Papers of the Week

Motion-induced anxiety and agoraphobia are more frequent symptoms in patients with vestibular migraine than migraine without vertigo. The neuropeptide calcitonin gene-related peptide (CGRP) is a therapeutic target for migraine and vestibular migraine, but the link between motion hypersensitivity, anxiety, and CGRP is relatively unexplored, especially in preclinical mouse models. To further examine this link, we tested the effects of systemic CGRP and off-vertical axis rotation (OVAR) on elevated plus maze (EPM) and rotarod performance in male and female C57BL/6J mice. Rotarod ability was assessed using two different dowel diameters: mouse dowel (r = 1.5 cm) versus rat dowel (r = 3.5 cm). EPM results indicate that CGRP alone or OVAR alone did not increase anxiety indexes. However, the combination of CGRP and OVAR did elicit anxiety-like behavior. On the rotarod, CGRP reduced performance in both sexes on a mouse dowel but had no effect on a rat dowel, whereas OVAR had a significant effect on the rat dowel. These results suggest that only the combination of CGRP with vestibular stimulation induce anxiety-like behavior; and that CGRP affects dynamic balance function in mice depending on the type of challenge presented. These findings suggest that anxiety-like behaviors can be teased out from imbalance behaviors in a mouse model of “migraine”. Future studies are aimed to determine if CGRP receptor antagonists that have been effective treating migraineurs and mouse “migraine” models may also reduce the anxiety observed in migraine. Anxiety is very common in patients with dizziness and migraine. Elevated CGRP levels have been linked to migraine symptoms of increased light and touch sensitivity in mice and humans and we wondered if a systemic injection of CGRP into mice would increase anxiety and imbalance; and if mice further exposed to a vestibular stimulus would have their anxiety measures sharpened. We observed that CGRP alone increases imbalance, but not anxiety-like behaviors. However, the combination of CGRP followed by a vestibular challenge increased anxiety-like behaviors whereas a vestibular challenge alone was ineffective suggesting that anti-CGRP signaling therapies may be effective for the treatment of anxiety-like behaviors.