Event-related slow potentials and associated catecholamine function in migraine.

Plasma norepinephrine and dopamine and event-related slow potentials were measured at menses and ovulation in migraine with and without aura relative to normal subjects. The results indicated that at menses, but not ovulation, plasma dopamine was increased and norepinephrine was decreased relative to normal. This catecholamine imbalance was greater in migraine without aura than in migraine with aura. Conversely, event-related slow potentials measured over the posterior cortex at ovulation but not at the menses was altered relative to normal. Early epoch negativity was reduced in migraine with aura, whereas late epoch negativity was reduced in migraine without aura. The results suggested that (a) migraine without aura may involve dynamic shifts in the function of both norepinephrine and dopamine responsive neurons; (b) pathophysiology of migraine with aura is less dependent on catecholamine imbalance (norepinephrine alone affected); (c) these pathophysiological mechanisms are most prevalent in or restricted to posterior cortical regions but may be modulated by brainstem mechanisms.