Sexually Dimorphic Amygdala Dysfunction in a Mouse Model of Global Cerebral Ischemia

项目摘要/摘要 虽然复苏科学的进步提高了心脏骤停的存活率，但我们缺乏改善的治疗方法。 这一患者群体的认知-情感结局。我们的实验室之前已经发现认知功能障碍 海马神经变性所致全脑缺血小鼠模型的建立 并损害海马区的可塑性。然而，还没有研究试图确定杏仁核功能障碍 GCI，尽管有临床证据表明存在情绪障碍，如焦虑和创伤后应激障碍 (创伤后应激障碍)。因此，重要的是要确定GCI对杏仁核的影响，杏仁核是大脑的情绪中枢。 大脑。我们的实验室有一个成熟的、可翻译的GCI小鼠模型，即心脏骤停/心肺 复苏模型(CA/CPR)，在评估GCI后杏仁核功能方面发挥了重要作用。我有过 利用杏仁核依赖的延迟-恐惧条件反射(DFC)范式评估联想学习和 记忆，并在两个回路中进行了场兴奋性突触后电位(FEPSP)的记录 杏仁核，作为衡量杏仁核功能的指标。我发现了一种性二型性缺陷和回路特异性缺陷 GCI后杏仁核功能，我正在努力确定这种功能障碍的机制。我找到了 在杏仁核依赖的联想学习中存在男性特有的损伤和伴随的缺陷 杏仁基底外侧核皮质传入的长时程增强(LTP)。我也没有发现任何证据 杏仁核功能的这些缺陷可以归因于杏仁核内的神经退化。我有过 验证了两个电路之间存在LTP诱导的不同机制，并且这种差异具有 导致了我在这项提议中提出的假设的发展。不同的是，大脑皮层输入的LTP 血乳酸需要功能性的N-甲基-D-天冬氨酸受体和L型钙通道(LTCC)，而体内的 杏仁核回路只需要功能正常的NMDA受体。因此，我假设GCI导致脑功能障碍。 LTCC在雄性小鼠的BLA内，从而导致杏仁核依赖行为的缺陷，并 LTP。为了验证这一假设，我分离并记录了BLA锥体的LTCC介导的电流 神经元。这种方法虽然有效，但在CA/CPR和假动物之间没有显著差异。 然而，该方法的一个警告是，只有体细胞和体周LTCC可以被测量。因此，要 充分评估我的假设，我提出了更多针对特定地点的实验，以评估其贡献 LTCC在单个远端树突棘的突触传递。我将使用双光子钙成像技术 BLA中的单个脊椎，同时电诱导皮质输入到BLA的LTP。然后我将使用 药理学以确定钙反应的LTCC成分并比较Sham和 CA/CPR动物。

Project Summary/Abstract While advances in resuscitation science have improved cardiac arrest survival, we lack therapies to improve cognitive-affective outcomes in this patient population. Our lab has previously identified cognitive dysfunction in a mouse model of global cerebral ischemia (GCI) which has been attributed to hippocampal neurodegeneration and impaired hippocampal plasticity. However, no study has attempted to identify amygdala dysfunction after GCI, despite clinical evidence of emotional dysfunction, such as anxiety and Post-Traumatic Stress Disorder (PTSD). Therefore, it is important to identify the effect that GCI has on the amygdala, the emotional center of the brain. Our lab has a well-developed, translatable mouse model of GCI, the cardiac arrest/cardiopulmonary resuscitation model (CA/CPR), that has been instrumental in assessing amygdala function after GCI. I have utilized the amygdala-dependent delay-fear conditioning (DFC) paradigm to assess associative learning and memory and have performed field excitatory post-synaptic potential (fEPSP) recordings in two circuits within the amygdala, as measures of amygdala function. I have found a sexually dimorphic and circuit specific deficit in amygdala function after GCI and am working toward identifying the mechanism of this dysfunction. I have found that there is a male specific impairment in amygdala-dependent associative learning and a concomitant deficit of long-term potentiation (LTP) in the cortical input to the basolateral amygdala. I have also found no evidence that these deficits of amygdala function can be attributed to neurodegeneration within the amygdala. I have verified that there are differential mechanisms of LTP induction between the two circuits and this difference has led to the development of my hypothesis put forth in this proposal. The difference being, LTP of the cortical input to the BLA requires functional NMDA receptors and L-type calcium channels (LTCCs), whereas the intra amygdala circuit only requires functional NMDA receptors. Thus, I hypothesize that GCI induces dysfunction of LTCC's within the BLA of male mice, thereby contributing to the deficits in amygdala-dependent behavior and LTP. To assess this hypothesis, I have isolated and recorded LTCC mediated currents from BLA pyramidal neurons. This method, while powerful, has yielded no significant difference between CA/CPR and sham animals. However, a caveat of the method is that only somatic and peri somatic LTCCs can be measured. Therefore, to fully evaluate my hypothesis, I have proposed more site-specific experiments that will evaluate the contribution of LTCC's to synaptic transmission at individual distal dendritic spines. I will use two-photon calcium imaging of individual spines in the BLA while electrically inducing LTP of the cortical input to the BLA. I will then use pharmacology to identify the LTCC component of the calcium response and compare between sham and CA/CPR animals.