Effects of CP 55,940 on anxiety-like behaviours in Lewis and Wistar rats: Part B Studies utilising the social interaction and light-dark emergence models of anxiety with assessment of ataxia using the rotarod

Studies utilising the social interaction and light-dark emergence models of anxiety with assessment of ataxia using the rotarod. The current chapter aims to extend the work conducted in Chapter 2 by testing the generality of the findings observed in the predatory odour avoidance, open area avoidance and the conditioned USV models of anxiety. Chapter 2 provided evidence showing that Lewis rats were less susceptible to the anxiogenic effects of CP 55,940 in comparison to Wistar rats as assessed by these animal models of anxiety. This provides indirect evidence in support of the hypothesis that Lewis rats may be more susceptible to the rewarding effects of cannabinoids (Lepore et al., 1996a) because they are less susceptible to the anxiogenic effects of such drugs. Anxiety is a heterogeneous phenomenon and it has been suggested that different animal models of anxiety may assay different types of anxiety (File, 1996a; File et al., 1996b; Rodgers, 1997). Thus, two further models will be utilised in the current chapter, namely, the social interaction test and light-dark emergence paradigm to assay any distinct effects CP 55,940 may have on anxiety-like behaviour in these models. Previous research into the effects of cannabis and ∆ 9-THC on the social behaviour of animals, for the most part, is limited to studies on aggression. These studies demonstrate that aggression in rats, mice and non-human primates is decreased by the administration of ∆