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The effects of social defeat experience on anxiety-like behavior and social memory in male hamster
S194
Abstracts
Trait Anxiety Inventory (STAI) and visual analog scale were measured during the cognitive and emotional oddball tasks in healthy volunteers. Our preliminary results suggest that the high state of anxiety appears to affect the performance scores and reaction times not only on the emotional task but also on the cognitive task without emotional loads. doi:10.1016/j.neures.2009.09.1050
P2-o17 An investigation of eavesdropping and consequential changes in golden hamsters Ming-tsung Kuo, Wei-Chun Yu, Cheng-I. Shang, Ching-Hsun Huang, Wen-Sung Lai Department of Psychology, National Taiwan University, Taipei, Taiwan Gathering information from interactions between others is termed eavesdropping which has been studied mainly in certain fishes, birds and humans, but not in other mammals. Using male golden hamsters and their agonistic behavior, we developed a new behavioral model to study eavesdropping. In this study, there are 2 experiments aiming at investigating behavioral changes of male observers after a 3-day observation of two male demonstrators either fighting or interacting neutrally. In Exp 1, fighting naive males spent more time to approach the winning demonstrator in a U-maze immediately or one day after the 3-day observation. In contrast to Exp 1, male observers in Exp 2 received one defeated experience previously from a novel fighter displayed opposite behavioral pattern in the U-maze test after the observation. Taken together, these results suggest that male hamsters eavesdrop too and the defeated experience affects the ways they use the information in subsequent encounter and responses. doi:10.1016/j.neures.2009.09.1051
P2-o18 The effects of social defeat experience on anxiety-like behavior and social memory in male hamster Ching-Hsun Huang, Ming-Tsung Kuo, Wei-Chun Yu, Wen-Sung Lai Dept Psychol, NTU, Taipei, Taiwan In present study, we take advantage of male hamsters and their aggressive behavior to investigate the consequence of social defeat and drug manipulations. In Exp 1, groups of males with different defeated experience were tested in a non-social context and our data indicated that single but not repeated defeat has no effect on generating non-social anxiety. In Exp 2, males with either single or no defeated experience were tested with different intruders in a familiar social context. Defeated males responded differently to different intruders indicating social anxiety/memory were formed after the defeat. In Exp 3, in an unfamiliar social context, males injected with anisomycin right after the defeat had impaired long-term social memory whereas the injection of propranolol has no effect. These results suggest that hamsters received single defeated experience generates fear social memory which requires de novo protein synthesis and increase anxiety-like behavior toward its opponent. doi:10.1016/j.neures.2009.09.1052
P2-o19 Metabotropic glutamate receptor subtype 7 ablation causes deficit in social behaviors Miwako Masugi-Tokita 1 , Peter Josef Flor 2,3 , Herman van der Putten 3 , Mitsuhiro Kawata 1 1 Dept of Anatomy and Neurobiology, Kyoto Prefectural Univ of Med, Kyoto, Japan; 2 Univ of Regensburg, Regensburg, Germany; 3 Novartis Institutes for BioMedical Research, Basel, Switzerland
Metabotropic glutamate receptors (mGluRs) consist of eight different subtypes and exert their effects on second messengers and ion channels via G-proteins. The function of individual mGluR subtypes in the CNS, however, largely remains to be clarified. Since mGluR7 is widely distributed in the brain, it is expected to be involbed in certain types of behaviors. We examined the aggressive behavior in male wild-type and mGluR7 knockout littermates, using a resident-intruder paradigm. Wild-type mice displayed intense aggression against olfactory bulbectomized intruders. In comparison, mGluR7 knockout mice showed significantly reduced levels of aggression. Furthermore mGluR7 knockout mice showed more grooming-like behavior against intruders than wild-type littermates. These results indicate that mGluR7 deficiency in male causes an impairment of social interactions. doi:10.1016/j.neures.2009.09.1053
P2-o20 The effects of juvenile social environment on central neuropeptides and behaviors associated with emotion and social recognition Kenjiro Tanaka, Yoji Osako, Kazunari Yuri Dept Neurobiol Anat, Kochi Med School, Kochi, Japan Stressful social experiences during early-life can increase the risk of developing mental disorders. We hypothesized that a lack of social stimuli should adversely affect developmental arginine vasopressin (AVP) and oxytocin (OXT) systems, whch are closely related to a regulation of emotion and sociality. Rats were weaned at 23 days of age, and divided into group- or isolation-reared conditions. At 38–50 days of age, they were estimated central AVP- and OXT-immunoreactivity (ir) as well as its related behaviors: anxiety, depression, and social recognition. The results from immunohistochemistry showed that male isolates had lower AVP-ir, and that female isolates had lower OXT-ir in parvocellular divisions of the paraventricular hypothalamic nucleus, compared with group-reared counterparts. In the behavioral tests, male and female isolates had anxiogenic profile and difficulty with social recognition, respectively. Juvenile social environment may play a critical role in neuronal and behavioral development. doi:10.1016/j.neures.2009.09.1054
P2-p01 Neonatal maternal separation disrupts the onset and maintenance of aggressive behavior in pubertal male mice Mumeko Tsuda, Yuki Tanahara, Kazuyo Nagata, Sonoko Ogawa Lab of Behavioral Neuroendocrinology, Univ of Tsukuba, Japan We reported that MS possibly delays the onset of male aggression during the pubertal period using estrogen receptor  knockout mice. In this study, we further investigated the MS effect on the development of aggression in pubertal C57BL/6J males. Non-MS control and MS males were tested for aggression between 5 wk to 9 wk of age. Consistent with our previous studies, non-MS control males exhibited higher levels of aggression at 6 wks of age compared to 5 wks, and continued to be aggressive for the following weeks, suggesting their pubertal onset of aggression. In contrast, MS males displayed greatly reduced levels of aggression throughout all weeks of testing. Taken together, these results suggest that MS is not delaying, but inhibits the pubertal onset of aggression. This could be the result of MS disrupting the development of neural systems regulating the onset and maintenance of male aggressive behaviors. Currently, we are investigating MS effects on the development of the HPG axis, 5-HT, and AVP systems. doi:10.1016/j.neures.2009.09.1055
P2-p02 Twelve-hour pair housing attenuates stress-induced hyperthermia in response to conditioned stimulus Yuka Kodama, Yasushi Kiyokawa, Yukari Takeuchi, Yuji Mori Lab of Vet Ethol, Univ of Tokyo, Tokyo, Japan We previously reported in male Wistar rats that pair housing with a conspecific animal after fear conditioning attenuated stress-induced hyperthermia in response to an auditory conditioned stimulus that had been paired with foot shocks. In this study, we first investigated whether pair housing could attenuate autonomic response by inhibiting memory consolidation. Pair housing started 24 h after fear conditioning, when memory had already been consolidated, decreased autonomic response. We then examined how many hours were required for pair housing. By pair housing for 6, 12, 18, or 24 h, it was revealed that at least 12 h of pair housing was necessary to diminish autonomic response. These results suggest that more than 12-h pair housing attenuates autonomic response by some mechanism other than inhibiting memory consolidation. doi:10.1016/j.neures.2009.09.1056
P2-p03 Main olfactory system is essential for the social buffering of conditioned fear responses in male rats Yasushi Kiyokawa 1,2,3 , Yukari Takeuchi 1 , Masugi Nishihara 2 , Yuji Mori 1 1
Lab Vet Etho, Univ of Tokyo, Tokyo, Japan; 2 Lab Vet Physiol, Univ of Tokyo, Tokyo; 3 JSPS Research Fellow, Tokyo, Japan
We previously reported in adult Wistar male rats that the presence of an associate rat mitigated conditioned fear responses to an auditory conditioned stimulus (CS) without physical contact. In this study, we investigated the role of the main olfactory system in this social buffering. The main olfactory epithelium of the subject was lesioned by intranasal injection of ZnSO4 two days before the conditioning day. Then, they were fear-conditioned to an auditory CS and, twenty-four hours later,
Abstracts
Trait Anxiety Inventory (STAI) and visual analog scale were measured during the cognitive and emotional oddball tasks in healthy volunteers. Our preliminary results suggest that the high state of anxiety appears to affect the performance scores and reaction times not only on the emotional task but also on the cognitive task without emotional loads. doi:10.1016/j.neures.2009.09.1050
P2-o17 An investigation of eavesdropping and consequential changes in golden hamsters Ming-tsung Kuo, Wei-Chun Yu, Cheng-I. Shang, Ching-Hsun Huang, Wen-Sung Lai Department of Psychology, National Taiwan University, Taipei, Taiwan Gathering information from interactions between others is termed eavesdropping which has been studied mainly in certain fishes, birds and humans, but not in other mammals. Using male golden hamsters and their agonistic behavior, we developed a new behavioral model to study eavesdropping. In this study, there are 2 experiments aiming at investigating behavioral changes of male observers after a 3-day observation of two male demonstrators either fighting or interacting neutrally. In Exp 1, fighting naive males spent more time to approach the winning demonstrator in a U-maze immediately or one day after the 3-day observation. In contrast to Exp 1, male observers in Exp 2 received one defeated experience previously from a novel fighter displayed opposite behavioral pattern in the U-maze test after the observation. Taken together, these results suggest that male hamsters eavesdrop too and the defeated experience affects the ways they use the information in subsequent encounter and responses. doi:10.1016/j.neures.2009.09.1051
P2-o18 The effects of social defeat experience on anxiety-like behavior and social memory in male hamster Ching-Hsun Huang, Ming-Tsung Kuo, Wei-Chun Yu, Wen-Sung Lai Dept Psychol, NTU, Taipei, Taiwan In present study, we take advantage of male hamsters and their aggressive behavior to investigate the consequence of social defeat and drug manipulations. In Exp 1, groups of males with different defeated experience were tested in a non-social context and our data indicated that single but not repeated defeat has no effect on generating non-social anxiety. In Exp 2, males with either single or no defeated experience were tested with different intruders in a familiar social context. Defeated males responded differently to different intruders indicating social anxiety/memory were formed after the defeat. In Exp 3, in an unfamiliar social context, males injected with anisomycin right after the defeat had impaired long-term social memory whereas the injection of propranolol has no effect. These results suggest that hamsters received single defeated experience generates fear social memory which requires de novo protein synthesis and increase anxiety-like behavior toward its opponent. doi:10.1016/j.neures.2009.09.1052
P2-o19 Metabotropic glutamate receptor subtype 7 ablation causes deficit in social behaviors Miwako Masugi-Tokita 1 , Peter Josef Flor 2,3 , Herman van der Putten 3 , Mitsuhiro Kawata 1 1 Dept of Anatomy and Neurobiology, Kyoto Prefectural Univ of Med, Kyoto, Japan; 2 Univ of Regensburg, Regensburg, Germany; 3 Novartis Institutes for BioMedical Research, Basel, Switzerland
Metabotropic glutamate receptors (mGluRs) consist of eight different subtypes and exert their effects on second messengers and ion channels via G-proteins. The function of individual mGluR subtypes in the CNS, however, largely remains to be clarified. Since mGluR7 is widely distributed in the brain, it is expected to be involbed in certain types of behaviors. We examined the aggressive behavior in male wild-type and mGluR7 knockout littermates, using a resident-intruder paradigm. Wild-type mice displayed intense aggression against olfactory bulbectomized intruders. In comparison, mGluR7 knockout mice showed significantly reduced levels of aggression. Furthermore mGluR7 knockout mice showed more grooming-like behavior against intruders than wild-type littermates. These results indicate that mGluR7 deficiency in male causes an impairment of social interactions. doi:10.1016/j.neures.2009.09.1053
P2-o20 The effects of juvenile social environment on central neuropeptides and behaviors associated with emotion and social recognition Kenjiro Tanaka, Yoji Osako, Kazunari Yuri Dept Neurobiol Anat, Kochi Med School, Kochi, Japan Stressful social experiences during early-life can increase the risk of developing mental disorders. We hypothesized that a lack of social stimuli should adversely affect developmental arginine vasopressin (AVP) and oxytocin (OXT) systems, whch are closely related to a regulation of emotion and sociality. Rats were weaned at 23 days of age, and divided into group- or isolation-reared conditions. At 38–50 days of age, they were estimated central AVP- and OXT-immunoreactivity (ir) as well as its related behaviors: anxiety, depression, and social recognition. The results from immunohistochemistry showed that male isolates had lower AVP-ir, and that female isolates had lower OXT-ir in parvocellular divisions of the paraventricular hypothalamic nucleus, compared with group-reared counterparts. In the behavioral tests, male and female isolates had anxiogenic profile and difficulty with social recognition, respectively. Juvenile social environment may play a critical role in neuronal and behavioral development. doi:10.1016/j.neures.2009.09.1054
P2-p01 Neonatal maternal separation disrupts the onset and maintenance of aggressive behavior in pubertal male mice Mumeko Tsuda, Yuki Tanahara, Kazuyo Nagata, Sonoko Ogawa Lab of Behavioral Neuroendocrinology, Univ of Tsukuba, Japan We reported that MS possibly delays the onset of male aggression during the pubertal period using estrogen receptor  knockout mice. In this study, we further investigated the MS effect on the development of aggression in pubertal C57BL/6J males. Non-MS control and MS males were tested for aggression between 5 wk to 9 wk of age. Consistent with our previous studies, non-MS control males exhibited higher levels of aggression at 6 wks of age compared to 5 wks, and continued to be aggressive for the following weeks, suggesting their pubertal onset of aggression. In contrast, MS males displayed greatly reduced levels of aggression throughout all weeks of testing. Taken together, these results suggest that MS is not delaying, but inhibits the pubertal onset of aggression. This could be the result of MS disrupting the development of neural systems regulating the onset and maintenance of male aggressive behaviors. Currently, we are investigating MS effects on the development of the HPG axis, 5-HT, and AVP systems. doi:10.1016/j.neures.2009.09.1055
P2-p02 Twelve-hour pair housing attenuates stress-induced hyperthermia in response to conditioned stimulus Yuka Kodama, Yasushi Kiyokawa, Yukari Takeuchi, Yuji Mori Lab of Vet Ethol, Univ of Tokyo, Tokyo, Japan We previously reported in male Wistar rats that pair housing with a conspecific animal after fear conditioning attenuated stress-induced hyperthermia in response to an auditory conditioned stimulus that had been paired with foot shocks. In this study, we first investigated whether pair housing could attenuate autonomic response by inhibiting memory consolidation. Pair housing started 24 h after fear conditioning, when memory had already been consolidated, decreased autonomic response. We then examined how many hours were required for pair housing. By pair housing for 6, 12, 18, or 24 h, it was revealed that at least 12 h of pair housing was necessary to diminish autonomic response. These results suggest that more than 12-h pair housing attenuates autonomic response by some mechanism other than inhibiting memory consolidation. doi:10.1016/j.neures.2009.09.1056
P2-p03 Main olfactory system is essential for the social buffering of conditioned fear responses in male rats Yasushi Kiyokawa 1,2,3 , Yukari Takeuchi 1 , Masugi Nishihara 2 , Yuji Mori 1 1
Lab Vet Etho, Univ of Tokyo, Tokyo, Japan; 2 Lab Vet Physiol, Univ of Tokyo, Tokyo; 3 JSPS Research Fellow, Tokyo, Japan
We previously reported in adult Wistar male rats that the presence of an associate rat mitigated conditioned fear responses to an auditory conditioned stimulus (CS) without physical contact. In this study, we investigated the role of the main olfactory system in this social buffering. The main olfactory epithelium of the subject was lesioned by intranasal injection of ZnSO4 two days before the conditioning day. Then, they were fear-conditioned to an auditory CS and, twenty-four hours later,