Migraine II

My last migraine episode reminded me in no uncertain terms about the gastro-intestinal aspects of the condition. The complete lack of cold symptoms at the time also made me doubt my previous ideas about a viral origin (though I still think it was an interesting idea!). This has led me to a re-think, and a realisation that the emetic centres of the brain ( specifically the area postrema in the medulla) must have some involvement. This links to some extent to the observations from PET scans (as reported by the Migraine Trust) that brain stem areas appear to be active during migraine attacks. The Migraine Trust article indicates that current thinking is more in favour of neurological origins of migraine than vascular, but I wonder if both are involved. The area postrema is a curious structure that by-passes the blood-brain barrier to some extent and is sensitive to several circulating chemicals. One substance for which receptiors have been found is prolactin, which apparently is associated with osmoregulation in lower animals. Perhaps migraine attacks are associated with changes in prolactin levels - these can vary diurnally and seasonally, and perhaps might peak after periods of stress; the osmoregulatory aspect of its function may cause changes in intra-cranial pressure associated with headache.The involvement of prolactin - or something like it - might also help explain why females are more affected than males, and why women tend to suffer less after menopause (see Migraine Trust factsheet). However, migraine does not seem to be a major symptom of hyperprolactinaemia. Apparently, dopamine tends to inhibit synthesis of prolactin, so the ultimate orgin of migraines may be disturbances to dopaminergic pathways - this could be tested by appropriate use of dopamine agaonists/antagonists.
It's another idea, anyway!