Nobody is aware of why CSD begins; equally, a lot stays a thriller about what triggers the ache of a migraine. Earlier analysis has proposed that migraines are brought about when one thing within the cerebrospinal fluid not directly prompts nerves within the close by meninges, the membrane layer between the mind and the cranium. Rasmussen’s experiments, led by neuroscientist Maiken Nedergaard, initially aimed to search out proof to assist this, however got here up with nothing. “We acquired nothing,” he says.
So the researchers tried a distinct method: they injected a fluorescent tracer substance into the cerebrospinal fluid and imaged the skulls of mice. The tracer concentrated on the finish of the trigeminal nerve, “there are two massive bundles of nerves on the base of the cranium, like a sausage.” It was a giant shock to search out that the substance might attain this a part of the peripheral nervous system and activate ache receptors, he says. “So we have been excited and on the similar time very puzzled: how does it get there?” This led the researchers to a gap on the finish of the trigeminal nerve that comes into contact with the cerebrospinal fluid.
The researchers additionally took samples of cerebrospinal fluid and located greater than 100 proteins that have been elevated or decreased after CSD, suggesting they could play a job in migraine ache. Twelve of the elevated proteins are recognized to behave as transmitters that may activate sensory nerves, together with one referred to as calcitonin gene-related peptide (CGRP), a recognized goal for migraine medication. Discovering CGRP within the combination was a superb signal, Rasmussen says. “However what’s most attention-grabbing to us are the opposite 11 proteins that have not been described earlier than,” he says, as a result of they may open the door to new remedies.
Turgay Darukara, a professor of neurology at Turkey’s Hacettepe College who has an curiosity in auras, says there are nonetheless causes to be cautious. Rodent and human skulls are problematic“The floor area-to-volume ratio is dramatically completely different between mice and people,” Rasmussen says. The concept CSD releases substances that activate and sensitize nerves within the meninges, which Rasmussen’s crew first investigated, stays the best-supported mechanism noticed in people, he provides. Rasmussen’s discovery of this beforehand undiscovered location the place cerebrospinal fluid can contact nerves provides to this image, not replaces it.
Hajikani agrees, however remains to be excited to search out additional avenues of investigation. For docs, the lack of information about how migraines work means trying to find the correct mixture of medicines that may carry sufferers some aid. “Attempt one. Attempt a mix. Drop one,” she says. “It’s a must to be Sherlock Holmes to search out out what’s inflicting it.”
As a result of migraines range broadly, there might not be a one-size-fits-all answer, however Rasmussen hopes that in the long run, modifications in a person’s cerebrospinal fluid might assist decrease among the guesswork and supply tailor-made options.
