title: Vagus nerve stimulation inhibits cortical spreading depression.
abstract: Vagus nerve stimulation has recently been reported to improve symptoms of migraine. Cortical spreading depression is the electrophysiological event underlying migraine aura and is a trigger for headache. We tested whether vagus nerve stimulation inhibits cortical spreading depression to explain its antimigraine effect. Unilateral vagus nerve stimulation was delivered either noninvasively through the skin or directly by electrodes placed around the nerve. Systemic physiology was monitored throughout the study. Both noninvasive transcutaneous and invasive direct vagus nerve stimulations significantly suppressed spreading depression susceptibility in the occipital cortex in rats. The electrical stimulation threshold to evoke a spreading depression was elevated by more than 2-fold, the frequency of spreading depressions during continuous topical 1 M KCl was reduced by ∼40%, and propagation speed of spreading depression was reduced by ∼15%. This effect developed within 30 minutes after vagus nerve stimulation and persisted for more than 3 hours. Noninvasive transcutaneous vagus nerve stimulation was as efficacious as direct invasive vagus nerve stimulation, and the efficacy did not differ between the ipsilateral and contralateral hemispheres. Our findings provide a potential mechanism by which vagus nerve stimulation may be efficacious in migraine and suggest that susceptibility to spreading depression is a suitable platform to optimize its efficacy.
authors.affiliation: Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan Department of Neurology, Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA ElectroCore LLC, Basking Ridge, NJ, USA Stroke Service and Neuroscience Intensive Care Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
authors.forename: Shih-Pin
authors.initials: SP
authors.lastname: Chen
authors.forename: Ilknur
authors.initials: I
authors.lastname: Ay
authors.forename: Andreia
authors.initials: A
authors.lastname: Lopes de Morais
authors.forename: Tao
authors.initials: T
authors.lastname: Qin
authors.forename: Yi
authors.initials: Y
authors.lastname: Zheng
authors.forename: Homa
authors.initials: H
authors.lastname: Sadeghian
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Oka
authors.forename: Bruce
authors.initials: B
authors.lastname: Simon
authors.forename: Katharina
authors.initials: K
authors.lastname: Eikermann-Haerter
authors.forename: Cenk
authors.initials: C
authors.lastname: Ayata
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology; D013181:Cortical Spreading Depression / Q000502:physiology*; D004558:Electric Stimulation; D008297:Male; D008881:Migraine Disorders / Q000503:physiopathology*; D023421:Models, Animal; D017207:Rats, Sprague-Dawley; D055536:Vagus Nerve Stimulation