|Ph.D Student||Avnon Yehoudith|
|Subject||The Parasympathetic System in Migraine|
|Department||Department of Medicine||Supervisor||Professor David Yarnitsky|
Aim: Evaluation of parasympathetic tone in migraine patients outside attacks.
Introduction: Migraine is often accompanied by autonomic parasympathetic symptoms such as exaggerated facial sweating, lacrimation, flushing and nasal congestion. Lidocaine intranasal instillation, which blocks most parasympathetic outflow to the cranium, is an effective migraine treatment. This implicates the parasympathetic system in migraine pathogenesis, which suggests that migraine patients might evidence altered parasympathetic tone. Method: 39 female migraineurs and 16 healthy women were evaluated. We evaluated the trigemino- parasympathetic reflex, which reflects cranial parasympathetic tone, in order to detect parasympathetically induced cutaneous vasodilatation in response to ocular irritation. Changes in cutaneous blood volume were measured by photo-plethysmography. Results: Migraine patients had different vascular responses compared to controls; Migraine patients suffering from bilateral head pain had an increased vasodilatation, while migraineurs with unilateral head pain had a lesser increase in vascular response compared to controls. Conclusion: Different migraine presentations are associated with different parasympathetic responses; Bilateral pain patients evidence increased parasympathetic activity, while those with unilateral migraine evidence decreased parasympathetic activity. These changes result from a dysfunctinal pain control system; absence of the normal reciprocal inhibitory relationships between the two locus cerulei may contribute to the augmented parasympathetic response in bilateral migraineurs, while an excess of reciprocal inhibitory relatiobships between the loci may contribute to the diminished parasympathetic response in unilateral migraineurs. These findings might help us understand migraine pathogenesis.