Anticonvulsant Effects of N-Arachidonoyl-Serotonin, a Dual Fatty Acid Amide Hydrolase Enzyme and Transient Receptor Potential Vanilloid Type-1 (TRPV1) Channel Blocker, on Experimental Seizures: The Roles of Cannabinoid CB1 Receptors and TRPV1 Channels

Selective blockade of anandamide hydrolysis, through the inhibition of the FAAH enzyme, has anticonvulsant effects, which are mediated by CB1 receptors. Anandamide, however, also activates TRPV1 channels, generally with an opposite outcome on neuronal modulation. Thus, we suggested that the dual FAAH and TRPV1 blockade with N-arachidonoyl-serotonin (AA-5-HT) would be efficacious in inhibiting pentylenetetrazole (PTZ)-induced seizures in mice. We also investigated the contribution of CB1 activation and TRPV1 blockade to the overt effect of AA-5-HT. In the first experiment, injection of AA-5-HT (0.3-3.0mg/kg) delayed the onset and reduced the duration of PTZ (60mg)-induced seizures in mice. These effects were reversed by pre-treatment with the CB1 antagonist, AM251 (1.0-3.0mg/kg). Finally, we observed that administration of the selective TRPV1 antagonist, SB366791 (0.1-1mg/kg), did not entirely mimic AA-5-HT effects. In conclusion, AA-5-HT alleviates seizures in mice, an effect inhibited by CB1 antagonism, but not completely mimicked by TRPV1 blockage, indicating that the overall effect of AA-5-HT seems to depend mainly on CB1 receptors. This may represent a new strategy for the development of drugs against seizures, epilepsies and related syndromes.