CaV2.2 splice variants in the hippocampus: function and pharmacology

大麻素的影响是多种多样的，而且依赖于剂量。例如，低剂量会产生焦虑症 然而，高剂量会导致焦虑；在记忆和认知方面也有类似的影响。然而， 造成这种情况的原因尚不清楚。在突触水平，已知大麻素受体1(CB1R)影响 通过抑制突触前钙通道释放递质，包括N型(Cav2.2)通道 它们在连接神经元活动和海马区递质释放(HPC)方面起着至关重要的作用。这个大脑 区域对于情绪处理和学习很重要，而Cav2.2通道在大脑中研究最深入的回路之一中是必不可少的。我们的长期目标是破译Cav2.2频道的调节和功能，网址为 特定的HPC突触告知HPC活动的基本机制，并使基于CB1R的新疗法成为可能 发信号。 选择性剪接是一种细胞特异性机制，影响Cav2.2通道的功能和调节。 外显子18a的剪接产生+18a-Cav2.2和D18a-Cav2.2剪接变体。中国的神经传递 表达+18a-Cav2.2变体的突触显示递质释放的可能性增加，而 CB1R激动剂与表达+18a-Cav2.2变体的激动剂相比，但潜在的 机制尚不清楚。+18-Cav2.2剪接变异体含有21个氨基酸插入区域 与释放机械相互作用。我们的中心假设是+18a-Cav2.2剪接变异体增强递质 通过与SNARE蛋白的差异相互作用，释放和阻止CB1R对神经传递的抑制。至 对此进行测试，我们将使用具有受限拼接选择的经验证的鼠标型号(仅+18a或仅18a)和 重组酶标记HPC中的特定神经元用于急性脑片电生理和生化 用于评估蛋白质相互作用的实验。该项目的具体目标是：1)确定功能影响 HPC中+18a-Cav2.2和D18a-Cav2.2剪接变异体在递质释放上的作用，以及2)确定 +18a-Cav2.2和D18a-Cav2.2剪接变体对高性能计算机中发射机释放的CB1R调制。结果是 这个项目也有望提供对海马体功能的基本机制的洞察。 因为大麻素的相互矛盾的影响。新型细胞特异性CB1R信号效应器可以积极地 大麻素类药物的影响研究进展

The effects of cannabinoids are diverse and dose dependent. For instance, low doses produce anxiolysis whereas high doses induce anxiety; similar effects have been seen on memory and cognition. However, the reasons for this are not clear. At the synapse level, the cannabinoid receptor 1 (CB1R) is known to impact transmitter release through inhibition of presynaptic calcium channels, including the N-type (CaV2.2) channels that are paramount in coupling neuronal activity to transmitter release in the hippocampus (HPC). This brain area is important for emotional processing and learning, and CaV2.2 channels are essential in one of the best-studied circuits in the brain. Our long-term goal is to decipher the regulation and function of CaV2.2 channels at specific HPC synapses to inform basic mechanisms of HPC activity, and enable novel therapies based on CB1R signaling. Alternative splicing is a cell-specific mechanism that impacts the function and regulation of CaV2.2 channels. Splicing of exon 18a generates the +18a-CaV2.2 and D18a-CaV2.2 splice variants. Neurotransmission in synapses that express +18a-CaV2.2 variants exhibit enhanced probability of transmitter release, and reduced modulation by CB1R agonists compared to those that express the +18a-CaV2.2 variants, but the underlying mechanisms are unknown. +18-CaV2.2 splice variants contain a 21 aminoacid insertion in the region that interacts with the release machinery. Our central hypothesis is +18a-CaV2.2 splice variants enhance transmitter release and prevent CB1R inhibition of neurotransmission via differential interaction with SNARE proteins. To test this, we will use validated mouse models with restricted splice choice (+18a-only or 18a-only) and recombinase-based labeling of specific neurons in HPC for electrophysiology in acute slices, and biochemical assays to evaluate protein interaction. The specific aims of the project are: 1) To determine the functional impact of +18a-CaV2.2 and D18a-CaV2.2 splice variants on transmitter release in HPC, and 2) To determine the role of +18a-CaV2.2 and D18a-CaV2.2 splice variants on CB1R modulation of transmitter release in HPC. The results of this project are expected to provide insights into the basic mechanisms underlying hippocampal function, as well for the contradictory effects of cannabinoids. Novel cell-specific effectors of CB1R signaling could positively impact development of cannabinoid-based therapeutics