Nav: Home

Migraine rats, medical facts

January 31, 2020

London, UK: Migraine mechanisms are still far from being fully understood. Escalating data from animal models are "fact-checking" the neurophysiological and behavioral correlates of the migraine experience in humans. A series of studies published in the journal Cephalalgia, the official journal of the International Headache Society, have described the underlying mechanisms and molecules related to migraine, and how they may be affected by current anti-migraine drugs or might translate into new therapies.

Evidence suggests that migraine can originate from either central or peripheral mechanisms. Central mechanisms mean that changes in structures of the central nervous system, such as the cortex, hypothalamus, thalamus, among others, are altered, modifying brain excitability, leading to headache attacks. One mechanism believed to cause migraine is cortical spreading depression (CSD). CSD is a depolarization wave of the neurons that spreads from the occipital cortex (neck region) to parietal cortex and is also related to the migraine aura. The peripheral mechanism, on the other hand, involves the activation of nociceptors (neurons that process painful stimuli) in the meninges that surround the brain and cerebral vessels. However, CSD (with central origin) can activate the trigeminovascular system, where the nociceptors of the meninges and brain vessels come from. In a series of recent studies, these animal models are shedding more light on migraine therapies and etiological mechanisms.

Onabotulinum toxin A

Onabotulinum toxin type A (Botox) has been shown to be effective in the treatment of chronic migraine. Studies carried out with lab animals simulating neurophysiological mechanisms of the disease, are beginning to reveal how these medications work against migraine.

A research group from the Beth Israel Deaconess Medical Center and Harvard Medical School, led by Dr. Rami Burstein, showed that the induction of CSD in rats, simulating a migraine attack, activates the trigeminovascular system and increases the triggering of nociceptors from the meninges. More recently, these same group of researchers showed that in female rats the application of Botox applied peripherally to the lambdoid and sagittal sutures reduced the nociceptor shots induced by CSD by 72%, indicating that the activation of nociceptors by central migraine-inducing phenomena, such as CSD, can be blocked by Botox.

CGRP

The calcitonin gene-related peptide (CGRP)) is an inflammatory and vasodilator neuropeptide that is elevated in the circulation of people with migraine and induces migraine in these patients when injected intravenously.

A growing number of studies in preclinical migraine models have shown that females are more susceptible to the nociceptive effects of CGRP, possibly due to estrogen amplifying effects on CGRP receptors. A Brazilian study, led by Dr. Juliana Geremias Chichorro, from the Federal University of Paraná, showed in another animal model of migraine that the CGRP applied within the trigeminal ganglion was able to induce neurophysiological and behavioral responses in male and female rats similar to migraine in humans, such as cutaneous allodynia (when the scalp/skin becomes painful to non-painful stimuli), intolerance to light (photophobia) and anxiety behavior. Interestingly, drugs with neuroprotective actions such as minocycline and propentophylline were effective in inhibiting the effects of CGRP only in male rats. However, sumatriptan, which is currently prescribed to abort migraine attacks, was effective in inhibiting the action of CGRP in both sexes.

PACAP-38

Lastly, but not least, a research from Dr. Lars Edvinsson's lab at the University of Lund, Sweden, found that in rats, another migraine-related emerging neuropeptide, namely, the pituitary adenylate cyclase-activating polypeptide (PACAP-38), co-localized with CGRP in areas of the brain that are related to the origin of migraine attacks. PACAP-38 and CGRP matched well in the cerebral cortex, cerebellum, thalamus, hypothalamus, the pons and spinal trigeminal nucleus, which are well-known neuroanatomic sites related to migraine.

These are a few examples of how pre-clinical studies go further into migraine mechanisms of symptoms and behaviors in humans, as well as provide insightful data on migraine therapies' mechanisms of action.
-end-


International Headache Society

Related Migraine Articles:

Disparities in migraine by sexual orientation
Survey data were used to examine the association between sexual orientation (exclusively heterosexual, mostly heterosexual, lesbian, gay or bisexual) and migraine.
Can you paint your migraine?
'Can you draw me a picture of your headache?' may sound like an unusual question - but drawings of headache pain provide plastic surgeons with valuable information on which patients are more or less likely to benefit from surgery to alleviate migraine headaches.
Acupuncture can reduce migraine headaches
Acupuncture can reduce migraine headaches compared to both sham (placebo) acupuncture and usual care, finds a new trial from China published by The BMJ today.
Migraine rats, medical facts
Migraine mechanisms are still far from being fully understood. Escalating data from animal models are 'fact-checking' the neurophysiological and behavioral correlates of the migraine experience in humans, and how they may be affected by current anti-migraine drugs or might translate into new therapies.
Connecting the dots in the migraine brain
This dMRI study pointed to the structural strengthening of connections involving subcortical regions associated with pain processing and weakening in connections involving cortical regions associated with hyperexcitability may coexist in migraine.
Predictors of chronic migraine
A review and meta-analysis found predictors of chronic migraine. Depression, high frequency attacks, medication overuse and allodynia increased the chances for new onset chronic migraine, while annual income -- US$ 50,000 showed a protective effect.
On nitroglycerin, cardiovascular homeostasis and...bam, migraine!
Researchers in Leiden, The Netherlands, found an exaggerated cardiovascular response to nitroglycerin infusion in migraine patients, suggesting an elevated systemic sensitivity to this compound in this population.
All roads lead to migraine
Dr. Samaira Younis, from the Danish Headache Center in Copenhagen, Denmark, shares her research results, which suggests there are no differences between migraine attacks clinical characteristics following administration of 2 different compounds in patients, CGRP and sildenafil, meaning they share common cellular signaling pathways.
Running away from exercise: The curious case of migraine
In spite of the widespread recommendation for regular physical activity as a strategy to manage migraine, for some patients, exercise can instead trigger migraine attacks.
Migraine prevention in children and adolescents
Two medicines already used to prevent migraine in adults also showed efficacy in adolescents with migraine.
More Migraine News and Migraine Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.