Effects of NSAIDs on the Release of Calcitonin Gene-Related Peptide and Prostaglandin E2 from Rat Trigeminal Ganglia

Abstract

Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used to treat migraine, but the mechanisms of their effects in this pathology are not fully elucidated. The trigeminal ganglia and calcitonin gene-related peptide (CGRP) have been implicated in the pathophysiology of migraine. The release of CGRP and prostaglandin E₂ (PGE₂) from freshly isolated rat trigeminal ganglia was evaluated after oral administration of nimesulide, etoricoxib, and ketoprofen, NSAIDs with different pharmacological features. Thirty minutes after oral administration, nimesulide, 10 mg/Kg, decreased the GCRP release induced by an inflammatory soup, while the other NSAIDs were ineffective at this point in time. Two hours after oral nimesulide (5 and 10 mg/Kg) and ketoprofen (10 mg/Kg), but not of etoricoxib, a significant decrease in the CGRP release was observed. All drugs reduced PGE₂, although with some differences in timing and doses, and the action on CGRP does not seem to be related to PGE₂ inhibition. The reduction of CGRP release from rat trigeminal ganglia after nimesulide and ketoprofen may help to explain the mechanism of action of NSAIDs in migraine. Since at 30 minutes only nimesulide was effective in reducing CGRP release, these results suggest that this NSAID may exert a particularly rapid effect in patients with migraine.

Figure 1

(a) Effect of oral administration of 10 mg/Kg nimesulide, ketoprofen, etoricoxib, or water on CGRP release from trigeminal ganglia after in vitro stimulation with inflammatory soup (IS). Thirty minutes and 2 hours after administration, rats were sacrificed, trigeminal ganglia were collected and maintained in vitro with DMEM alone for 5 minutes, then medium was collected, and ganglia were stimulated with IS for another 5 minutes. CGRP released in media basally and upon stimulation was measured by EIA. CGRP levels are expressed as % of basal values (measured before addition of IS) that were normalised to 100. Values are mean ± SEM of 6 animals. ^∗p < 0,05; ^∗∗∗p < 0,001 versus basal; °p < 0,05; °°p < 0,01; °°°p < 0,001 versus water + IS. (b) Dose-dependent inhibition of CGRP release in vitro by trigeminal ganglia after stimulation with IS by nimesulide, ketoprofen, and etoricoxib. Rats were treated orally with NSAIDs at the doses of 10, 5, and 1 mg/Kg. Two hours after administration, rats were sacrificed, and experiment was carried on as in (a). Values are mean ± SEM of 6 animals. ^∗∗p < 0,01; ^∗∗∗p < 0,001 versus basal; °p < 0,05; °°°p < 0,001 versus water + IS.

Figure 2

(a) Effect of oral administration of 10 mg/Kg nimesulide, ketoprofen, etoricoxib, or water on PGE₂ release by trigeminal ganglia both in basal condition and after in vitro stimulation with inflammatory soup (IS). Thirty minutes and 2 hours after administration, rats were sacrificed, trigeminal ganglia were collected and maintained in vitro with DMEM alone for 5 minutes, then medium was collected, and ganglia were stimulated with inflammatory soup for another 5 minutes. Values are mean ± SEM of 6 animals; ^∗∗∗p < 0,001 versus water; °°p < 0,01; °°°p < 0,001 versus water + IS. (b) Dose-response curve of the inhibition by nimesulide, ketoprofen, and etoricoxib treatments on in vitro basal and stimulated PGE₂ releases by trigeminal ganglia. Rats were treated orally with NSAIDs at the doses of 10, 5, and 1 mg/Kg. Two hours after administration, rats were sacrificed, trigeminal ganglia were collected and treated as in (a). PGE₂ release was measured in medium by EIA method. Values are mean ± SEM of 6 animals ^∗∗p < 0,01, ^∗∗∗p < 0,001 versus water; °°p < 0,01; °°°p < 0,001 versus water + IS.