Signaling mediated by the neurotrophin receptor, TrkB, has been implicated in diverse psychiatric and neurological disorders. Notably, TrkB is activated during and is required for limbic epileptogenesis. During the current funding period, we discovered a downstream signaling pathway by which TrkB activation promotes limbic epileptogenesis in the kindling model in vivo, namely the PLC31 pathway. In vitro studies demonstrate that TrkB-mediated PLC31 signaling promotes reduced expression of the K-Cl co-transporter, KCC2, resulting in accumulation of intracellular chloride ([Cl-]i), a shift of EGABA in a depolarizing direction, and potentially impaired synaptic inhibition. Direct study of human epileptic tissue advances reduced expression of KCC2 and the resulting accumulation of [Cl-]i as an important mechanism contributing to the hyperexcitability of limbic epilepsy. These findings underscore the importance of elucidating the signaling pathways operative in animal models in vivo that reduce KCC2 expression. We hypothesize that TrkB- mediated activation of PLC31 mediates the reduced KCC2 expression in limbic epileptogenesis in vivo and promotes limbic epileptogenesis. We will test these hypotheses with biochemical, immunohistochemical, electrophysiological, and imaging methods focused on wild type (WT) and genetically modified mice in vivo and ex vivo. Insight into the signaling pathways downstream from TrkB that promote limbic epileptogenesis promises to facilitate development of specific and novel therapies while simultaneously shedding light on the underlying cellular mechanisms.

Public Health Relevance

Limbic epilepsy is a common and frequently devastating neurological disorder. Successful completion of this project will provide information useful for the development of novel therapeutics aimed at preventing the development and/or progression of this disorder.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
Project #
Application #
Study Section
Clinical Neuroplasticity and Neurotransmitters Study Section (CNNT)
Program Officer
Whittemore, Vicky R
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Duke University
Schools of Medicine
United States
Zip Code
Dingledine, Raymond; Coulter, Douglas A; Fritsch, Brita et al. (2017) Transcriptional profile of hippocampal dentate granule cells in four rat epilepsy models. Sci Data 4:170061
Hedrick, Nathan G; Harward, Stephen C; Hall, Charles E et al. (2016) Rho GTPase complementation underlies BDNF-dependent homo- and heterosynaptic plasticity. Nature 538:104-108
Harward, Stephen C; Hedrick, Nathan G; Hall, Charles E et al. (2016) Autocrine BDNF-TrkB signalling within a single dendritic spine. Nature 538:99-103
Puranam, Ram S; He, Xiao Ping; Yao, Lijun et al. (2015) Disruption of Fgf13 causes synaptic excitatory-inhibitory imbalance and genetic epilepsy and febrile seizures plus. J Neurosci 35:8866-81
Gu, Bin; Huang, Yang Zhong; He, Xiao-Ping et al. (2015) A Peptide Uncoupling BDNF Receptor TrkB from Phospholipase C?1 Prevents Epilepsy Induced by Status Epilepticus. Neuron 88:484-91
Harward, Stephen C; McNamara, James O (2014) Aligning animal models with clinical epilepsy: where to begin? Adv Exp Med Biol 813:243-51
Liu, Gumei; Kotloski, Robert J; McNamara, James O (2014) Antiseizure effects of TrkB kinase inhibition. Epilepsia 55:1264-73
Helgager, Jeffrey; Huang, Yang Zhong; Mcnamara, James O (2014) Brain-derived neurotrophic factor but not vesicular zinc promotes TrkB activation within mossy fibers of mouse hippocampus in vivo. J Comp Neurol 522:3885-99
He, Xiao Ping; Wen, Renren; McNamara, James O (2014) Impairment of kindling development in phospholipase C?1 heterozygous mice. Epilepsia 55:456-63
Wang, Hong-Gang; He, Xiao Ping; Li, Qiang et al. (2013) The auxiliary subunit KChIP2 is an essential regulator of homeostatic excitability. J Biol Chem 288:13258-68

Showing the most recent 10 out of 27 publications