Functional role of vesicular zinc in synaptic mechanisms in the amygdala

囊泡锌在杏仁核突触机制中的功能作用

• 批准号: 7890769
• 负责人: VADIM BOLSHAKOV
• 金额: $ 7.9万
• 依托单位: MCLEAN HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-22 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7890769
• 关键词: Ablation; Affect; Affinity; Amygdaloid structure; Anxiety; Area; Auditory; Auditory area; Behavior; Biological Assay; Biological Models; Brain; Cell Nucleus; Cells; Chelating Agents; Complex; Conditioned Stimulus; Development; Disease; Fright; Genes; Glutamates; Knock-out; Knockout Mice; Knowledge; Lateral; Learning; Link; Long-Term Potentiation; Membrane; Memory; Methods; Mus; N-Methyl-D-Aspartate Receptors; Nerve; Neural Pathways; Neurons; Patch-Clamp Techniques; Pathway interactions; Physiology; Post-Traumatic Stress Disorders; Process; Regulation; Role; Slice; Synapses; Synaptic Transmission; Synaptic Vesicles; Synaptic plasticity; System; Thalamic structure; Time; Vesicle; Zinc; Zinc deficiency; base; conditioned fear; improved; interest; neurotransmission; novel therapeutics; patch clamp; postsynaptic; presynaptic; public health relevance; research study; response; synaptic function; therapeutic development; zinc-binding protein

DESCRIPTION (provided by applicant): The objective of this proposal is to establish and characterize the functional role of synaptically-releasable zinc, contained in synaptic vesicles (vesicular zinc), at glutamatergic synapses of the amygdala circuitry implicated in auditory fear conditioning. Our recent findings indicate that zinc transporter-3 (ZnT-3), serving as a marker for zinc-containing neurons, is expressed in the lateral amygdala and the TE3 area of the auditory cortex, conveying the auditory conditioned stimulus (CS) information to the lateral nucleus of the amygdala (LA) during fear conditioning, thus suggesting a potential role for vesicular zinc in regulation of synaptic functions in fear conditioning pathways. Results of our experiments with Zn2+ chelators imply that vesicular Zn2+ can control the induction of spike timing-dependent long-term potentiation (LTP) at cortico-amygdala synapses. We now propose a detailed electrophysiological analysis of the role of vesicular Zn2+, releasable in the course of synaptic activation, in synaptic transmission and plasticity in cortical and thalamic inputs to the LA, delivering auditory CS information to the amygdala during fear conditioning, in slices from ZnT-3 knockout and control mice. These genetically modified mice with targeted disruption of the ZnT-3 gene lack vesicular zinc. Both the compound and unitary postsynaptic responses will be recorded with whole-cell patch-clamp techniques and analyzed to estimate the effects of ZnT3 ablation on synaptic transmission and plasticity in the amygdala. We will also explore whether ZnT-3 knockout mice compensate for the lack of vesicular zinc by decreased GABAergic inhibition of principal neurons in the LA, assaying inhibitory neurotransmission in slices from control and ZnT-3 knockout mice. Our hypothesis is that the ability of glutamatergic synapses in fear conditioning pathways to undergo LTP can be controlled by vesicular Zn2+, released at activated synapses during LTP- inducing stimulation. The proposed studies will improve our understanding of the mechanisms of synaptic plasticity which could underlie the acquisition of fear memory. A better knowledge of the cellular mechanisms of fear-related behaviors will permit the rational development of novel therapeutic treatments for posttraumatic stress disorder, generalized anxiety, and other disorders implicating the fear system of the brain. PUBLIC HEALTH RELEVANCE: The proposed studies will improve our understanding of the mechanisms of synaptic plasticity which may underlie the acquisition of fear memory. A better knowledge of the cellular mechanisms of fear-related behaviors will permit the rational development of novel therapeutic treatments for posttraumatic stress disorder, generalized anxiety, and other disorders implicating the fear system of the brain.

描述（由申请人提供）：本提案的目的是建立和表征突触释放锌的功能作用，锌包含在突触囊泡（囊泡锌）中，杏仁核回路的谷氨酸突触与听觉恐惧条件反射有关。我们最近的研究发现，锌转运蛋白-3 （zinc transporter-3, ZnT-3）作为含锌神经元的标记物，在恐惧条件反射过程中在侧杏仁核和听觉皮层TE3区表达，将听觉条件刺激（CS）信息传递到侧杏仁核，从而提示水泡状锌可能在恐惧条件反射通路的突触功能调节中发挥作用。Zn2+螯合剂的实验结果表明，囊泡Zn2+可以控制皮质-杏仁核突触的峰值时间依赖性长期增强（LTP）的诱导。我们现在提出了一个详细的电生理分析，在ZnT-3敲除小鼠和对照小鼠的切片中，在突触激活过程中释放的泡状Zn2+在皮层和丘脑向LA输入的突触传递和可塑性中的作用，在恐惧条件反射期间向杏仁核传递听觉CS信息。这些靶向破坏ZnT-3基因的转基因小鼠缺乏水疱锌。我们将利用全细胞膜片钳技术记录复合和单一突触后反应，并分析ZnT3消融对杏仁核突触传递和可塑性的影响。我们还将探讨ZnT-3基因敲除小鼠是否通过降低LA主要神经元的gaba能抑制来补偿囊状锌的缺乏，并分析对照小鼠和ZnT-3基因敲除小鼠的神经传递抑制。我们的假设是，恐惧调节通路中的谷氨酸突触经历LTP的能力可以由水疱性Zn2+控制，在LTP诱导刺激时，激活的突触释放Zn2+。这些研究将有助于加深我们对突触可塑性机制的理解，这可能是恐惧记忆习得的基础。更好地了解恐惧相关行为的细胞机制将允许合理地开发新的治疗创伤后应激障碍、广泛性焦虑和其他与大脑恐惧系统有关的疾病的治疗方法。