomidate on electroencephalographic predictors of depth of anesthesia, as well as drug-induced hypotension, and shortens the time to recovery of righting reflex and functional mobility. Calabadion 2 displayed low cytotoxicity in MTS-3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium-based cell viability and adenylate kinase release cell necrosis assays, did not inhibit the human ether-à-go-go-related channel, and was not mutagenic (Ames test). On the basis of maximum tolerable dose and acceleration of righting reflex recovery, the authors calculated the therapeutic index of calabadion 2 in recovery as 16:1 (95% CI, 10 to 26:1) for the reversal of ketamine and 3:1 (95% CI, 2 to 5:1) for the reversal of etomidate. CONCLUSIONS: Calabadion 2 reverses etomidate and ketamine anesthesia in rats by chemical encapsulation at nontoxic concentrations.

Animal models of monogenic migraine.

Migraine is a highly prevalent and disabling neurological disorder with a strong genetic component. Rare monogenic forms of migraine, or syndromes in which migraine frequently occurs, help scientists to unravel pathogenetic mechanisms of migraine and its comorbidities. Transgenic mouse models for rare monogenic mutations causing familial hemiplegic migraine (FHM), cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and familial advanced sleep-phase syndrome (FASPS), have been created. Here, we review the current state of research using these mutant mice. We also discuss how currently available experimental approaches, including epigenetic studies, biomolecular analysis and optogenetic technologies, can be used for characterization of migraine genes to further unravel the functional and molecular pathways involved in migraine.