Sex-dependent central amygdala physiology after supradural CGRP exposure is associated with migraine-like behaviors

Calcitonin gene-related peptide (CGRP) is a key mediator of migraine, but the mechanisms through which meningeal CGRP engages central circuits involved in the sensory and affective dimensions of migraine remain incompletely understood. Here, we tested if supradural CGRP is sufficient to induce migraine-like sensory and affective behaviors and if these effects are associated with sex-dependent changes in parabrachial-central amygdala (PB-CeA) signaling.

Adult male and female C57BL/6J mice received supradural CGRP or vehicle. Behavioral testing, whole-cell patch-clamp recordings, and qPCR analyses were performed 3 h later.

CGRP induced robust periorbital mechanical allodynia selectively in females, while hindpaw mechanical thresholds were reduced in both sexes, with a greater effect in females. CGRP also increased avoidance-like behavior in both sexes, reflected by decreased open-arm exploration in the elevated plus maze and decreased time spent in the light compartment of the light-dark box. Whole-cell patch-clamp recordings from neurons in the right latero-capsular central amygdala in CGRP-exposed mice revealed higher excitability and larger PB-evoked excitatory postsynaptic currents in females than males. Ex vivo bath application of the CGRP receptor antagonist CGRP₈₋₃₇ was used to test local CGRP receptor sensitivity and selectively decreased excitability and PB-evoked excitatory transmission in females, while paired-pulse ratio remained unchanged in both sexes. In addition, qPCR analysis identified region- and sex-dependent transcriptional changes after supradural CGRP, with the most consistent molecular effects observed in the right PBN and more limited changes in the right CeA.

Together, these findings show that supradural CGRP is sufficient to produce sex-differentiated mechanical hypersensitivity and avoidance-like behavior and is associated with sex-dependent physiological and transcriptional changes, including a right-sided pattern of transcriptional effects. These results identify the PB-CeA pathway as a candidate substrate linking meningeal CGRP signaling to central mechanisms relevant to hypersensitivity and amygdala plasticity that is more pronounced in females.