Early Life Experience Shapes Visceral Circuits

描述（由申请人提供）：早期的生活经历可以改变成人的情绪和压力反应，但只有有限的研究调查了经验如何塑造中枢神经回路的发展。我们预测，对早期生活经历的操纵将改变中枢内脏回路的功能组织，并且改变的神经解剖学将与改变的行为、生理和神经对压力事件的反应相对应。拟议的研究将通过对成年雄性和雌性大鼠进行实验来验证这一预测，这些大鼠的发育历史是在出生后的前两周内每天短暂地与母亲分离15分钟（MS15）或3小时（MS180）。未分离（MS0）大鼠作为对照。作为年轻的成年鼠，所有的大鼠将被筛选在高加迷宫中的行为差异，并收集血液样本以记录约束应激引起的血浆皮质酮的偏离。目标1和目标2中的后续实验将在经过行为和激素筛选的成年大鼠中进行。目的1实验将验证早期产妇护理（通过MS15和MS180操纵）与性别相互作用以不同方式改变中央内脏回路解剖特征的假设。伪狂犬病毒的逆行跨神经元转运将用于探索不同发育历史大鼠中枢自主神经回路的差异。在第二个实验中，将检查去甲肾上腺素能（NA）感觉通路的经验依赖性改变。为此，一种独特的慢病毒载体在多巴胺β羟化酶启动子的控制下表达增强的绿色荧光蛋白，将被微注射到尾端髓质中，以标记投射到下丘脑和边缘前脑的转染NA神经元的轴突。目的2实验将验证早期产妇护理与性别相互作用以差异改变应激源诱导的中枢内脏回路节点神经Fos激活的假设。大鼠将在受限、氯化锂处理、捕食者气味暴露或匹配的对照处理后灌注固定液，以分析刺激诱导的髓质NA神经元及其中央投射野的Fos表达。NA末端免疫标记密度和CRF/CRH标记也将被量化，以确定性别和/或MS组差异是否相互作用。将根据筛查试验中的行为和激素反应对数据进行分析和解释，并注意预测产后早期经历和性别对解剖和生理结果的影响。这项工作将促进我们对早期产妇护理如何改变男性和女性中枢内脏回路发育轨迹的理解，并将为早期经历对成年情绪和应激反应的影响提供新的见解。婴儿与其母亲（或主要照顾者）之间的相互作用对正常生长发育至关重要，干扰会破坏后代的生理和行为功能。拟议的研究将在大鼠身上使用解剖学和生理学方法来验证这样一种假设，即早期生活事件对后来对压力和情绪事件的反应的影响与向大脑提供内脏感觉反馈并产生情绪表达的回路的发育可塑性有关。

DESCRIPTION (provided by applicant): Early life experience can alter adult emotionality and stress responsiveness, but only limited research has examined how experience shapes the development of central neural circuits. We predict that manipulation of early life experience will alter the functional organization of central visceral circuits, and that altered neuroanatomy will correspond with altered behavioral, physiological, and neural responses to stressful events. The proposed research will test this prediction by performing experiments in adult male and female rats with a developmental history of having been handled briefly for daily maternal separation of either 15 min (MS15) or 3 hr (MS180) during the first two postnatal weeks. Non-separated (MS0) rats will serve as controls. As young adults, all rats will be screened for behavioral differences in the elevated plus maze, and blood samples will be collected to document restraint stress-evoked excursions in plasma corticosterone. Subsequent experiments in Aims 1 and 2 will be performed in behaviorally- and hormonally-screened adult rats. Aim 1 experiments will test the hypothesis that early maternal care (manipulated via MS15 and MS180) interacts with sex to differentially alter the anatomical features of central visceral circuits. Retrograde transneuronal transport of pseudorabies virus will be used to probe for differences in central autonomic circuits in rats with different developmental histories. In the second experiment, experience-dependent alterations in noradrenergic (NA) sensory pathways will be examined. For this, a unique lentivirus vector that expresses enhanced green fluorescent protein under the control of a dopamine beta hydroxylase promoter will be microinjected into the caudal medulla to label the axonal arbors of transfected NA neurons that project to the hypothalamus and limbic forebrain. Aim 2 experiments will test the hypothesis that early maternal care interacts with sex to differentially alter stressor-induced neural Fos activation in central visceral circuit nodes. Rats will be perfused with fixative after restraint, LiCl treatment, predator odor exposure, or matched control treatment for analyses of stimulus-induced Fos expression in medullary NA neurons and in their central projection fields. NA terminal immunolabeling density and CRF/CRH labeling also will be quantified to determine whether sex and/or MS group differences interact. Data will be analyzed and interpreted within the context of behavioral and hormonal responses in the screening tests, with attention paid to predicted effects of early postnatal experience and sex on anatomical and physiological outcomes. The proposed work will advance our understanding of how early maternal care can alter the developmental trajectory of central visceral circuits in males and females, and will provide new insights regarding the impact of early experience on adult emotionality and stress responsiveness. Interactions between infants and their mother (or primary caregiver) are critical for normal growth and development, and perturbations can disrupt physiological and behavioral functions in the offspring. The proposed research will use anatomical and physiological methods in rats to test the hypothesis that the influence of early life events on later responses to stress and emotional events is linked to developmental plasticity of circuits that provide visceral sensory feedback to the brain and generate emotional expression.