Stimulation of the superior sagittal sinus in the cat causes release of vasoactive peptides

External jugular vein blood was sampled in the anesthetized cat during electrical stimulation of the superior sagittal sinus (SSS), and the levels of calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), substance P (SP) and neuropeptide Y (NPY) were measured with sensitive radioimmunoassays. CGRP levels rose by 85% and VIP levels by 300% while there was no change in SP or NPY levels in the same samples. These data provide the first evidence that activation of the trigeminovascular system, by selective stimulation of nociceptive craniovascular afferents, causes releases of vasodilator peptides and further implicates this system in the pathophysiology of migraine.