Departamento de Farmacología, Facultad de Medicina, Universidad del País Vasco, UPV/EHU, Leioa, Bizkaia, Spain.
J Psychopharmacol. 2011 Jan;25(1):105-10. doi: 10.1177/0269881109358204. Epub 2010 Feb 8.
The interaction between brain GABAergic and endocannabinoid systems was evaluated by examining the quantitative and functional status of GABAergic receptors in cannabinoid CB(1) receptor knockout (CB(1)(-/-)) mice. To this aim, GABA(A) ([(3)H]-Muscimol binding assay), GABA(B) (baclofen-stimulated [(35)S]-GTPγS binding assay), GABA(A)α(1), GABA(A)α(2) and GABA(A)γ(2) receptors gene expression (real-time reverse transcriptase polymerase chain reaction [PCR]) were carried out in CB(1)(-/-) and wild-type mice (CB(1)(+/+)). [(3)H]-Muscimol binding assays revealed significant reduction in the density of GABA(A) receptors in CA2 (30%) and DG (28%) of the hippocampus, thalamus (40%), cingulate (28%) and motor cortex (35%) of CB(1)(-/-) mice. Functional activity of metabotropic GABA(B) receptors was measured by evaluating the ability of GABA(B) agonist baclofen to stimulate [(35)S]-GTPγS binding. The results showed significant reduced [(35)S]-GTPγS binding in CA1 (61%), CA3 (51%) and DG (60%) of CB(1)(-/-) mice compared with CB(1)(+/+) mice. Real-time reverse transcriptase PCR was carried out for evaluating gene expression of α(1), α(2) and γ(2) subunits of GABA(A) receptor in the amygdala. The results showed significant reduced GABA(A)α(1) (50%) and GABA(A)α(2) (40%) receptor subunits gene expression in the amygdala of CB(1)(-/-) mice. No difference was observed in GABA(A)γ(2) receptor subunit gene expression. This study provides strong evidence of the involvement of CB(1) receptors in the control of GABAergic responses mediated by GABA(A) and GABA(B) receptors, and suggests a possible role of the endocannabinoid system in the regulation of anxiety-related disorders.
本研究通过检测大麻素 CB1 受体敲除（CB1(-/-)）小鼠中 GABA 能受体的定量和功能状态，评估了脑 GABA 能和内源性大麻素系统之间的相互作用。为此，我们在 CB1(-/-)和野生型（CB1(+/+)）小鼠中进行了 GABA(A)（[3H]-Muscimol 结合测定）、GABA(B)（巴氯芬刺激[35S]-GTPγS 结合测定）、GABA(A)α1、GABA(A)α2 和 GABA(A)γ2 受体基因表达（实时逆转录聚合酶链反应 [PCR]）。[3H]-Muscimol 结合测定显示，CB1(-/-)小鼠海马 CA2（30%）和 DG（28%）、丘脑（40%）、扣带回（28%）和运动皮层（35%）的 GABA(A)受体密度显著降低。通过评估 GABA(B)激动剂巴氯芬刺激[35S]-GTPγS 结合的能力，测量代谢型 GABA(B)受体的功能活性。结果显示，与 CB1(+/+)小鼠相比，CB1(-/-)小鼠 CA1（61%）、CA3（51%）和 DG（60%）的[35S]-GTPγS 结合显著减少。实时逆转录 PCR 用于评估杏仁核中 GABA(A)受体α1、α2 和 γ2 亚基的基因表达。结果显示，CB1(-/-)小鼠杏仁核中 GABA(A)α1（50%）和 GABA(A)α2（40%）受体亚基基因表达显著降低。GABA(A)γ2 受体亚基基因表达无差异。本研究为 CB1 受体参与 GABA 能受体介导的 GABA 能和 GABA(B)反应的控制提供了有力证据，并提示内源性大麻素系统可能在调节焦虑相关疾病中发挥作用。
