Oxygen Inhibits Neuronal Activation in the Trigeminocervical Complex After Stimulation of Trigeminal Autonomic Reflex, But Not During Direct Dural Activation of Trigeminal Afferents

The data provide the first systematic, experimental evidence for a mechanism of action of oxygen in cluster headache. The data show oxygen has no direct effect on trigeminal afferents, acting specifically on the parasympathetic/facial nerve projections to the cranial vasculature to inhibit both evoked trigeminovascular activation and activation of the autonomic pathway during cluster headache attacks. Moreover, the studies begin to characterize a novel laboratory model for the most painful primary headache syndrome known--cluster headache.