Cannabinoid and opioid modulation of social play behavior in adolescent rats: Differential behavioral mechanisms

Abstract

We have recently shown that the pharmacological mechanisms through which cannabinoid and opioid drugs influence social play behavior in adolescent rats can be partially dissociated. Here, we characterize the effects of the direct cannabinoid agonist WIN55,212-2, the indirect cannabinoid agonist URB597 and the opioid agonist morphine on social play at the behavioral level. By treating either one or both partners of the test dyad, we show that these drugs differentially affect play solicitation and play responsiveness. By testing these drugs in animals which were either familiar or unfamiliar to the test cage, we show that environmental factors differentially modulate the effects of cannabinoid and opioid drugs on social play. These results support and extend our previous findings suggesting that, although cannabinoid and opioid systems interact in the modulation of social play behavior in adolescent rats, they do so through partially dissociable behavioral and pharmacological mechanisms.

Distinct roles of the endocannabinoids anandamide and 2-arachidonoylglycerol in social behavior and emotionality at different developmental ages in rats

“…JZL195 (0.01, 0.1 and 1 mg/kg) or its vehicle was administered 2 h before testing; SR141716A was administered 30 min before JZL195, at a dose that did not induce effects by itself (0.1 mg/kg in adolescent rats (Trezza and Vanderschuren, 2008b) and 1 mg/kg in adult rats (Gobbi et al, 2005;Sciolino et al, 2011). Drug doses and pre-treatment intervals were based on the literature (Long et al, 2009b;Trezza and Vanderschuren, 2008b) and on pilot experiments. Solutions were freshly prepared on the day of the experiment and were administered in a volume of 2 ml/kg in adolescent rats and 1 ml/kg in adult rats.…”

“…Social behavior was assessed as previously described Trezza and Vanderschuren, 2008a, 2008b, 2009Vanderschuren et al, 2008).…”

Maternal exposure to environmental enrichment before and during gestation influences behaviour of rat offspring in a sex-specific manner

“…The behavioural assessments were performed in a sound-attenuated, lighting-and temperature-controlled room, as previously reported [27,28]. Briefly, the testing arena consisted of a Plexiglas cage measuring 40 x 40 x 40 cm with approximately 2 cm of wood shavings covering the floor.…”

Social Play Behavior in Adolescent Rats is Mediated by Functional Activity in Medial Prefrontal Cortex and Striatum

“…During the social encounter, animals may also display social behaviors not directly associated with play, such as sniffing or grooming the partner's body (Panksepp and Beatty, 1980;Vanderschuren et al, 1995). As social play behavior in rats strongly depends on the playfulness of its partner (Pellis and McKenna, 1992;Trezza and Vanderschuren, 2008), in the present study, both animals in a play pair were similarly treated and a pair of animals was considered as one experimental unit. The following parameters were therefore scored per pair of animals:…”

“…Proper social interactions during this phase of life are thought to be important for social and cognitive development Špinka et al, 2001;Vanderschuren et al, 1997). Indeed, social isolation of rats during the juvenile/early adolescent phases produces long-lasting impairments in social capacities and cognitive control of behavior, even after prolonged re-socialization (van den Berg et al, 1999;Baarendse et al, 2013), and social traumas during childhood and adolescence can increase the risk for psychopathology in later life (Braun and Bock, 2011). Likewise, abnormalities in social play behavior are observed in childhood psychiatric disorders such as autism and attention deficit/ hyperactivity disorder (Alessandri, 1992;Manning and Wainwright, 2010).…”