A team of researchers from the University of Texas at Dallas (TX, USA) have determined that CGRP exhibits pain effects in a sex-specific manner. The paper, published in the Journal of Neuroscience, may help us understand why women are more likely to experience migraines than men.
For several decades CGRP has been known to play a prominent role in migraines. However, preclinical research into this role has often only involved male animals. “This leaves the question of neurobiological sex differences unanswered,” commented Greg Dussor (University of Texas at Dallas).
It has also not yet been determined where in the body CGRP acts to contribute to migraines. “CGRP is produced both in the CNS – the brain and spinal cord – and in the PNS, which goes everywhere else, including the meninges. But it can’t move between the two; it’s too large to cross the blood–brain barrier that shields the CNS,” explained Dussor.
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This study analyzed the effects of injecting CGRP into the outer layer of the meninges of both male and female rodents. Only the female animals exhibited symptoms of headache pain. “This is the first study to show that CGRP might act differently between sexes,” stated Dussor. “It also shows that CGRP can have a pain-related effect in the meninges, which is something that has been questioned in the literature previously.”
As the male rodents were unaffected by the injection of CGRP into the meninges, Dussor suggested that: “CGRP-based signaling from the meninges may contribute to the female-biased nature of this disorder.”
The team also determined that the female animals experienced a similar pain response when the CGRP when it was injected at other sites of the body such as the paws. “That response shows that females may be more sensitive to CGRP throughout the body, not just the meninges,” continued Dussor.
There is still much work to be done in determining how CGRP acts differently in males and females. “Although CGRP plays a clear role in migraine, this does not imply that migraine is exclusively a CGRP-based disorder,” concluded Dussor. “This is just the beginning of demonstrations showing that CGRP might act differently in women.”
Source: EurekAlert. Migraine-linked protein exhibits sex-specific pain effects. Press release: www.eurekalert.org