Cortical spreading depression reduces dural blood flow--a possible mechanism for migraine pain?

These experiments were designed to investigate a possible mechanism linking the phenomenon of cortical spreading depression with activation of the trigeminal sensory system in migraine. Blood flow in the cortex and middle meningeal artery was measured in cats before and during propagation of a wave of cortical spreading depression, initiated by cortical pin-prick. This caused a transient propagated increase in cortical blood flow. Cortical spreading depression was accompanied by a decrease in blood flow in the middle meningeal artery, sometimes to very low levels. The results suggest that the pain of migraine could arise from dural ischemia induced by cortical spreading depression.