Cortical hyper excitability due to enhanced glutamatergic activity has been implicated in migraine pathophysiology but direct evidence is lacking.
Migraine is a
frequent neurological disorder but its pathophysiology is unclear. In this
research study, the role of cortical glutamate levels in pathophysiology of
migraine has been determined and it has been reported that the glutamate levels
in migraine without aura increases as compared to control.
Cortical hyper
excitability due to enhanced glutamatergic activity has been implicated in
migraine pathophysiology but direct evidence is lacking. Here we assessed
glutamate levels and intracellular mobility of glutamate in the visual cortex
of migraineurs in-between attacks.
The study
included 50 migraineurs (23 with aura and 27 without aura) and 24 age- and
gender-matched non-headache controls. The research team used proton magnetic
resonance spectroscopy (1H-MRS) and diffusion weighted spectroscopy at 7 T with
a single volume of interest (2 × 2 × 3 cm) located in the primary and secondary
visual cortex. For 1H-MRS also a semi-LASER sequence with water referencing for
absolute quantification was used. For diffusion weighted spectroscopy an
adapted PRESS sequence was used with gradients applied in three directions and
two different gradient amplitudes. Between-group differences were evaluated
using analysis of co variance with the grey matter fraction in the volume of
interest as co variate and post hoc comparisons with Bonferroni correction.
Glutamate
concentrations differed between groups (P = 0.047) and were higher in
migraineurs without aura (mean ± standard deviation: 7.02 ± 0.50 mM) compared
to controls (mean ± standard deviation: 6.40 ± 0.78 mM, P = 0.042). The
apparent diffusion coefficient of glutamate was similar among groups (P= 0.129)
suggesting similar inter- and intracellular mobility of glutamate in all three
study groups. No differences were observed for concentrations and diffusion
constants of other metabolites.
The present study
suggests that interictal glutamate levels are increased in the visual cortex of
migraineurs without aura, supporting the hypothesis of cortical
hyperexcitability in migraine.
Brain
Cortical glutamate in migraine
Ronald Zielman et al.
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