Functional role of vesicular zinc in synaptic mechanisms in the amygdala

描述（由申请人提供）：本提案的目的是确定和表征突触囊泡（囊泡锌）中所含的突触可释放锌在杏仁核回路中与听觉恐惧条件反射有关的突触能突触中的功能作用。我们最近的研究结果表明，锌转运蛋白-3（ZnT-3）作为含锌神经元的标志物，在外侧杏仁核和听觉皮层的TE 3区表达，在恐惧条件反射过程中将听觉条件刺激（CS）信息传递到杏仁核外侧核（LA），因此，提示囊泡锌在调节恐惧条件反射通路中的突触功能中的潜在作用。我们的实验结果与锌+螯合剂意味着，囊泡锌+可以控制的尖峰时间依赖性长时程增强（LTP）在皮质杏仁核突触的诱导。我们现在提出了一个详细的电生理分析的作用，囊泡锌2+，可释放的过程中的突触激活，在突触传递和可塑性的皮层和丘脑输入到LA，提供听觉CS信息的杏仁核在恐惧条件反射，在切片从ZnT-3基因敲除和对照小鼠。这些具有ZnT-3基因靶向破坏的遗传修饰小鼠缺乏囊泡锌。复合和单一的突触后反应都将用全细胞膜片钳技术记录并分析，以估计ZnT 3消融对杏仁核中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中主要神经元的GABA能抑制来补偿囊泡锌的缺乏，测定来自对照和ZnT-3基因敲除小鼠的切片中的抑制性神经传递。我们的假设是，在恐惧条件反射通路中，突触能经历LTP的能力可以由囊泡Zn 2+控制，在LTP诱导刺激期间，在激活的突触处释放。这些研究将有助于我们更好地理解恐惧记忆获得的突触可塑性机制。更好地了解恐惧相关行为的细胞机制将允许合理开发创伤后应激障碍，广泛性焦虑症和其他涉及大脑恐惧系统的疾病的新治疗方法。 公共卫生相关性：这些研究将有助于我们更好地理解恐惧记忆获得的突触可塑性机制。更好地了解恐惧相关行为的细胞机制将允许合理开发创伤后应激障碍，广泛性焦虑症和其他涉及大脑恐惧系统的疾病的新治疗方法。

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.