CB₁ receptor signalling mediates cannabidiol-induced panicolytic-like effects and defensive antinociception impairment in mice threatened by Bothrops jararaca lancehead pit vipers

Abstract

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.

Panicolytic‐like effects of environment enrichment on male mice threatened by Bothrops jararaca lancehead pit vipers

“…Interestingly, although the time spent on defensive alertness is minimal (less than 2 s in the entire session in the SE group), defensive attention/alertness is part of risk assessment behavior, also comprised of flat back approach and stretch attend posture, a set of key antipredatory reactions in a threatening situation. These anxiety‐related responses are so relevant than defensive immobility and escape behavior and are usually displayed by laboratory animals submitted to different psychobiological tests of anxiety, such as the elevated plus maze (Anseloni et al., 1999; Coimbra et al., 2017) and of panic attack, such as the polygonal arena for snake panic test (Almada et al., 2021, 2022; Coimbra et al., 2017; de Paula Rodrigues & Coimbra, 2022). Mice that were exposed to the enriched environment seem to need less of defensive attention strategy and showed more flat back approaches (Figure 3e) and an increased interaction with the predator (Figure 4a,b), consequently increasing crossings (Figure 4f) exploring more frequently the dangerous environment.…”

“…When mice from a non-enriched environment were exposed to the polygonal arena for the snake panic test, there were significant increases in both the behavioral index and duration of these risk assessment behaviors compared to the respective control group, considering the defensive attention (Figure 3a,b), the stretch attend posture (Figure 3c,d), and the flat back approach (Figure 3e,f). There was also a significant decrease in both behavioral index (Figure 4a) and duration (Figure 4b) of prey versus snake interaction, a significant increase in both behavioral index (Figure 4c) and duration (Figure 4d) of oriented escape, a significant increase in behavioral index of time spent in safe places (Figure 4e), and a decrease of crossings (Figure 4e such as the elevated plus maze (Anseloni et al, 1999;Coimbra et al, 2017) and of panic attack, such as the polygonal arena for snake panic test (Almada et al, 2021(Almada et al, , 2022Coimbra et al, 2017;de Paula Rodrigues & Coimbra, 2022). Mice that were exposed to the enriched environment seem to need less of defensive attention strategy and showed more flat back approaches (Figure 3e)…”

D2-like receptor activation by intranasal dopamine attenuates fear responses induced by electrical stimulation of the dorsal periaqueductal grey matter, but fails to reduce aversion to pit vipers and T-maze performance

“…The predatory and defensive behaviours displayed by the snakes were divided in three different strategies related to threatening behaviours (elevation of the head and anterior third of the body, dorsoventrally flattening of the body, rapid tail vibration against the substrate, threatening posture), innate fear-induced responses (retreat backward with threatening posture, hiding the head) and offensive behaviour (offensive/defensive strikes) defined as follows, as recently described for other species of genus Bothrops in our laboratory (de Paula Rodrigues and Coimbra, 2022): (i) threatening posture: defensive reactions in which the snakes elevated the first third of their bodies and assumed ‘S’ shapes (although continuous and rapid movements of the tail producing a warning sound are frequently displayed during threatening postures; this response was recorded separately in the reptile ethogram); (ii) threatening strikes: defensive behaviours during which the snakes strike without biting, with or without a warning sound with the tail preceding the pounce; (iii) offensive/defensive pounces: strikes with biting (in the case of offensive/defensive pounce, the experiment was interrupted, the prey was sacrificed with a lethal injection of ketamine/xylasine and discarded from the experiment, and the behavioural data related to the rodent that was sprung forward and poisoned were also discarded); (iv) defensive postures: defensive behaviours in which the snakes stay in the same place with their bodies in a coiled shape while protecting their heads on the upper body ring; (v) predatory behaviour: silent strikes, searching responses, and capture and feeding behaviours; in the present study, predatory behaviours were observed only during the previous feeding of the reptiles in the polygonal arena (hunting behaviour was considered to be an important index of the snakes’ adaptability to the experimental environment); and (vi) crossing: body movements through four delimited rectangles on the floor of the polygonal arena after crossing the border of each section line.…”

Endocannabinoid System: Chemical Characteristics and Biological Activity

“…Recently, interest in the medicinal properties of Cannabis sativa has resurged with the emergence of the eCB, offering not only new insights into the mechanisms underlying the therapeutic actions of cannabinoid-like molecules and phytocannabinoids but also novel molecular targets for the pharmacotherapy of pain [ 2 , 140 ]. Studies in animal models of acute pain showed that Δ9-THC, CBD, AEA, and synthetic cannabinoids such as CP55,940 and WIN 55,212-2 had antinociceptive actions [ 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 ]. In a model of chronic pain, AEA and cannabinoid ligands were effective treatments [ 147 , 149 , 150 , 151 , 152 ].…”