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Changes in mACh, NMDA and GABA A receptor binding after lateral fluid‐percussion injury: in vitro autoradiography of rat brain frozen sections
Author(s) -
Sihver Sven,
Marklund Niklas,
Hillered Lars,
Långström Bengt,
Watanabe Yasuyoshi,
Bergström Mats
Publication year - 2001
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2001.00428.x
Subject(s) - hippocampus , dizocilpine , cortex (anatomy) , nmda receptor , medicine , flumazenil , glutamate receptor , endocrinology , temporal cortex , traumatic brain injury , chemistry , anesthesia , receptor , neuroscience , gabaa receptor , biology , psychiatry
Adult rats were subjected to a moderate lateral fluid percussion injury (FPI), followed by survival periods of 2 and 12 h. Regional NMDA subtype glutamate, muscarinic acetylcholine and GABA A receptor binding in various brain regions was analysed by quantitative in vitro autoradiography and short‐lived positron emission tomography tracers [ 11 C]cyano‐dizocilpine, 4‐ N ‐[ 11 C]methylpiperidylbenzilate (4‐ N ‐[ 11 C]MPB), and [ 11 C]flumazenil, respectively. The binding potential (BP, B max / K D ) was calculated. The data with [ 11 C]cyano‐dizocilpine showed a significant decrease in BP bilaterally for the frontoparietal cortex and hippocampus at both time points, in comparison with that of the sham‐operated controls. At 12 h the decrease was significantly more prominent for the ipsilateral cortex and hippocampus than for the contralateral side. The BP of 4‐ N ‐[ 11 C]MPB was significantly decreased after 2 h for the trauma‐side hippocampus, and after 12 h it had decreased for the trauma‐site cortex and the bilateral hippocampus. The [ 11 C]flumazenil exhibited a significant decrease in BP for the trauma‐site cortex and the underlying hippocampus by 2 h after the traumatic brain injury. After 12 h a significantly decreased BP was observed only for the trauma‐site cortex. The finding of a decreased BP demonstrates the involvement of these receptor systems in the development of cellular dysfunction, which is widespread and not limited to the site of lateral FPI.