Interactions between the nitrergic and the endocannabinoid system in rats exposed to the elevated T maze

Objective: the aim of this study was to test the hypothesis that synthesis of nitric oxide (NO) and activation of CB1 receptors have opposite effects in a behavioural animal model of panic and anxiety.

Methods: to test the hypothesis male Wistar rats were exposed to the elevated T maze (ETM) model under the following treatments: L-Arginine (L-Arg) was administered before treatment withWIN55,212-2, a CB1 receptor agonist ; AM251, a CB1 antagonist, was administered before treatment with L-Arg. All treatments were by intraperitoneal route.

Results: the CB1 receptor agonist, WIN55,212-2 (1 mg/kg), induced an anxiolytic-like effect which was prevented by pretreatment with an ineffective dose of L-Arg (1 mg/kg). Administration of AM251 (1 mg/kg), a CB1 antagonist before treatment with L-Arg (1 mg/kg) did not produce anxiogenic-like responses.

Conclusion: altogether, this study suggests that the anxiolytic-like effect of cannabinoids may occur though modulation of NO signaling.