Dual FAAH/MAGL inhibition in migraine pain

This dataset comprises the findings obtained in the study aimed at investigating the effect of dual inhibition of anandamide and 2 arachidonyl glycerol (2-AG) catabolic pathways (FAAH and MAGL respectively) in the nitroglycerin (NTG)-based animal model of migraine. The dual inhibitor JZL195 was administered to male rats 2h after NTG or vehicle injection. Rats were then exposed to the open field and the orofacial formalin tests 4 hours after NTG or vehicle. At the end of the evaluations, they were sacrificed to evaluate calcitonin gene-related peptide (CGRP) serum levels and gene expression of CGRP and pro-inflammatory cytokines in the cervical spinal cord and the trigeminal ganglion.

We also investigated the effect of subtype-selective antagonist for cannabinoid receptors 1 and 2 (AM251 and AM630, respectively) on the behavioral JZL195 effects. The dual inhibitor significantly reduces the NTG-induced trigeminal hyperalgesia and pain-associated behavior, possibly via cannabinoid 1 receptors-mediated action, but it did not change the hypomotility and the anxiety behaviors induced by NTG. The decreased hyperalgesia was associated with a reduction in CGRP and cytokine gene expression levels in central and peripheral structures and reduced CGRP serum levels. These data suggest an antinociceptive synergy of the endocannabinoid action in peripheral and central sites, confirming that this system participates in reduction of cephalic pain signals.

The in vivo and ex vivo assessments were:

Distance (expressed in meters) travelled in the apparatus, time spent (expressed in seconds) in the center of the apparatus, number of rearing, time spent in grooming behavior (expressed in seconds) were evaluated in the open field test. Each animal was placed in a 92 x 92 cm arena and video recorded for 10 minutes. The analysis was done manually (for rearing and grooming) and with the ANY-Maze software (for total distance and time in the centre).

Pain-related behavior in the orofacial formalin test: the face rubbing was measured counting the seconds the animal spent grooming the injected area (upper lip, lateral to the nose) with the ipsilateral forepaw or hindpaw 0–6 min (Phase I) or 12–45 min (Phase II) after formalin injection (50 µl, s.c.). The observation time was divided into 15 blocks of 3 min each.

mRNA expression levels: calcitonin gene-related peptide (CGRP), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) mRNA were evaluated in cervical spinal cord and trigeminal ganglia. mRNA levels were measured by rt-PCR. All samples were assayed in triplicate and gene expression levels were calculated according to 2−∆∆Ct = 2− (∆Ct gene − ∆Ct housekeeping gene) formula by using Ct (cycle threshold) values.

CGRP protein levels in serum: the blood samples were collected in clot activator with gel separator serum tubes and centrifugated for 15 min at 1000×g at 2-8° C. Serum CGRP levels were measured using a commercial enzyme-linked immuno-sorbent assay (ELISA) kit (Elabsciences). Data are expressed as pg/ml.

Results: The dual inhibitor significantly reduced the NTG-induced trigeminal hyperalgesia and pain-associated behavior, possibly via cannabinoid 1 receptors-mediated action, but it did not change the hypomotility and the anxiety behaviors induced by NTG. The decreased hyperalgesia was associated with a reduction in CGRP and cytokine gene expression levels in central and peripheral structures and reduced CGRP serum levels.