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Progression of epilepsy and anxiety via brain growth hormone signaling
e432
Abstracts / Neuroscience Research 68S (2010) e335–e446
anxiety-related behavior. Thus, the level of activin in the brain deeply correlates with general locomotor activity and anxiety. We proposed these transgenic mice as new animal models for the bipolar disorder. However, there is no information about downstream targets, which influence anxietyrelated behavior. To know this information, we analyzed these transgenic mice using 2-dimensional gel electrophoresis and mass spectrometry. We found numerous protein expression and posttranslational changes in the hippocampus. Our findings may be useful for the screening compounds in the development of new mechanistically novel anti-depressant drugs.
progression, respectively. In addition it has been reported that animal models of temporal lobe epilepsy exhibit emotional changes, while, the present administrations of the hormone or an antagonist of the hormone receptor into the hippocampus without kindling-stimulations resulted in increases of self-grooming and defecation that reflect anxiogenic effects or elicited hypolocomotion and realing, respectively. Finally, we demonstrated that growth hormone signaling is a key system to induce epileptogenesis and anxiety. doi:10.1016/j.neures.2010.07.1915
doi:10.1016/j.neures.2010.07.1913
P3-q02 The Rap1 guanine nucleotide exchange factor RAGEF-1 is essential for the proper development of the mouse cerebral cortex
Shymaa E. Bilasy 1 , Takaya Satoh 1 , Toshio Terashima 2 , Tohru Kataoka 1
1 Division of Molecular Biology, Department of Biochemistry and Molecular Biology, Graduate school of Medicine - Kobe University, Kobe, Japan 2 Division of Developmental Neurobiology, Department of Physiology and Cell Biology, Graduate school of Medicine, Kobe University, Kobe, Japan
P3-q04 Effects of reward and punishment on exploratory behavior in rats Jan Lauwereyns 1 , Muneyoshi Takahashi 2 , Minoru Tsukada 2 1
Graduate School of Systems Life Sciences, Kyushu University 2 Brain Science Institute, Tamagawa University Previous research has provided abundant evidence that negative as well as positive reinforcers can elicit operant responding in rats. Less is known, however, about the relative impact of positive versus negative reinforcers on the dynamics of exploration in a complex setting, including old and new stimuli. To study such dynamics, we devised a new behavioral paradigm consisting of an initial learning phase, followed by a test of exploration. In the initial learning phase, rats acquired an operant nose-poke response to a visual (LED) onset at the central hole in the front wall of a Skinner box. We trained two groups of rats, with different types of reinforcement: Group 1 (appetitive learning) obtained food pellets as reinforcement for correct responding, whereas Group 2 (appetitive and avoidance learning) obtained food pellets and avoided foot shocks as reinforcement for correct responding. Once both groups had established similar, near-perfect levels of performance, we introduced a first exploration test, in which a second visual (LED) onset was presented simultaneously with the visual onset at the center. The rats were free to continue responding to the central hole (with the same reinforcement schedule for central responding as during the initial learning). However, the rats obtained a larger amount of food pellets for responding to the peripheral hole (Group 1 and Group 2) as well as avoiding a foot shock (Group 2). Overall, as compared to rats in Group 1, the rats that underwent both appetitive and avoidance learning showed more efficient exploration, switching to peripheral responding. These data cannot easily be accommodated by operant conditioning models, according to which the rats in Group 2 should have been particularly motivated to continue responding at the central hole. Instead, we propose that their exploratory behavior was aimed at disambiguating the complex setting.
RA-GEF-1 is a guanine nucleotide exchange factor for Rap1, which associates with Rap1-GTP and M-Ras-GTP. We have been investigating its in vivo role in formation of the adult cerebral cortex using dorsal telencephalon-specific RAGEF-1 conditional knockout (cKO) mice. RA-GEF-1 cKO mice showed severe defects in their brain structures including the occurrence of an ectopic cortical mass (ECM) underlying a relatively normal cortex, the enlargement of the lateral ventricles and the agenesis of the corpus callosum and the anterior commissure. The ECM was occupied by cortical neurons from layer II to layer VI arranged randomly. Interestingly, we observed a higher tendency for the presence of layers II/III (late born) neurons in the ECM rather than layers V/VI (early born) neurons as verified by immunostaining for CUX1 and TBR1. Further, immunostaining for the layer I marker Reelin indicated the absence of Cajal–Retzius cells from the ECM, indicating that preplate splitting occurred normally in cKO mice. Therefore, we conclude that RA-GEF-1 deficiency severely affected the migration of late born neurons after preplate splitting (embryonic day 13). Studying the cortical myeloarchitecture with immunostaining for myelin basic protein revealed the agenesis of the corpus callosum and the anterior commissure fibers. Retrograde tracing verified the impairment in the bilateral integration of information via the corpus callosum and the anterior commissure. Anterograde tracing verified the inability of callosal axons to cross the midline, thereby forming Probst bundles on the ipsilateral side. Anterograde tracing of the anterior limb of the anterior commissure with DiI confirmed an aberrant guidance and deviation of the fibers from their original tract. We are currently performing detailed analysis to uncover the cellular events involved in the development of RA-GEF-1 phenotypes.
P3-q05 Histological analyses of the role of the Rorb in the mouse retina
doi:10.1016/j.neures.2010.07.1914
Atsushi Yoshiki , Ayumi Murakami, Kazuyuki Mekada, Hatsumi Nakata, Satoshi Oota
doi:10.1016/j.neures.2010.07.1916
RIKEN BioResource Center, Tsukuba, Japan
P3-q03 Progression of epilepsy and anxiety via brain growth hormone signaling Keiko Kato 1,2 , Hiroki Kanno 2 , Yoshio Hirabayashi 3 1
Faculty of Life Science, Kyoto Sangyo University 2 Graduate School of Life and Environmental Sciences, Osaka Prefecture University 3 RIKEN, Brain Science Institute About one-half of patients with refractory epilepsy are characterized as having mesial temporal lobe epilepsy with foci in the amygdaloid complex, hippocampus, and surrounding cortex. To screen candidate molecules that be involved in refractory epilepsy, we used amygdala-kindled mice, a model of temporal lobe epilepsy. Using real-time RT-PCR and Western blot analyses, we demonstrated that the expression of growth hormone was up-regulated along neural circuits during and following development of epilepsy. The up-regulation was associated with increased phosphorylation/activation of Stat5 and expressions of the Serum Response Element (SRE)-regulated genes, Fos, Egr1, and Junb. On the other hand, administrations of the hormone and an antagonist of the hormone receptor into the hippocampus without kindlingstimulation up-regulated and inhibited the expression of Egr1, respectively. These results suggested that kindling-stimulation enhanced expression of the hormone, leading to that growth hormone signaling activated the signal transduction pathway containing transcription of Egr1 in brain. Furthermore, administrations of the hormone and an inhibitor of its secretion into the hippocampus enhanced the progression of kindling and elicited a delay in the
We have recovered independently two similar behavioral mutant mice with retinal degeneration and affected gait. Genome analyses revealed one mutation, designated hugger1 (hug1) was a point mutation in the exon 4 of isoforms 1 and 2, causing G to A base substitution and G to E amino acid exchange. Another mutation (hugger2, hug2) was a deletion of the exon 1 of isoform 1 which specifically used only for the isofrom 1. To elucidate the role of Rorb in the development of retina, we conducted histological analyses of retinal tissues of different genotypes of the two Rorb mutations, hug1/hug1, hug1/+, hug2/hug2, hug2/+, hug1/hug2 and wild-type. As results, the severity of the retinal degeneration significantly differed among genotyes as follows from the severer phenotype to normal: hug1/hug1 > hug1/hug2 > hug2/hug2 > hug/+, hug2/+, +/+. The results indicated that the hug1 and hug2 mutations in the Rorb caused degenerative retinal phnotypes of different severity, suggesting the distinct roles of Rorb isoforms in the development of the mouse neural retina. doi:10.1016/j.neures.2010.07.1917
Abstracts / Neuroscience Research 68S (2010) e335–e446
anxiety-related behavior. Thus, the level of activin in the brain deeply correlates with general locomotor activity and anxiety. We proposed these transgenic mice as new animal models for the bipolar disorder. However, there is no information about downstream targets, which influence anxietyrelated behavior. To know this information, we analyzed these transgenic mice using 2-dimensional gel electrophoresis and mass spectrometry. We found numerous protein expression and posttranslational changes in the hippocampus. Our findings may be useful for the screening compounds in the development of new mechanistically novel anti-depressant drugs.
progression, respectively. In addition it has been reported that animal models of temporal lobe epilepsy exhibit emotional changes, while, the present administrations of the hormone or an antagonist of the hormone receptor into the hippocampus without kindling-stimulations resulted in increases of self-grooming and defecation that reflect anxiogenic effects or elicited hypolocomotion and realing, respectively. Finally, we demonstrated that growth hormone signaling is a key system to induce epileptogenesis and anxiety. doi:10.1016/j.neures.2010.07.1915
doi:10.1016/j.neures.2010.07.1913
P3-q02 The Rap1 guanine nucleotide exchange factor RAGEF-1 is essential for the proper development of the mouse cerebral cortex
Shymaa E. Bilasy 1 , Takaya Satoh 1 , Toshio Terashima 2 , Tohru Kataoka 1
1 Division of Molecular Biology, Department of Biochemistry and Molecular Biology, Graduate school of Medicine - Kobe University, Kobe, Japan 2 Division of Developmental Neurobiology, Department of Physiology and Cell Biology, Graduate school of Medicine, Kobe University, Kobe, Japan
P3-q04 Effects of reward and punishment on exploratory behavior in rats Jan Lauwereyns 1 , Muneyoshi Takahashi 2 , Minoru Tsukada 2 1
Graduate School of Systems Life Sciences, Kyushu University 2 Brain Science Institute, Tamagawa University Previous research has provided abundant evidence that negative as well as positive reinforcers can elicit operant responding in rats. Less is known, however, about the relative impact of positive versus negative reinforcers on the dynamics of exploration in a complex setting, including old and new stimuli. To study such dynamics, we devised a new behavioral paradigm consisting of an initial learning phase, followed by a test of exploration. In the initial learning phase, rats acquired an operant nose-poke response to a visual (LED) onset at the central hole in the front wall of a Skinner box. We trained two groups of rats, with different types of reinforcement: Group 1 (appetitive learning) obtained food pellets as reinforcement for correct responding, whereas Group 2 (appetitive and avoidance learning) obtained food pellets and avoided foot shocks as reinforcement for correct responding. Once both groups had established similar, near-perfect levels of performance, we introduced a first exploration test, in which a second visual (LED) onset was presented simultaneously with the visual onset at the center. The rats were free to continue responding to the central hole (with the same reinforcement schedule for central responding as during the initial learning). However, the rats obtained a larger amount of food pellets for responding to the peripheral hole (Group 1 and Group 2) as well as avoiding a foot shock (Group 2). Overall, as compared to rats in Group 1, the rats that underwent both appetitive and avoidance learning showed more efficient exploration, switching to peripheral responding. These data cannot easily be accommodated by operant conditioning models, according to which the rats in Group 2 should have been particularly motivated to continue responding at the central hole. Instead, we propose that their exploratory behavior was aimed at disambiguating the complex setting.
RA-GEF-1 is a guanine nucleotide exchange factor for Rap1, which associates with Rap1-GTP and M-Ras-GTP. We have been investigating its in vivo role in formation of the adult cerebral cortex using dorsal telencephalon-specific RAGEF-1 conditional knockout (cKO) mice. RA-GEF-1 cKO mice showed severe defects in their brain structures including the occurrence of an ectopic cortical mass (ECM) underlying a relatively normal cortex, the enlargement of the lateral ventricles and the agenesis of the corpus callosum and the anterior commissure. The ECM was occupied by cortical neurons from layer II to layer VI arranged randomly. Interestingly, we observed a higher tendency for the presence of layers II/III (late born) neurons in the ECM rather than layers V/VI (early born) neurons as verified by immunostaining for CUX1 and TBR1. Further, immunostaining for the layer I marker Reelin indicated the absence of Cajal–Retzius cells from the ECM, indicating that preplate splitting occurred normally in cKO mice. Therefore, we conclude that RA-GEF-1 deficiency severely affected the migration of late born neurons after preplate splitting (embryonic day 13). Studying the cortical myeloarchitecture with immunostaining for myelin basic protein revealed the agenesis of the corpus callosum and the anterior commissure fibers. Retrograde tracing verified the impairment in the bilateral integration of information via the corpus callosum and the anterior commissure. Anterograde tracing verified the inability of callosal axons to cross the midline, thereby forming Probst bundles on the ipsilateral side. Anterograde tracing of the anterior limb of the anterior commissure with DiI confirmed an aberrant guidance and deviation of the fibers from their original tract. We are currently performing detailed analysis to uncover the cellular events involved in the development of RA-GEF-1 phenotypes.
P3-q05 Histological analyses of the role of the Rorb in the mouse retina
doi:10.1016/j.neures.2010.07.1914
Atsushi Yoshiki , Ayumi Murakami, Kazuyuki Mekada, Hatsumi Nakata, Satoshi Oota
doi:10.1016/j.neures.2010.07.1916
RIKEN BioResource Center, Tsukuba, Japan
P3-q03 Progression of epilepsy and anxiety via brain growth hormone signaling Keiko Kato 1,2 , Hiroki Kanno 2 , Yoshio Hirabayashi 3 1
Faculty of Life Science, Kyoto Sangyo University 2 Graduate School of Life and Environmental Sciences, Osaka Prefecture University 3 RIKEN, Brain Science Institute About one-half of patients with refractory epilepsy are characterized as having mesial temporal lobe epilepsy with foci in the amygdaloid complex, hippocampus, and surrounding cortex. To screen candidate molecules that be involved in refractory epilepsy, we used amygdala-kindled mice, a model of temporal lobe epilepsy. Using real-time RT-PCR and Western blot analyses, we demonstrated that the expression of growth hormone was up-regulated along neural circuits during and following development of epilepsy. The up-regulation was associated with increased phosphorylation/activation of Stat5 and expressions of the Serum Response Element (SRE)-regulated genes, Fos, Egr1, and Junb. On the other hand, administrations of the hormone and an antagonist of the hormone receptor into the hippocampus without kindlingstimulation up-regulated and inhibited the expression of Egr1, respectively. These results suggested that kindling-stimulation enhanced expression of the hormone, leading to that growth hormone signaling activated the signal transduction pathway containing transcription of Egr1 in brain. Furthermore, administrations of the hormone and an inhibitor of its secretion into the hippocampus enhanced the progression of kindling and elicited a delay in the
We have recovered independently two similar behavioral mutant mice with retinal degeneration and affected gait. Genome analyses revealed one mutation, designated hugger1 (hug1) was a point mutation in the exon 4 of isoforms 1 and 2, causing G to A base substitution and G to E amino acid exchange. Another mutation (hugger2, hug2) was a deletion of the exon 1 of isoform 1 which specifically used only for the isofrom 1. To elucidate the role of Rorb in the development of retina, we conducted histological analyses of retinal tissues of different genotypes of the two Rorb mutations, hug1/hug1, hug1/+, hug2/hug2, hug2/+, hug1/hug2 and wild-type. As results, the severity of the retinal degeneration significantly differed among genotyes as follows from the severer phenotype to normal: hug1/hug1 > hug1/hug2 > hug2/hug2 > hug/+, hug2/+, +/+. The results indicated that the hug1 and hug2 mutations in the Rorb caused degenerative retinal phnotypes of different severity, suggesting the distinct roles of Rorb isoforms in the development of the mouse neural retina. doi:10.1016/j.neures.2010.07.1917