The modulation of striatonigral and nigrotectal pathways by CB1 signalling in the substantia nigra pars reticulata regulates panic elicited in mice by urutu-cruzeiro lancehead pit vipers

Functional activation of the periaqueductal gray matter during conditioned and unconditioned fear in guinea pigs confronted with the Boa constrictor constrictor snake

“…These behavioral findings were previously reported by Leite-Panissi et al (26). The same reactions have been displayed by rats, Syrian hamsters, and mice exposed to either venomous (5,22,23,27) or constrictor snakes (23,28) in polygonal arenas. These snakes have been ethologically validated as experimental models of either panic attack (5,23) or post-traumatic stress disorder (29).…”

“…In the laboratory, the brain circuit underlying defensive behaviors is generally studied by various models of aversive stimuli exposure, anxiogenic drugs, and electric and optogenetic stimulation (9,(20)(21)(22). However, reports based on aversive stimuli that are ethologically relevant to induce innate fear-or panic attack-like responses are lacking.…”

Panic‐like responses of female Wistar rats confronted by Bothrops alternatus pit vipers, or exposure to acute hypoxia: Effect of oestrous cycle

“…The experimental apparatus consists in an enriched polygonal arena (154 × 72 × 64 cm, crystal acrylic, with insulfilm) arranged on a granite surface (170 × 85 × 02 cm) and equipped with an artificial burrow (36 × 26 × 12.5 cm, with two outlets diametrically opposite) and two small elevated platforms (7 × 4 × 10.5 cm) for escape, accessed by acrylic stairs. This prey‐versus‐snake confrontation environment (see Figure 1) has been described in more detail in previous reports from our laboratory (Almada & Coimbra, 2015; Almada et al, 2015, 2021; Coimbra, Calvo, et al, 2017; Coimbra, Mendes‐Gomes, et al, 2017; Coimbra, Paschoalin‐Maurin, et al, 2017; dos Anjos‐Garcia & Coimbra, 2019, 2020).…”

“…Confrontation by a predator in a semi‐naturalistic environment (the enriched polygonal arena) represents an ethologically relevant challenge to survival, which elicits a sophisticated behavioural repertoire to promote survival by first assessing the level of threat and then engaging in defensive behaviour if the threat is judged to pose a risk to survival. In large enriched polygonal arenas for snakes, such as the one used in the present study, the initial risk assessment approach‐avoidance conflict behaviour elicited by the relatively distant threat is considered to reflect anxiety, whilst unconditioned freezing (defensive immobility) and escape responses evoked by the real proximal threat have been associated with panic (Almada et al, 2021; Blanchard, Griebel, & Blanchard, 2001; Blanchard, Hynd, et al, 2001; Coimbra, Calvo, et al, 2017; Paschoalin‐Maurin et al, 2018). In the presence of the snake, both males and females initially displayed anxiety‐like behaviour (risk assessment) followed by panic‐like escape response.…”

“…We utilised the rodent's innate fear of snakes to develop and validate a rodent‐versus‐snake confrontation paradigm test using Wistar rats as prey. Confrontation with a venomous snake in the polygonal arena for snake panic test elicits a mix of anxiety‐ and panic attack‐related behaviours in male rats (Calvo, Almada, et al, 2019; Calvo, Lobão‐Soares, et al, 2019; Coimbra, Mendes‐Gomes, et al, 2017), golden hamsters (Paschoalin‐Maurin et al, 2018), and mice (Almada et al, 2021; Coimbra, Calvo, et al, 2017; dos Anjos‐Garcia & Coimbra, 2019, 2020; Lobão‐Soares et al, 2008; Mendes‐Gomes, Paschoalin‐Maurin, et al, 2020). The test recruits similar cerebral and midbrain structures (Mendes‐Gomes, Motta, et al, 2020; Paschoalin‐Maurin et al, 2018) to those already reported to be related to the organisation of antipredatory behaviour (Blanchard et al, 2005; Canteras et al, 1997; Canteras & Goto, 1999) and panic‐like responses (Biagioni et al, 2013; Ullah et al, 2015, 2017; Wilent et al, 2010).…”