Murphy Zackari D, Mulugeta Ruth, Tran Alex, Ferguson Susan M
Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98195.
Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101.
Addict Neurosci. 2023 Dec;8. doi: 10.1016/j.addicn.2023.100122. Epub 2023 Jul 28.
Addiction is a disorder that can be characterized in part as the constant pursuit of a particular substance despite negative consequences. Although the orbitofrontal cortex (OFC) is known to regulate risk-taking more generally and be critical to the development of addiction, its role in regulating drug use under risk-taking conditions is unknown. To address this, we examined drug-taking and drug-seeking in male and female rats under conditions where cocaine infusions were paired with foot shock punishment 50% of the time and combined this paradigm with cFos immunohistochemistry. We found that rats that showed higher levels of drug-taking and drug-seeking prior to punishment showed decreased responding during self-administration sessions under risky conditions and lower levels of c-Fos expression in the lateral but not medial OFC. However, despite these initial differences in responses to infusions paired with foot shocks, all rats showed decreased responding with additional punishment sessions. We then used chemogenetic viral approaches to examine how altering activity of the lateral OFC affects drug-taking and drug-seeking during punished drug use. Although there was no effect of G DREADD-mediated inhibition of the lateral OFC on these behaviors, G DREADD-mediated activation increased drug-taking and drug-seeking when drug use was associated with foot shock 50% of the time. Interestingly, this manipulation had no effect on non-risky self-administration behavior. These results suggest that the involvement of lateral OFC in cocaine use is context-sensitive and influences decision-making based on negative outcomes.
成瘾是一种疾病,其部分特征是不顾负面后果持续追求某种特定物质。虽然已知眶额皮质(OFC)更广泛地调节冒险行为且对成瘾的发展至关重要,但其在冒险条件下调节药物使用中的作用尚不清楚。为了解决这个问题,我们在50%的时间里将可卡因注射与足部电击惩罚配对的条件下,研究了雄性和雌性大鼠的药物摄取和觅药行为,并将这种范式与cFos免疫组织化学相结合。我们发现,在惩罚前表现出较高药物摄取和觅药水平的大鼠,在冒险条件下的自我给药过程中反应减少,并且在外侧而非内侧眶额皮质中c-Fos表达水平较低。然而,尽管在与足部电击配对的注射反应上存在这些初始差异,但所有大鼠在额外的惩罚过程中反应都减少了。然后,我们使用化学遗传学病毒方法来研究改变外侧眶额皮质的活性如何影响惩罚性药物使用期间的药物摄取和觅药行为。虽然G DREADD介导的外侧眶额皮质抑制对这些行为没有影响,但当50%的时间里药物使用与足部电击相关时,G DREADD介导的激活增加了药物摄取和觅药行为。有趣的是,这种操作对非冒险性自我给药行为没有影响。这些结果表明,外侧眶额皮质参与可卡因使用是情境敏感的,并基于负面结果影响决策。