Background: Cannabis sativa-derived substances such as cannabidiol (CBD) have attracted increasing clinical interest and consist in a new perspective for treating some neurological and psychiatric diseases.
Aims: The aim of this work was to investigate the effect of acute treatment with CBD on panic-like defensive responses displayed by mice threatened by the venomous snake Bothrops jararaca.
Methods: Mice were habituated in the enriched polygonal arena for snake panic test. After recording the baseline responses of the tail-flick test, the prey were pretreated with intraperitoneal (i.p.) administrations of the endocannabinoid type 1 receptor (CB1) antagonist AM251 (selective cannabinoid 1 receptor antagonist with an IC50 of 8 nM) at different doses, which were followed after 10 min by i.p. treatment with CBD (3 mg/kg). Thirty minutes after treatment with CBD, mice were subjected to confrontations by B. jararaca for 5 min, and the following defensive responses were recorded: risk assessment, oriented escape behaviour, inhibitory avoidance and prey-versus-snake interactions. Immediately after the escape behaviour was exhibited, the tail-flick latencies were recorded every 5 min for 30 min.
Outcomes: Mice threatened by snakes displayed several anti-predatory defensive and innate fear-induced antinociception responses in comparison to the control. CBD significantly decreased the risk assessment and escape responses, with a consequent decrease in defensive antinociception. The CBD panicolytic effect was reversed by i.p. treatment with AM251.
Conclusions: These findings suggest that the anti-aversive effect of CBD depends at least in part on the recruitment of CB1 receptors.
Keywords: Bothrops jararaca; Cannabidiol; TRPV1 channel; cannabinoid type 1 receptor; defensive behaviour; prey versus snake confrontation; unconditioned fear-induced antinociception.