Abstract

During adolescence dopaminergic neurotransmission shows transient changes until reaching adulthood. The administration of CB1 agonists such as WIN55212-2 during adulthood increases dopamine extracellular levels. However, the effects of acute administration of cannabinoids on nigrostriatal dopamine neurotransmission during adolescence are not fully elucidated. The aim of this research is to compare dorsolateral striatum (DLS) dopamine (DA) dynamics and to study the effect of WIN55212-2 on DLS DA dynamics during adolescence and adulthood. No-net flux microdialysis experiments were carried out in adolescent (post-natal day 35-40) and young-adult (post-natal day 70-75) urethane-anesthetized rats. Basal DA dialysate, DA extraction fraction (Ed) and extracellular concentration of DA (C-ext) in DLS were assessed after an acute injection of WIN55212-2 (1.2 mg/kg) or vehicle. An increased basal DA dialysate and DA Ed were observed during adolescence compared to adulthood. Moreover, WIN55212-2 increases DLS DA C-ext rising basal DA dialysate in adulthood and decreasing DA Ed in adolescence. Our results suggest that an age-dependent mechanism underlies the effect of WIN 55212-2 on DA balance between release and uptake in DLS.