GABAA RECEPTOR POPULATIONS IN HIPPOCAMPUS AND THALAMUS

大多数中枢神经系统神经元表达GABAA受体(GABAARs)，GABAARs介导抑制。 GABAARs由5个亚基组成。其中两个是α，两个是β亚基。第五个通常是γ2或δ。 虽然第五个不是门控所必需的，但在重组受体中，γ2或δ亚单位的存在 极大地改变了生物物理和药理特性。在天然细胞中，第五亚单位被认为是 标记在强直(δ亚基)和相控(γ2亚基)抑制中的特定作用。我们不理解 由这些亚基定义的受体亚类的生理贡献，尽管有新的证据 提示受体亚类在精神功能中有不同的作用，治疗药物针对一种或一种 另一个子类产生不同的精神活动效果。例如，可能具有δ选择性作用的神经类固醇是新兴的抗抑郁药物。不存在将δ受体与γ2分离的拮抗剂 对于受体来说，关于它们各自的贡献仍然有很多问题。我们被迫接受了 以往方法的缺点和选择性对抗创造老鼠的历史优势 在γ2或δ中有点突变的品系，这赋予了对非竞争性伽巴的抗性 拮抗剂印防己毒素。初步数据显示了这些工具的潜在效用。在这里，我们测试最重要的 假设δ受体在包括海马区在内的皮质区域中介导δ驱动的去抑制。我们会 探索δ受体在已知表达δ的细胞类别中的作用，这可能为δ驱动的细胞提供底物 解除抑制。最后，我们将测试δ受体对海马体和丘脑回路的影响 对神经精神疾病很重要，假设δ驱动的去抑制驱动γ振荡 负责认知的各个方面，δ受体分别驱动丘脑皮质回路中的睡眠纺锤波。 我们最近的结果已经改变了流行的观点，并使我们能够询问受体的作用 细胞和网络功能的亚群。我们的方法将指导合理的药物开发，旨在 抑制力。

Most CNS neurons express GABAA receptors (GABAARs), which mediate inhibition. GABAARs are comprised of 5 subunits. Two of these are α and two are β subunits. The fifth is usually γ2 or δ. Although the fifth is not required for gating, in recombinant receptors the presence of the γ2 or δ subunit dramatically alters biophysical and pharmacological properties. In native cells, the fifth subunit is thought to mark specific roles in tonic (δ subunit) and phasic (γ2 subunit) inhibition. We do not understand the physiological contributions of receptor subclasses defined by these subunits, although emerging evidence suggests that receptor subclasses have distinct roles in mental functions, and therapeutic drugs target one or the other subclass to produce different psychoactive effects. For instance, neurosteroids, which may have δ-selective actions, are emerging antidepressants. No antagonist exists to separate δ receptors from γ2 receptors, so many questions about their respective contributions remain. We were compelled by the shortcomings of previous approaches and the historical advantages of selective antagonism to create mouse lines with a point mutation in either γ2 or δ, which endows resistance to the non-competitive GABAAR antagonist picrotoxin. Preliminary data show the potential utility of these tools. Here, we test the overarching hypothesis that δ receptors mediate δ-driven disinhibition in cortical areas including the hippocampus. We will explore the role of δ receptors in cell classes known to express δ and that may offer a substrate for δ-driven disinhibition. Finally, we will test the impact of δ receptors in circuits of the hippocampus and thalamus important for neuropsychiatric illness, with the hypothesis that δ-driven disinhibition drives γ oscillations responsible for aspects of cognition, and δ receptors separately drive sleep spindles in thalamocortical circuits. Our recent results have already altered prevailing views and allow us to interrogate roles of receptor subpopulations in cellular and network function. Our approach will guide rational drug development aimed at inhibition.