A dual inhibitor of FAAH and TRPV1 channels shows dose-dependent effect on depression-like behaviour in rats

Abstract

Objective: The cannabinoid receptor 1 (CB1) and transient receptor potential cation channel subfamily V member 1 (TRPV1) are proposed to mediate opposite behavioural responses. Their common denominator is the endocannabinoid ligand anandamide (AEA), which is believed to mediate antidepressant-like effect via CB1-R stimulation and depressive-like effect via TRPV1 activation. This is supposed to explain the bell-shaped dose-response curve for anandamide in preclinical models. Methods: We investigated this assumption by administering the dual inhibitor of AEA hydrolysis and TRPV1 activation N -arachidonoyl- serotonin (AA-5HT) into the medial prefrontal cortex of rats. AA-5HT was given in three different doses (0.125, 0.250, 0.500 nmol/0.4 μ l/side) and rat behaviour was assessed in the forced swim test. Results: Our results show signi fi cant antidepressant-like effect of AA-5HT (0.250 nmol) but no effects of low or high doses. The effect of 0.250 nmol AA-5HT was partially attenuated when coadministering the inverse CB1-agonist rimonabant (1.6 μ g). Conclusion: A 0.250 nmol of AA-5HT administration into the medial prefrontal cortex induced a signi fi cant antidepressant-like effect that was partially attenuated by locally blocking CB1-receptor