Muscle nerve sympathetic activity in migraine. Lack of abnormality

Microelectrode recordings of muscle nerve sympathetic activity (MSA) in the peroneal nerve were performed in eight patients with common migraine, when they were free of headache and during a spontaneously occurring attack of migraine. During the migraine headache all subjects remained on the same level of MSA as in the control situation and the responses to manoeuvres (slow deep breathing, the Valsalva manoeuvre, sustained hand grip, immersion of one hand into ice water) showed no qualitative or quantitative change. Assessment of vagal influence on the heart showed no change from control situation to attack of migraine. The study provides direct evidence against the existence of any abnormality of MSA during ongoing migraine headache and does not support the assumption that migraine is a generalized vasomotor disorder. No conclusions about possible dysfunction in other parts of the sympathetic nervous system can be drawn.