Brain injury is a leading cause of moratlity and morbidity among young people in the industrialized world. Attempts to treat accidental brain injuries with glutamate NMDA receptor (NMDAR) antagonists have failed to.produce any improvement in outcome in several major clinical trials. These trials were predicated on the hypothesis that neurological deficits after head injury are, at least in part, the result of hyperactivation of NMDAR and """"""""excitotoxicity"""""""". The working hypothesis behind the proposed studies is three fold: 1. Hyperactivation of NMDAR after head injury is short lived and gives way to prolonged hypofunction; 2. The cognitive deficits after brain injury are a results of underactivation, rather than overactivation, of NMDA receptors. 3. Delayed activation of NMDAR may accelerate recovery of function after brain injury. A secondary hypothesis postulates that some brain regions;such as the hippocampus;are inherently more vulnerable to brain injury than others. We propose to test these hypotheses in mice with closed head injury;an animal model of blunt head trauma. Regional changes in NMDAR availablility and functional (activational) state will be measured at times ranging from 5 min to 60 days after injury using quantitative autoradiography of the use-dependent ligand MK801. Physiological correlates of NMDAR hyepr-activation and hypo-activation will be measured using electrophysiology (Long term potentiation). Cognitive deficits will be tested 14 and 60 days after the injury using two different tasks;the object recognition test and the Morris water maze in animals administered with the full agonist NMDA , the partial NMDAR agonist d-Cycloserine or the antagonist MK801 at various time points and frequencies after the injury. Finally the contribution of several likely mechanisms to the dynamic changes in NMDAR after brain injury will be investigated by 1. Dose response and kinetic studies of the relationship between dose and duration of NMDAR activation and functional respone 2. Manipulating assay conditions 3. immuno-histochemical staining for the obligatory NR1 unit and the NR2 subunits of NMDAR. The proposed research focuses on the fate of NMDAR, a molecule believed to play a key role in the pathology of brain injury. Brain injury is a major public health problem since it is associated with death and long-term disability in a significant proportion of victims, who are mostly young adults. The results may explain the failure of NMDAR antagonists in clinical trials and suggest novel strategies for treatment of brain injury.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS050285-04
Application #
7738481
Study Section
Clinical Neuroscience and Disease Study Section (CND)
Program Officer
Hicks, Ramona R
Project Start
2007-02-06
Project End
2011-11-30
Budget Start
2009-12-01
Budget End
2010-11-30
Support Year
4
Fiscal Year
2010
Total Cost
$370,560
Indirect Cost
Name
Brookhaven National Laboratory
Department
Type
DUNS #
027579460
City
Upton
State
NY
Country
United States
Zip Code
11973
Shohami, Esther; Biegon, Anat (2014) Novel approach to the role of NMDA receptors in traumatic brain injury. CNS Neurol Disord Drug Targets 13:567-73
Pareto, Deborah; Biegon, Anat; Alexoff, David et al. (2013) In vivo imaging of brain aromatase in female baboons: [11C]vorozole kinetics and effect of the menstrual cycle. Mol Imaging 12:
Grossman, Rachel; Paden, Charles M; Fry, Pamela A et al. (2012) Persistent region-dependent neuroinflammation, NMDA receptor loss and atrophy in an animal model of penetrating brain injury. Future Neurol 7:329-339
Dhawan, Jasbeer; Benveniste, Helene; Luo, Zhongchi et al. (2011) A new look at glutamate and ischemia: NMDA agonist improves long-term functional outcome in a rat model of stroke. Future Neurol 6:823-834
Liraz-Zaltsman, Sigal; Alexandrovich, Alexander G; Trembovler, Victoria et al. (2011) Regional sensitivity to neuroinflammation: in vivo and in vitro studies. Synapse 65:634-42
Biegon, Anat; Kim, Sung Won; Alexoff, David L et al. (2010) Unique distribution of aromatase in the human brain: in vivo studies with PET and [N-methyl-11C]vorozole. Synapse 64:801-7
Adeleye, Amos; Shohami, Esther; Nachman, Dean et al. (2010) D-cycloserine improves functional outcome after traumatic brain injury with wide therapeutic window. Eur J Pharmacol 629:25-30
Dhawan, Jasbeer; Benveniste, Helene; Nawrocky, Marta et al. (2010) Transient focal ischemia results in persistent and widespread neuroinflammation and loss of glutamate NMDA receptors. Neuroimage 51:599-605
Biegon, Anat; Kim, Sung-Won; Logan, Jean et al. (2010) Nicotine blocks brain estrogen synthase (aromatase): in vivo positron emission tomography studies in female baboons. Biol Psychiatry 67:774-7
Hirshler, Yafit Kuttner; Polat, Uri; Biegon, Anat (2010) Intracranial electrode implantation produces regional neuroinflammation and memory deficits in rats. Exp Neurol 222:42-50

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