Interictal type 1 cannabinoid receptor binding is increased in female migraine patients.

OBJECTIVE

To compare binding of the type 1 cannabinoid receptor (CB1R) between migraine patients and healthy volunteers.

BACKGROUND

It has been suggested that endocannabinoid deficiency may play a role in the pathophysiology of migraine. Nonetheless, biochemical studies substantiating this idea remain scarce and are faced with methodological shortcomings partly because of the difficulty to perform measurements of endocannabinoids within the central nervous system itself.

METHODS

An observational cross-sectional study was conducted in 20 female migraine patients and 18 healthy women matched for age and body mass index. Positron emission tomography acquisition was performed 90 minutes after intravenous injection of the radioligand [(18)F]MK-9470 to assess binding of [(18)F]MK-9470 to CB1R.

RESULTS

Binding of CB1 R was globally increased in migraine patients vs healthy controls (average gray matter difference +16%; P = .009, 2-sample 2-sided Student's t-test). There were no correlations between CB1R binding and any predefined migraine characteristics. Increases in CB1R binding were most pronounced in the anterior cingulate, mesial temporal, prefrontal, and superior frontal cortices.

CONCLUSIONS

The increased interictal CB1R binding, especially in brain regions that exert top-down influences to modulate pain, supports the idea that endocannibinoid deficiency is present in female patients suffering from episodic migraine.