The endocannabinoid system is responsible for regulating a spectrum of physiological activities and plays a critical role in the developing brain. During adolescence, the endocannabinoid system is ...particularly sensitive to external insults that may change the brain’s developmental trajectory. Cannabinoid receptor type 2 (CB2R) was initially thought to predominantly function in the peripheral nervous system, but more recent studies have implicated its role in the mesolimbic pathway, a network largely attributed to reward circuitry and reward motivated behavior, which undergoes extensive changes during adolescence. It is therefore important to understand how CB2R modulation during adolescence can impact reward-related behaviors in adulthood. In this study, adolescent male rats (postnatal days 28–41) were exposed to a low or high dose of the CB2R antagonist/inverse agonist SR144528 and Pavlovian autoshaping and instrumental conditional behavioral outcomes were measured in adulthood. SR144528-treated rats had significantly slower acquisition of the autoshaping task, seen by less lever pressing behavior over time
F
(2, 19)
= 5.964,
p
= 0.010. Conversely, there was no effect of adolescent SR144528 exposure on instrumental conditioning. These results suggest that modulation of the CB2R in adolescence differentially impacts reward-learning behaviors in adulthood.
Antenatal corticosteroid (ACS) treatment in cases of preterm birth (<37 weeks of gestation) significantly decreases neonatal morbidity and mortality, as it replaces an important endogenous surge in ...glucocorticoids that occurs in late gestation. While there are minimal short-term risks of ACS treatment, studies have demonstrated long term behavioural and structural impacts of ACS treatment on adult offspring. The underlying mechanisms of these effects are still unclear. One potential explanation is modulation by epigenetic mechanisms, including miRNA. This project seeks to identify differences in miRNA expression patterns in the medial prefrontal cortex of postnatal day 1 female guinea pig offspring that had been exposed to a single course of ACS treatment. A miRNA microarray showed no significant differences between control and treated animals. This is an important finding as it helps us understand the role epigenetic factors play at different time points of development in the modulation of the programming effects of ACS treatment.
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