Amplification of glyceryl trinitrate-induced headache features by noxious craniofacial stimuli in pain-free healthy humans.

Aim: Glyceryl trinitrate (GTN) provokes an immediate migraine-like headache, followed by a delayed migraine attack in migraineurs. In healthy volunteers, only an immediate, less severe and shorter headache occurs. The presence of an already sensitized nervous system in migraineurs may underlie the more intense and prolonged GTN-evoked headaches. We tested if in healthy humans, application of noxious cutaneous and/or mechanical stimulation within craniofacial region would enhance or prolong GTN-evoked headache. Materials & methods: Noxious stimuli with a capsaicin patch on forehead, a mechanical headband, or both were applied prior to sublingual GTN (0.5 mg) in 20 healthy volunteers. GTN-induced headache characteristics and sensory responsiveness were recorded. Results: A more intense GTN-evoked headache was produced following application of headband. Conclusion: Noxious mechanical stimulation prior to GTN resulted in a more intense GTN-evoked headache.