Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USA.
Department of Psychiatry and Human Behavior, University of California, Irvine, CA, USA.
Addict Biol. 2022 Jul;27(4):e13178. doi: 10.1111/adb.13178.
Alcohol dependence results in long-lasting neuroadaptive changes in meso-corticolimbic system, especially in the nucleus accumbens (NAc), which drives relapse-like ethanol drinking upon abstinence or withdrawal. Within NAc, altered glutamate homeostasis is one of the neuroadaptive changes caused by alcohol dependence. Accumbal glutamate homeostasis is tightly maintained through glutamate transporter 1 (GLT-1) and cystine-glutamate antiporter (xCT). But the role of GLT-1 and xCT in relapse-like ethanol drinking is poorly understood. Here, we used alcohol-preferring (P) rats in relapse-like ethanol drinking paradigm to (a) determine the effect of relapse-like ethanol drinking on gene and protein expression of GLT-1 and xCT in NAc, measured by quantitative polymerase chain reaction (qPCR) and Western blot, respectively; (b) examine if glutamate uptake is affected by relapse-like ethanol drinking in NAc, measured by radioactive glutamate uptake assay; (c) elucidate if upregulation of either/both GLT-1 or/and xCT through ceftriaxone is/are required to attenuate relapse-like ethanol drinking. The GLT-1 or xCT protein expression was suppressed during ceftriaxone treatments through microinjection of GLT-1/xCT anti-sense vivo-morpholinos. We found that relapse-like ethanol drinking did not affect the gene and protein expression of GLT-1 and xCT in NAc. The glutamate uptake was also unaltered. Ceftriaxone (200 mg/kg body weight, i.p.) treatments during the last 5 days of abstinence attenuated relapse-like ethanol drinking. The suppression of GLT-1 or xCT expression prevented the ceftriaxone-induced attenuation of relapse-like ethanol drinking. These findings confirm that upregulation of both GLT-1 and xCT within NAc is crucial for ceftriaxone-mediated attenuation of relapse-like ethanol drinking.
酒精依赖导致中皮质边缘系统（meso-corticolimbic system），尤其是伏隔核（nucleus accumbens，NAc），产生持久的神经适应性变化，导致戒断或停药后出现类似复发的乙醇饮用量增加。在 NAc 内，谷氨酸稳态的改变是由酒精依赖引起的神经适应性变化之一。通过谷氨酸转运体 1（glutamate transporter 1，GLT-1）和胱氨酸-谷氨酸反向转运体（cystine-glutamate antiporter，xCT），NAc 内的谷氨酸稳态得到紧密维持。但是，GLT-1 和 xCT 在类似复发的乙醇饮用量中的作用尚未完全清楚。在这里，我们使用在类似复发的乙醇饮用量模型中喜欢酒精的（P）大鼠（a）通过定量聚合酶链反应（quantitative polymerase chain reaction，qPCR）和 Western blot 分别确定类似复发的乙醇饮用量对 NAc 中 GLT-1 和 xCT 的基因和蛋白表达的影响；（b）通过放射性谷氨酸摄取测定来检查类似复发的乙醇饮用量是否影响 NAc 中的谷氨酸摄取；（c）阐明通过头孢曲松（ceftriaxone）上调 GLT-1 或/和 xCT 是否/需要减轻类似复发的乙醇饮用量。通过 NAc 中的 GLT-1/xCT 反义 vivo-morpholinos 微注射，在头孢曲松治疗期间抑制 GLT-1 或 xCT 蛋白表达。我们发现，类似复发的乙醇饮用量不会影响 NAc 中 GLT-1 和 xCT 的基因和蛋白表达。谷氨酸摄取也没有改变。在戒断的最后 5 天内，用头孢曲松（200mg/kg 体重，腹腔内注射）治疗可减轻类似复发的乙醇饮用量。抑制 GLT-1 或 xCT 表达可防止头孢曲松诱导的类似复发的乙醇饮用量减少。这些发现证实，NAc 内 GLT-1 和 xCT 的上调对于头孢曲松介导的类似复发的乙醇饮用量减少至关重要。
