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1208 Increase in fibrinolytic activity and neuronal cell death by kainic acid injection in rat hippocampus
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1206
GLUTAMATE INDUCES RAPID NUCLEAR CHANGES AND A DELAYED CELL DEATH SELECTIVELY IN CA1 NEURONS OF A RAT ORGANOTYPIC HIPPOCAMPAL CULTURE Photon Medical Research Center l, Dept. of Neurosurgery, Hamamatsu University School of Medicine Hamamatsu, 431-31, Japan2 SUSUMU TERAKAWA’, SEIJI YAMAMOT02, TAKASHI SAKURAI’, SHINJI MATSUMURAl We observed with a video microscope that glutamate induces a dramatic nuclear change in primary cultured neurons of the rat. However, it remains unclear whether the same response can be observed in the neurons surrounded by glia as in the brain, because glial cells are highly capable of scavenging glutamate. In this study, we applied the video microscopy to the cultured hippocampal slice of rats, and examined 1) early changes in morphological property of the nucleus exposed to glutamate; and 2) delayed effect of brief application of glutamate. Neurons in the CA1 but not in CA3 region 1) developed granularity of the nuclei within 20 minutes following glutamate (1 mM) exposure; 2) produced tripane-blue-positive cells 48 h later 15 min of glutamate (1 mM) exposure. In conclusion, glutamate induces rapid morphological changes of the nucleus and delayed cell death selectively in the CA1 neurons in the intimate presence of glial cells.
1207
PRODUCTION OF REACTIVE OXYGEN SPECIES AND GLUTAMATE NEUROTOXICITY IN A RAT ORGANOTYPIC HIPPOCAMPAL CULTURE Dpt of Neurosurg., Hamamatsu Univ. School of Med., Hamamatsu, 431-31, Japan’, Photon Medical Res. Center, Hamamatsu Univ. School of Med., Hamamatsu, 431-31, Japan2 SEIJI YAMAMOTO’, SUSUMU TERAKAWA2, TAKASHI SAKURA12, SHINJI MATSUMURA2, KENICHI UEMURAl The fact that antioxidants reduce some types of brain damage mediated by glutamate receptors suggests that reactive oxygen species (ROS) may have a role. In order to determine whether ROS could increase in the event of glutamate neurotoxicity in rat organotypic hippocampal cultures, we observed (1) morphological changes of the neurons in the slice following glutamate (1 mM) exposure under a videoenhanced microscope and (2) production of ROS elicited by glutamate (1 mM) in the cultured slice. Lucigenin is well recognized for its ability to react with ROS, yielding a product that emits chemiluminescence (CL). By measuring lucigenin (300pM)-dependent CL with a photomultiplier, the production of ROS was continuously monitored in the cultured slice. Under a high-resolution microscope we observed rapid nuclear changes of the neurons 10 to 20min after glutamate exposure. However, ROS did not increase but decrease during the same period following exposure to glutamate.
1208
Increase in fibrinolytic hippocampus
activity and neuronal cell death by kainic acid injection in rat
Department of Physiology, Hamamatsu University School of medicine’, Hamamatsu University School of medicine2 NAGAI NOBUO’ , END0 AKIRA’, TAKAHASHI TAKADA YUMIK02, TAKADA AKIKAZU’
HIROSI’,
Department
of Pasophysiology,
IHARA HAYATO’ , URANO TETSUMEP,
Tissue plasminogen activator (tPA) is a secretory serine protease and converts inactive plasminogen to active plasmin. Plasmin then degrades fibrin (fibrinolysis). tPA has been suggested to participate in -neural plasticity and delayed neuronal cell death in central nervous system, yet it’s functions is not clear. To-study the possible function of tPA, we measured tPA antigen, fibrinolytic activity and extracellular proteolysis in rat hippocampus after.lateral cerebroventricle injection of kainic acid (KA) which caused delayed neuronal cell death of hippocampal neurons. KA injection caused increase in tPA antigen and activity, together with an alteration of positive staining pattern in the hippocampus by anti laminin antiserum within 8 hours. These results suggested that increase in extracellular fibrinolytic activity by tPA contribute to neural cell death by KA injection possibly through the alteration of matrix structure.
1206
GLUTAMATE INDUCES RAPID NUCLEAR CHANGES AND A DELAYED CELL DEATH SELECTIVELY IN CA1 NEURONS OF A RAT ORGANOTYPIC HIPPOCAMPAL CULTURE Photon Medical Research Center l, Dept. of Neurosurgery, Hamamatsu University School of Medicine Hamamatsu, 431-31, Japan2 SUSUMU TERAKAWA’, SEIJI YAMAMOT02, TAKASHI SAKURAI’, SHINJI MATSUMURAl We observed with a video microscope that glutamate induces a dramatic nuclear change in primary cultured neurons of the rat. However, it remains unclear whether the same response can be observed in the neurons surrounded by glia as in the brain, because glial cells are highly capable of scavenging glutamate. In this study, we applied the video microscopy to the cultured hippocampal slice of rats, and examined 1) early changes in morphological property of the nucleus exposed to glutamate; and 2) delayed effect of brief application of glutamate. Neurons in the CA1 but not in CA3 region 1) developed granularity of the nuclei within 20 minutes following glutamate (1 mM) exposure; 2) produced tripane-blue-positive cells 48 h later 15 min of glutamate (1 mM) exposure. In conclusion, glutamate induces rapid morphological changes of the nucleus and delayed cell death selectively in the CA1 neurons in the intimate presence of glial cells.
1207
PRODUCTION OF REACTIVE OXYGEN SPECIES AND GLUTAMATE NEUROTOXICITY IN A RAT ORGANOTYPIC HIPPOCAMPAL CULTURE Dpt of Neurosurg., Hamamatsu Univ. School of Med., Hamamatsu, 431-31, Japan’, Photon Medical Res. Center, Hamamatsu Univ. School of Med., Hamamatsu, 431-31, Japan2 SEIJI YAMAMOTO’, SUSUMU TERAKAWA2, TAKASHI SAKURA12, SHINJI MATSUMURA2, KENICHI UEMURAl The fact that antioxidants reduce some types of brain damage mediated by glutamate receptors suggests that reactive oxygen species (ROS) may have a role. In order to determine whether ROS could increase in the event of glutamate neurotoxicity in rat organotypic hippocampal cultures, we observed (1) morphological changes of the neurons in the slice following glutamate (1 mM) exposure under a videoenhanced microscope and (2) production of ROS elicited by glutamate (1 mM) in the cultured slice. Lucigenin is well recognized for its ability to react with ROS, yielding a product that emits chemiluminescence (CL). By measuring lucigenin (300pM)-dependent CL with a photomultiplier, the production of ROS was continuously monitored in the cultured slice. Under a high-resolution microscope we observed rapid nuclear changes of the neurons 10 to 20min after glutamate exposure. However, ROS did not increase but decrease during the same period following exposure to glutamate.
1208
Increase in fibrinolytic hippocampus
activity and neuronal cell death by kainic acid injection in rat
Department of Physiology, Hamamatsu University School of medicine’, Hamamatsu University School of medicine2 NAGAI NOBUO’ , END0 AKIRA’, TAKAHASHI TAKADA YUMIK02, TAKADA AKIKAZU’
HIROSI’,
Department
of Pasophysiology,
IHARA HAYATO’ , URANO TETSUMEP,
Tissue plasminogen activator (tPA) is a secretory serine protease and converts inactive plasminogen to active plasmin. Plasmin then degrades fibrin (fibrinolysis). tPA has been suggested to participate in -neural plasticity and delayed neuronal cell death in central nervous system, yet it’s functions is not clear. To-study the possible function of tPA, we measured tPA antigen, fibrinolytic activity and extracellular proteolysis in rat hippocampus after.lateral cerebroventricle injection of kainic acid (KA) which caused delayed neuronal cell death of hippocampal neurons. KA injection caused increase in tPA antigen and activity, together with an alteration of positive staining pattern in the hippocampus by anti laminin antiserum within 8 hours. These results suggested that increase in extracellular fibrinolytic activity by tPA contribute to neural cell death by KA injection possibly through the alteration of matrix structure.