The current proposal focuses on mechanisms and consequences of early-life seizures that are provoked by proconvulsant'stressors' such as fever (hyperthermia) and hypoxia. These non-genetic 'triggered' seizures constitute the majority of developmental seizures. While the outcome of simple febrile seizures is generally benign, and the outcome of many developmental seizures depends on their etiology, emerging evidence in both human and animals indicates that prolonged febrile seizures and recurrent triggered seizures may be associated with neuronal injury. The applicant has demonstrated that the stress-activated neuropeptide, corticotropin releasing hormone (CRH), a well established key mediator of the CNS stress-response, acts as a powerful, age-specific convulsant in the developing brain and promotes injury of hippocampal neurons. Thus, CRH may play a role in the mechanisms by which triggered developmental seizures influence neuronal integrity. During the recent funding period, the applicant established the presence of a significant population of CRH-expressing interneurons in the developing hippocampus and the mechanisms by which CRH interacts with glutamate receptor activation to enhance hippocampal excitability. In addition, recent findings suggest that (1 ) pro-convulsant stressors may increase CRH expression in limbic regions and (2) excessive CRH-receptor activation during early-life may result in significant long-term consequences on hippocampal integrity and function. Therefore, the proposed research tests the hypothesis that proconvulsant stressors increase CRH levels in hippocampus resulting in augmentation by the peptide of excitotoxic mechanisms. to enhance neuronal injury and lead to long-term hippocampal dysfunction. Four experiments are proposed to test this hypothesis: 1 ) studying-using in situ hybridization and immunocytochemistry- whether proconvulsant stressors enhance CRH-expression and levels in hippocampus. Studying the unique mechanisms by which CRH leads to hippocampal neuronal death using (2) in vivo and (3) in vitro dissociated hippocampal cell approaches, and, 4) Examining the significant long-term consequences of excessive CRH-dependent excitation during early life, focusing on hippocampal neuronal loss and hippocampal-dependent cognitive dysfunction. The significance of the proposed studies derives from their focus on mechanisms and consequences of early life provoked seizures that constitute the majority of developmental seizures, but remain relatively unstudied. The proposed studies, delineating age-specific mechanisms for seizure-related neuronal injury and its consequences should lead to the development of novel, age-appropriate, specific therapies to prevent these consequences.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS028912-10
Application #
6639424
Study Section
Special Emphasis Panel (ZRG1-BDCN-5 (01))
Program Officer
Fureman, Brandy E
Project Start
1992-03-01
Project End
2005-02-28
Budget Start
2003-07-01
Budget End
2005-02-28
Support Year
10
Fiscal Year
2003
Total Cost
$300,800
Indirect Cost
Name
University of California Irvine
Department
Type
Schools of Medicine
DUNS #
046705849
City
Irvine
State
CA
Country
United States
Zip Code
92697
Gunn, Benjamin G; Sanchez, Gissell A; Lynch, Gary et al. (2018) Hyper-diversity of CRH interneurons in mouse hippocampus. Brain Struct Funct :
Singh-Taylor, A; Molet, J; Jiang, S et al. (2018) NRSF-dependent epigenetic mechanisms contribute to programming of stress-sensitive neurons by neonatal experience, promoting resilience. Mol Psychiatry 23:648-657
Sandman, Curt A; Curran, Megan M; Davis, Elysia Poggi et al. (2018) Cortical Thinning and Neuropsychiatric Outcomes in Children Exposed to Prenatal Adversity: A Role for Placental CRH? Am J Psychiatry 175:471-479
Bolton, Jessica L; Molet, Jenny; Regev, Limor et al. (2018) Anhedonia Following Early-Life Adversity Involves Aberrant Interaction of Reward and Anxiety Circuits and Is Reversed by Partial Silencing of Amygdala Corticotropin-Releasing Hormone Gene. Biol Psychiatry 83:137-147
Walker, Claire-Dominique; Bath, Kevin G; Joels, Marian et al. (2017) Chronic early life stress induced by limited bedding and nesting (LBN) material in rodents: critical considerations of methodology, outcomes and translational potential. Stress 20:421-448
Gunn, B G; Baram, T Z (2017) Stress and Seizures: Space, Time and Hippocampal Circuits. Trends Neurosci 40:667-679
Curran, Megan M; Sandman, Curt A; Poggi Davis, Elysia et al. (2017) Abnormal dendritic maturation of developing cortical neurons exposed to corticotropin releasing hormone (CRH): Insights into effects of prenatal adversity? PLoS One 12:e0180311
Molet, J; Heins, K; Zhuo, X et al. (2016) Fragmentation and high entropy of neonatal experience predict adolescent emotional outcome. Transl Psychiatry 6:e702
Chen, Yuncai; Molet, Jenny; Lauterborn, Julie C et al. (2016) Converging, Synergistic Actions of Multiple Stress Hormones Mediate Enduring Memory Impairments after Acute Simultaneous Stresses. J Neurosci 36:11295-11307
Molet, Jenny; Maras, Pamela M; Kinney-Lang, Eli et al. (2016) MRI uncovers disrupted hippocampal microstructure that underlies memory impairments after early-life adversity. Hippocampus 26:1618-1632

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