Department of Anatomy and Cell Biology, University of Illinois Chicago - College of Medicine, Chicago, IL, 60612, USA.
Neuropsychopharmacology. 2024 Aug;49(9):1417-1424. doi: 10.1038/s41386-024-01844-z. Epub 2024 Mar 11.
Prefrontal cortex (PFC) maturation during adolescence is characterized by structural and functional changes, which involve the remodeling of GABA and glutamatergic synapses, as well as changes in the endocannabinoid system. Yet, the way PFC endocannabinoid signaling interacts with local GABA and glutamatergic function to impact its processing of afferent transmission during the adolescent transition to adulthood remains unknown. Here we combined PFC local field potential recordings with local manipulations of 2-AG and anandamide levels to assess how PFC endocannabinoid signaling is recruited to modulate ventral hippocampal and basolateral amygdalar inputs in vivo in adolescent and adult male rats. We found that the PFC endocannabinoid signaling does not fully emerge until late-adolescence/young adulthood. Once present, both 2-AG and anandamide can be recruited in the PFC to limit the impact of hippocampal drive through a CB1R-mediated mechanism whereas basolateral amygdalar inputs are only inhibited by 2-AG. Similarly, the behavioral effects of increasing 2-AG and anandamide in the PFC do not emerge until late-adolescence/young adulthood. Using a trace fear conditioning paradigm, we found that elevating PFC 2-AG levels preferentially reduced freezing behavior during acquisition without affecting its extinction. In contrast, increasing anandamide levels in the PFC selectively disrupted the extinction of trace fear memory without affecting its acquisition. Collectively, these results indicate a protracted recruitment of PFC endocannabinoid signaling, which becomes online in late adolescence/young adulthood as revealed by its impact on hippocampal and amygdalar-evoked local field potential responses and trace fear memory behavior.
前额皮质(prefrontal cortex,PFC)在青春期的成熟过程中表现为结构和功能的变化,涉及 GABA 和谷氨酸能突触的重塑,以及内源性大麻素系统的变化。然而,PFC 内源性大麻素信号如何与局部 GABA 和谷氨酸能功能相互作用,以影响其在青春期向成年期过渡过程中传入传递的处理,目前尚不清楚。在这里,我们结合 PFC 局部场电位记录和 2-AG 和大麻素水平的局部操作,评估 PFC 内源性大麻素信号如何被招募来调节体内青春期和成年雄性大鼠腹侧海马和基底外侧杏仁核的传入。我们发现,PFC 内源性大麻素信号直到青春期后期/成年早期才完全出现。一旦出现,2-AG 和大麻素都可以在 PFC 中被招募,通过 CB1R 介导的机制来限制海马驱动的影响,而基底外侧杏仁核的输入仅被 2-AG 抑制。同样,增加 PFC 中 2-AG 和大麻素的行为效应直到青春期后期/成年早期才出现。使用痕迹恐惧条件反射范式,我们发现,增加 PFC 中的 2-AG 水平可以优先减少获得过程中的冻结行为,而不影响其消退。相比之下,增加 PFC 中的大麻素水平选择性地破坏了痕迹恐惧记忆的消退,而不影响其获得。总的来说,这些结果表明 PFC 内源性大麻素信号的募集时间延长,这在青春期后期/成年早期通过其对海马和杏仁核诱发的局部场电位反应和痕迹恐惧记忆行为的影响而显现出来。