From current understanding of migraine pathophysiology, the investigators know that it involves excitability of the trigeminovascular system. Intercranial vasculature containing nociceptor innervation consists of unmyelinated (c-fibers) and thinly myelinated (a-delta fibers ) axons which hold vasoactive neuropeptides including substance P and (CGRP) calcitonin gene related peptide. When a migraine occurs, there is a cortical spreading depolarization, which on a molecular level involves a release of ATP, glutamate, potassium, hydrogen ions, glia or vascular cells, and CGRP and nitric oxide by activated perivascular nerves. These substances, including CGRP diffuse to come in contact with nociceptors causing neurogenic inflammation (vasodilation), thus propagating a headache.
Electrical perineural dry needling causes the release of substance-P and CGRG predominantly from non-neural structures, facilitating a negative feedback loop to neural and neuroactive components of the target tissue. This causes a lowering of the levels of CGRP which in turn decreases the inflammatory component thought to play a role in migraine headaches.
