caa a22 4500 465767206 CHVBK 20180323111917.0 cr unu---uuuuu 170327e19900101xx s 000 0 eng 10.1007/BF00308717 doi (NATIONALLICENCE)springer-10.1007/BF00308717 Electron microscopic study of the gerbil dentate gyrus after transient forebrain ischemia [Elektronische Daten] [B. Crain, D. Evenson, K. Polsky, J. Nadler] Summary: Silver impregnation performed 1-2 days after transient forebrain ischemia in the Mongolian gerbil demonstrated terminal-like granular deposits in the outer two-thirds of the hippocampal dentate molecular layer (perforant path terminal zone), even though neither the cell bodies of origin of the perforant path nor the dentate granule cells were destroyed. Electron microscopic studies of the dentate gyrus were performed in an effort to discover the identity of these degenerating structures. Electron microscopy revealed that the granular silver deposits corresponded to electron-dense profiles. Many of these were degenerating boutons and some were degenerating postsynaptic dendritic fragments, but most of them could not be identified with certainty. Electron-dense profiles were less numerous than expected from the density of granular silver deposits. These structures were probably the degenerating axons, axon terminals and dendrites of CA4 neurons. The granular silver deposits and electron-dense boutons observed in the inner third of the dentate molecular layer 5 days after transient ischemia can probably be explained by the ischemia-induced degeneration of CA4 mossy cells, which give rise to the dentate associational-commissural projection. Finally, most mossy fiber boutons in area CA4 and some boutons in the molecular layer appeared watery and enlarged on postischemia days 1 and 2. Mossy fiber boutons with this ultrastructural appearance have previously been observed in seizure-prone animals and in animals undergoing convulsant-induced seizures. Although no postischemic seizures occur under the conditions of this study, these findings support the idea that excitatory pathways become hyperactive after transient ischemia. Springer-Verlag, 1990 Cerebral ischemia nationallicence Hippocampus nationallicence Dentate gyrus nationallicence Perforant path nationallicence Electron-dense degeneration nationallicence Crain B. Department of Pathology, Duke University Medical Center, Box 3712, 27710, Durham, NC, USA aut Evenson D. Department of Pharmacology, Duke University Medical Center, Box 3712, 27710, Durham, NC, USA aut Polsky K. Department of Pathology, Duke University Medical Center, Box 3712, 27710, Durham, NC, USA aut Nadler J. Department of Neurobiology, Duke University Medical Center, Box 3712, 27710, Durham, NC, USA aut Acta Neuropathologica Springer-Verlag 79/4(1990-01-01), 409-417 0001-6322 79:4<409 1990 79 401 https://doi.org/10.1007/BF00308717 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00308717 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Crain B. Department of Pathology, Duke University Medical Center, Box 3712, 27710, Durham, NC, USA aut NATIONALLICENCE 700 1- Evenson D. Department of Pharmacology, Duke University Medical Center, Box 3712, 27710, Durham, NC, USA aut NATIONALLICENCE 700 1- Polsky K. Department of Pathology, Duke University Medical Center, Box 3712, 27710, Durham, NC, USA aut NATIONALLICENCE 700 1- Nadler J. Department of Neurobiology, Duke University Medical Center, Box 3712, 27710, Durham, NC, USA aut NATIONALLICENCE 773 0- Acta Neuropathologica Springer-Verlag 79/4(1990-01-01), 409-417 0001-6322 79:4<409 1990 79 401 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer