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Hiroshi Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Social Isolation Stress-induced oxidative damage in mouse brain and its modulation by majonoside-R2, a Vietnamese ginseng saponin.
Biological & pharmaceutical bulletin, 2005Co-Authors: Nguyen Thi Thu Huong, Hiroshi Watanabe, Yukihisa Murakami, Michihisa Tohda, Kinzo MatsumotoAbstract:Stressors with a physical factor such as immobilization, electric foot shock, cold swim, etc., have been shown to produce oxidative damage to membrane lipids in the brain. In this study, we investigated the effect of protracted social Isolation Stress on lipid peroxidation activity in the mouse brain and elucidated the protective effect of majonoside-R2, a major saponin component of Vietnamese ginseng, in mice exposed to social Isolation Stress. Thiobarbituric acid reactive substance levels, one of the end products of lipid peroxidation reaction, were increased in the brains of mice subjected to 6—8 weeks of social Isolation Stress. Measurements of nitric oxide (NO) metabolites (NOx−) also revealed a significant increase of NO production in the brains of socially isolated mice. Moreover, the depletion of brain glutathione content, an endogenous antioxidant, in socially isolated animals occurred in association with the rise in lipid peroxidation. The intraperitoneal administration of majonoside-R2 (10—50 mg/kg) had no effect on thiobarbituric acid reactive substances (TBARS), NO, or glutathione levels in the brains of group-housed control mice but it significantly suppressed the increase in TBARS and NO levels and the decrease in glutathione levels caused by social Isolation Stress. These results suggest that mice subjected to 6—8 weeks of social Isolation Stress produces oxidative damage in the brain partly via enhancement of NO production, and that majonoside-R2 exerts a protective effect by modulating NO and glutathione systems in the brain.
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Social Isolation Stress enhanced liver metastasis of murine colon 26-L5 carcinoma cells by suppressing immune responses in mice
Life sciences, 2000Co-Authors: Takeshi Yamaura, Kinzo Matsumoto, Hiroshi Watanabe, Jun Murata, Koji Murakami, Ikuo SaikiAbstract:We investigated the effect of social Isolation Stress on the formation of experimental liver metastasis resulted from intraportal vein (i.p.v.) injection of colon 26-L5 carcinoma cells in male Balb/c mice, and elucidated some of the underlying mechanism involving the effects of this Stress on cellular immunity. Increases in the colony number and tumor burden were observed in the mice socially isolated before and/or after tumor cell challenge, as compared with the group-housed mice. In addition, exposure of mice to 2 weeks of preIsolation resulted in decreases in the thymus weight and number of thymocytes by 35.8% and 40.2%, respectively, in comparison with the controls. Reduced proliferative response of splenocytes to various stimuli and suppressed splenic NK activity, as well as decreased macrophage-mediated cytotoxicity, were also found in the mice exposed to social Isolation. Thus, these results suggest that social Isolation Stress enhances tumor metastasis in part via its suppressive effect on the immune system of the host.
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involvement of diazepam binding inhibitor and its fragment octadecaneuropeptide in social Isolation Stress induced decrease in pentobarbital sleep in mice
Life Sciences, 1999Co-Authors: Erbo Dong, Kinzo Matsumoto, Michihisa Tohda, Hiroshi WatanabeAbstract:Abstract Diazepam binding inhibitor (DBI) and its fragment, octadecaneuropeptide (ODN), are putative endogenous ligands for benzodiazepine (BZD) receptors and have been shown to act as an inverse BZD receptor agonist in the brain. A previous study suggested that the social Isolation Stress-induced decrease in pentobarbital sleep in mice was partly due to endogenous substances with an inverse BZD receptor agonist-like property. In this study, we examined the effects of DBI and ODN on pentobarbital sleep in group-housed and socially isolated mice to test the possible involvement of DBI and ODN in a social Isolation-induced decrease in pentobarbital sleep. The socially isolated mice showed significantly shorter durations of pentobarbital (50 mg/kg, intraperitoneally, i.p.) sleep compared to the group-housed animals. When injected intracerebroventricularly (i.c.v.), DBI and ODN (3 and 10 nmol) dose-dependently shortened the pentobarbital-induced sleeping time in group-housed mice at the same dose range, but these peptides had no effect on the sleeping time in socially isolated animals. In contrast, flumazenil (16.5–33 nmol, i.c.v.), a BZD receptor antagonist, reversed the pentobarbital sleeping time in socially isolated mice to the level of group-housed animals without affecting the sleeping time in group-housed animals. The effects of DBI and ODN in group-housed mice were significantly blocked by flumazenil (33 nmol, i.c.v.). Moreover, the effect of flumazenil in socially isolated mice was significantly attenuated by DBI and ODN (10 nmol, i.c.v.). These results suggest that the changes in the activity of DBI and/or ODN are partly involved in the social Isolation-induced decrease in the hypnotic action of pentobarbital in mice.
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Involvement of peripheral type of benzodiazepine receptor in social Isolation Stress-induced decrease in pentobarbital sleep in mice.
Life sciences, 1999Co-Authors: Erbo Dong, Kinzo Matsumoto, Hiroshi WatanabeAbstract:Our previous studies have shown that central-type benzodiazepine (BZD) receptors (CBR) and neurosteroids capable of modulating GABA(A) receptor function are involved in the decrease of pentobarbital (PB)-induced sleep caused by social Isolation Stress in mice. In this study, to further clarify the mechanism underlying this decrease, we investigated the possible involvement of peripheral-type BZD receptors (PBR) which play an important role in neurosteroidogenesis in PB sleep in socially isolated mice. Socially isolated mice showed significantly shorter duration of PB-induced sleep than group-housed animals. When injected intracerebroventricularly (i.c.v.), FGIN-1-27 (FGIN, 25-100 nmol), a selective PBR agonist, and PK11195 (PK, 14-28 nmol), a PBR antagonist, and pregnenolone (PREG, 15-30 nmol), a neurosteroid precursor, dose-dependently normalized the PB sleep in isolated mice without having an effect on the group-housed animals. In contrast, pregnenolone sulfate (PS, 24 nmol), an endogenous neurosteroidal negative allosteric modulator of the GABA(A) receptor, reduced PB sleep in group-housed but not isolated mice. PS, at the same dose, significantly attenuated the effects of FGIN (100 nmol), PK (28 nmol) and PREG (30 nmol) in isolated mice, while FGIN (100 nmol), PK (28 nmol) and pregnenolone (30 nmol) significantly blocked the effect of PS (24 nmol) in group-housed mice. These results suggest that the PBR-mediated decrease in the genesis of neurosteroid(s) possessing a GABA(A) receptor agonistic profile is also partly involved in the down regulation of the GABA(A) receptor following long-term social Isolation and contributes to the decrease of PB-induced sleep in Isolation Stressed mice.
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Central corticotropin-releasing factor and benzodiazepine receptor systems are involved in the social Isolation Stress-induced decrease in ethanol sleep in mice
Brain research, 1997Co-Authors: Kinzo Matsumoto, Kazuma Ojima, Hiroshi WatanabeAbstract:Social Isolation Stress has been demonstrated to decrease the hypnotic activity of ethanol in rodents. In this study, the role of central corticotropin-releasing factor (CRF) and GABA(A)/benzodiazepine (BZD) receptor systems in the social Isolation Stress-induced decrease in the hypnotic activity of ethanol in mice was investigated by examining the effect of alpha-helical CRF(9-41) (alpha hCRF) and flumazenil, antagonists of CRF and BZD receptors, respectively, on ethanol-induced sleep in group-housed and socially isolated mice. We also tested whether social Isolation Stress affects the ability of ethanol to enhance the GABA-induced 36Cl- influx into a synaptoneurosomal preparation of mouse forebrain. Social Isolation Stress significantly decreased both the ethanol (4 g/kg i.p.)-induced and pentobarbital (50 mg/kg i.p.)-induced sleeping times, while this Stress had no effect on chloral hydrate (325 mg/kg i.p.)-induced sleep. The i.c.v. injection of alpha hCRF (6.5 nmol) and flumazenil (33 nmol) antagonized the social Isolation Stress-induced decrease in the ethanol sleep without affecting ethanol sleep in group-housed animals. Social Isolation Stress significantly attenuated the ability of GABA to stimulate 36Cl- influx but this Stress had no effect on the ability of ethanol to enhance GABA-induced 36Cl- influx. These results suggest that the functional changes in central CRF and GABA(A)/BZD receptor systems are involved in the social Isolation Stress-induced decrease in the hypnotic activity of ethanol in mice.
Kinzo Matsumoto - One of the best experts on this subject based on the ideXlab platform.
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Social Isolation Stress down-regulates cortical early growth response 1 (Egr-1) expression in mice.
Neuroscience research, 2012Co-Authors: Kinzo Matsumoto, Kazuya Ono, Hirofumi Ouchi, Ryohei Tsushima, Yukihisa MurakamiAbstract:Social Isolation Stress induces behavioral disturbances such as aggression, cognitive impairments, and deficits in prepulse inhibition in mice. Social Isolation mice have, therefore, been studied as an animal model of neuropsychiatric disorders such as schizophrenia. Recently, the decrease in early growth response (Egr) gene expression levels were reported in the post-mortem brains of schizophrenia patients. In this study, we investigate the effects of social Isolation Stress on the expression levels of Egr mRNA and protein in the frontal cortex. Social Isolation Stress exposure significantly down-regulated the expression of Egr-1 protein and Egr-1 gene transcript in nucleus of cortical neurons in a manner dependent on a social Isolation period. This Stress had no effect on the expression level of Egr-1 in the striatum or the expression levels of other Egr family members (Egr-2, -3, and -4) in the frontal cortex. These results suggest that the decrease in Egr-1 expression in the frontal cortex may be involved in social Isolation Stress-induced behavioral abnormalities.
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Social Isolation Stress-induced oxidative damage in mouse brain and its modulation by majonoside-R2, a Vietnamese ginseng saponin.
Biological & pharmaceutical bulletin, 2005Co-Authors: Nguyen Thi Thu Huong, Hiroshi Watanabe, Yukihisa Murakami, Michihisa Tohda, Kinzo MatsumotoAbstract:Stressors with a physical factor such as immobilization, electric foot shock, cold swim, etc., have been shown to produce oxidative damage to membrane lipids in the brain. In this study, we investigated the effect of protracted social Isolation Stress on lipid peroxidation activity in the mouse brain and elucidated the protective effect of majonoside-R2, a major saponin component of Vietnamese ginseng, in mice exposed to social Isolation Stress. Thiobarbituric acid reactive substance levels, one of the end products of lipid peroxidation reaction, were increased in the brains of mice subjected to 6—8 weeks of social Isolation Stress. Measurements of nitric oxide (NO) metabolites (NOx−) also revealed a significant increase of NO production in the brains of socially isolated mice. Moreover, the depletion of brain glutathione content, an endogenous antioxidant, in socially isolated animals occurred in association with the rise in lipid peroxidation. The intraperitoneal administration of majonoside-R2 (10—50 mg/kg) had no effect on thiobarbituric acid reactive substances (TBARS), NO, or glutathione levels in the brains of group-housed control mice but it significantly suppressed the increase in TBARS and NO levels and the decrease in glutathione levels caused by social Isolation Stress. These results suggest that mice subjected to 6—8 weeks of social Isolation Stress produces oxidative damage in the brain partly via enhancement of NO production, and that majonoside-R2 exerts a protective effect by modulating NO and glutathione systems in the brain.
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Social Isolation Stress enhanced liver metastasis of murine colon 26-L5 carcinoma cells by suppressing immune responses in mice
Life sciences, 2000Co-Authors: Takeshi Yamaura, Kinzo Matsumoto, Hiroshi Watanabe, Jun Murata, Koji Murakami, Ikuo SaikiAbstract:We investigated the effect of social Isolation Stress on the formation of experimental liver metastasis resulted from intraportal vein (i.p.v.) injection of colon 26-L5 carcinoma cells in male Balb/c mice, and elucidated some of the underlying mechanism involving the effects of this Stress on cellular immunity. Increases in the colony number and tumor burden were observed in the mice socially isolated before and/or after tumor cell challenge, as compared with the group-housed mice. In addition, exposure of mice to 2 weeks of preIsolation resulted in decreases in the thymus weight and number of thymocytes by 35.8% and 40.2%, respectively, in comparison with the controls. Reduced proliferative response of splenocytes to various stimuli and suppressed splenic NK activity, as well as decreased macrophage-mediated cytotoxicity, were also found in the mice exposed to social Isolation. Thus, these results suggest that social Isolation Stress enhances tumor metastasis in part via its suppressive effect on the immune system of the host.
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involvement of diazepam binding inhibitor and its fragment octadecaneuropeptide in social Isolation Stress induced decrease in pentobarbital sleep in mice
Life Sciences, 1999Co-Authors: Erbo Dong, Kinzo Matsumoto, Michihisa Tohda, Hiroshi WatanabeAbstract:Abstract Diazepam binding inhibitor (DBI) and its fragment, octadecaneuropeptide (ODN), are putative endogenous ligands for benzodiazepine (BZD) receptors and have been shown to act as an inverse BZD receptor agonist in the brain. A previous study suggested that the social Isolation Stress-induced decrease in pentobarbital sleep in mice was partly due to endogenous substances with an inverse BZD receptor agonist-like property. In this study, we examined the effects of DBI and ODN on pentobarbital sleep in group-housed and socially isolated mice to test the possible involvement of DBI and ODN in a social Isolation-induced decrease in pentobarbital sleep. The socially isolated mice showed significantly shorter durations of pentobarbital (50 mg/kg, intraperitoneally, i.p.) sleep compared to the group-housed animals. When injected intracerebroventricularly (i.c.v.), DBI and ODN (3 and 10 nmol) dose-dependently shortened the pentobarbital-induced sleeping time in group-housed mice at the same dose range, but these peptides had no effect on the sleeping time in socially isolated animals. In contrast, flumazenil (16.5–33 nmol, i.c.v.), a BZD receptor antagonist, reversed the pentobarbital sleeping time in socially isolated mice to the level of group-housed animals without affecting the sleeping time in group-housed animals. The effects of DBI and ODN in group-housed mice were significantly blocked by flumazenil (33 nmol, i.c.v.). Moreover, the effect of flumazenil in socially isolated mice was significantly attenuated by DBI and ODN (10 nmol, i.c.v.). These results suggest that the changes in the activity of DBI and/or ODN are partly involved in the social Isolation-induced decrease in the hypnotic action of pentobarbital in mice.
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Involvement of peripheral type of benzodiazepine receptor in social Isolation Stress-induced decrease in pentobarbital sleep in mice.
Life sciences, 1999Co-Authors: Erbo Dong, Kinzo Matsumoto, Hiroshi WatanabeAbstract:Our previous studies have shown that central-type benzodiazepine (BZD) receptors (CBR) and neurosteroids capable of modulating GABA(A) receptor function are involved in the decrease of pentobarbital (PB)-induced sleep caused by social Isolation Stress in mice. In this study, to further clarify the mechanism underlying this decrease, we investigated the possible involvement of peripheral-type BZD receptors (PBR) which play an important role in neurosteroidogenesis in PB sleep in socially isolated mice. Socially isolated mice showed significantly shorter duration of PB-induced sleep than group-housed animals. When injected intracerebroventricularly (i.c.v.), FGIN-1-27 (FGIN, 25-100 nmol), a selective PBR agonist, and PK11195 (PK, 14-28 nmol), a PBR antagonist, and pregnenolone (PREG, 15-30 nmol), a neurosteroid precursor, dose-dependently normalized the PB sleep in isolated mice without having an effect on the group-housed animals. In contrast, pregnenolone sulfate (PS, 24 nmol), an endogenous neurosteroidal negative allosteric modulator of the GABA(A) receptor, reduced PB sleep in group-housed but not isolated mice. PS, at the same dose, significantly attenuated the effects of FGIN (100 nmol), PK (28 nmol) and PREG (30 nmol) in isolated mice, while FGIN (100 nmol), PK (28 nmol) and pregnenolone (30 nmol) significantly blocked the effect of PS (24 nmol) in group-housed mice. These results suggest that the PBR-mediated decrease in the genesis of neurosteroid(s) possessing a GABA(A) receptor agonistic profile is also partly involved in the down regulation of the GABA(A) receptor following long-term social Isolation and contributes to the decrease of PB-induced sleep in Isolation Stressed mice.
Ravi Bihari Srivastava - One of the best experts on this subject based on the ideXlab platform.
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Disrupting monotony during social Isolation Stress prevents early development of anxiety and depression like traits in male rats
BMC Neuroscience, 2015Co-Authors: Kalpana Barhwal, Sunil Kumar Hota, Mahendra Kumar Thakur, Ravi Bihari SrivastavaAbstract:Background Although there have been several reports on social Isolation induced mood alterations, the independent contribution of monotonous environment in mediating mood alterations has been less studied. In view of the above, the present study is aimed at investigating the relative contribution of monotony towards mood alterations during Isolation Stress. Monotony was induced in a specially designed Isolation chamber in male Sprague-Dawley rats in the presence or absence of Isolation by housing animals singly (SH) or in pairs (PH). Novel objects were introduced to disrupt monotony in singly housed animals (SHNO) or paired housed animals (PHNO). Behavioural alterations were assessed using Open field test (OFT), Elevated Plus Maze (EPM) and Forced Swim Test (FST). Neuro-morphological changes in the CA3 region of hippocampus were studied by cresyl violet and golgi-cox staining. Hippocampal serotonin and 5-hydroxy indole acetic acid (5-HIAA) levels were estimated along with the expression of phospho-insulin like growth factor-1 receptor (pIGF-1R) and phospho cyclic AMP response-element binding protein (pCREB). Serotonin was depleted by administering Para-chlorophenylalanine (PCPA) to a separate PH group (PHPCPA), PHNO group (PHNOPCPA) and SHNO group (SHNOPCPA) to determine the role of serotonin in mediating monotony induced emotional mal-adaptations. Results The results showed anxiety and depression like traits in both PH and SH groups during behavioural test such as OFT, EPM and FST. Pyknosis along with decrease in apical dendritic arborization was observed in the CA3 region of SH group along with decrease in serotonin and reduced expression of pIGF-1R and pCREB. Disrupting monotony through intervention of novel objects in PHNO and SHNO groups ameliorated anxiety and depression like traits and augmented pIGF-1R along with increase in serotonin level. Depletion of hippocampal serotonin level by PCPA administration in PHNOPCPA and SHNOPCPA groups on the other hand resulted in altered mood state despite disruption of monotony by novel objects intervention. Conclusion The findings of our study suggest that monotonous environment independently contributes to impairment in mood state and disrupting monotony by intervention of novel objects during social Isolation prevents mood disorders and emotional maladaptation through up regulation of hippocampal pIGF-1R and increase in serotonin.
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disrupting monotony during social Isolation Stress prevents early development of anxiety and depression like traits in male rats
BMC Neuroscience, 2015Co-Authors: Saroj Kumar Das, Kalpana Barhwal, Sunil Kumar Hota, Mahendra Kumar Thakur, Ravi Bihari SrivastavaAbstract:Background Although there have been several reports on social Isolation induced mood alterations, the independent contribution of monotonous environment in mediating mood alterations has been less studied. In view of the above, the present study is aimed at investigating the relative contribution of monotony towards mood alterations during Isolation Stress. Monotony was induced in a specially designed Isolation chamber in male Sprague-Dawley rats in the presence or absence of Isolation by housing animals singly (SH) or in pairs (PH). Novel objects were introduced to disrupt monotony in singly housed animals (SHNO) or paired housed animals (PHNO). Behavioural alterations were assessed using Open field test (OFT), Elevated Plus Maze (EPM) and Forced Swim Test (FST). Neuro-morphological changes in the CA3 region of hippocampus were studied by cresyl violet and golgi-cox staining. Hippocampal serotonin and 5-hydroxy indole acetic acid (5-HIAA) levels were estimated along with the expression of phospho-insulin like growth factor-1 receptor (pIGF-1R) and phospho cyclic AMP response-element binding protein (pCREB). Serotonin was depleted by administering Para-chlorophenylalanine (PCPA) to a separate PH group (PHPCPA), PHNO group (PHNOPCPA) and SHNO group (SHNOPCPA) to determine the role of serotonin in mediating monotony induced emotional mal-adaptations.
Kalpana Barhwal - One of the best experts on this subject based on the ideXlab platform.
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Early mood behavioral changes following exposure to monotonous environment during Isolation Stress is associated with altered hippocampal synaptic plasticity in male rats
Neuroscience letters, 2015Co-Authors: Saroj Kumar Das, Kalpana Barhwal, Sunil Kumar Hota, Iswar Baitharu, Shashi Bala SinghAbstract:Social Isolation Stress and its effect on mood have been well reported, but the effect of monotony (a state of repetition of events for a considerable period of time without variation) on mood and hippocampal synaptic plasticity needs to be addressed. Present study was conducted on male Sprague-Dawley rats. Singly housed (SH) rats were subjected to monotony Stress by physical, visual and pheromonal separation in specially designed animal segregation chamber. Fluoxetine (a selective serotonin reuptake inhibitor) was administered orally. Behavioral assessment showed anxiety and depression like traits in SH group. Monotony Stress exposure to SH group resulted in increased pyknosis, decreased apical dendritic arborization and increased asymmetric (excitatory) synapses with the corresponding decrease in the symmetric (inhibitory) synapses in the hippocampal CA3 region. Monotonous environment during Isolation Stress also decreased the serotonin level and reduced the expression of synaptophysin and pCREB in the hippocampus. Fluoxetine administration to singly housed rats resulted in amelioration of altered mood along with improvement in serotonin and decrease in excitatory synaptic density but no change in altered inhibitory synaptic density in the hippocampus. These findings suggest that monotony during Isolation contributes to early impairment in mood state by altering hippocampal synaptic density and neuronal morphology.
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Disrupting monotony during social Isolation Stress prevents early development of anxiety and depression like traits in male rats
BMC Neuroscience, 2015Co-Authors: Kalpana Barhwal, Sunil Kumar Hota, Mahendra Kumar Thakur, Ravi Bihari SrivastavaAbstract:Background Although there have been several reports on social Isolation induced mood alterations, the independent contribution of monotonous environment in mediating mood alterations has been less studied. In view of the above, the present study is aimed at investigating the relative contribution of monotony towards mood alterations during Isolation Stress. Monotony was induced in a specially designed Isolation chamber in male Sprague-Dawley rats in the presence or absence of Isolation by housing animals singly (SH) or in pairs (PH). Novel objects were introduced to disrupt monotony in singly housed animals (SHNO) or paired housed animals (PHNO). Behavioural alterations were assessed using Open field test (OFT), Elevated Plus Maze (EPM) and Forced Swim Test (FST). Neuro-morphological changes in the CA3 region of hippocampus were studied by cresyl violet and golgi-cox staining. Hippocampal serotonin and 5-hydroxy indole acetic acid (5-HIAA) levels were estimated along with the expression of phospho-insulin like growth factor-1 receptor (pIGF-1R) and phospho cyclic AMP response-element binding protein (pCREB). Serotonin was depleted by administering Para-chlorophenylalanine (PCPA) to a separate PH group (PHPCPA), PHNO group (PHNOPCPA) and SHNO group (SHNOPCPA) to determine the role of serotonin in mediating monotony induced emotional mal-adaptations. Results The results showed anxiety and depression like traits in both PH and SH groups during behavioural test such as OFT, EPM and FST. Pyknosis along with decrease in apical dendritic arborization was observed in the CA3 region of SH group along with decrease in serotonin and reduced expression of pIGF-1R and pCREB. Disrupting monotony through intervention of novel objects in PHNO and SHNO groups ameliorated anxiety and depression like traits and augmented pIGF-1R along with increase in serotonin level. Depletion of hippocampal serotonin level by PCPA administration in PHNOPCPA and SHNOPCPA groups on the other hand resulted in altered mood state despite disruption of monotony by novel objects intervention. Conclusion The findings of our study suggest that monotonous environment independently contributes to impairment in mood state and disrupting monotony by intervention of novel objects during social Isolation prevents mood disorders and emotional maladaptation through up regulation of hippocampal pIGF-1R and increase in serotonin.
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disrupting monotony during social Isolation Stress prevents early development of anxiety and depression like traits in male rats
BMC Neuroscience, 2015Co-Authors: Saroj Kumar Das, Kalpana Barhwal, Sunil Kumar Hota, Mahendra Kumar Thakur, Ravi Bihari SrivastavaAbstract:Background Although there have been several reports on social Isolation induced mood alterations, the independent contribution of monotonous environment in mediating mood alterations has been less studied. In view of the above, the present study is aimed at investigating the relative contribution of monotony towards mood alterations during Isolation Stress. Monotony was induced in a specially designed Isolation chamber in male Sprague-Dawley rats in the presence or absence of Isolation by housing animals singly (SH) or in pairs (PH). Novel objects were introduced to disrupt monotony in singly housed animals (SHNO) or paired housed animals (PHNO). Behavioural alterations were assessed using Open field test (OFT), Elevated Plus Maze (EPM) and Forced Swim Test (FST). Neuro-morphological changes in the CA3 region of hippocampus were studied by cresyl violet and golgi-cox staining. Hippocampal serotonin and 5-hydroxy indole acetic acid (5-HIAA) levels were estimated along with the expression of phospho-insulin like growth factor-1 receptor (pIGF-1R) and phospho cyclic AMP response-element binding protein (pCREB). Serotonin was depleted by administering Para-chlorophenylalanine (PCPA) to a separate PH group (PHPCPA), PHNO group (PHNOPCPA) and SHNO group (SHNOPCPA) to determine the role of serotonin in mediating monotony induced emotional mal-adaptations.
Sunil Kumar Hota - One of the best experts on this subject based on the ideXlab platform.
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Early mood behavioral changes following exposure to monotonous environment during Isolation Stress is associated with altered hippocampal synaptic plasticity in male rats
Neuroscience letters, 2015Co-Authors: Saroj Kumar Das, Kalpana Barhwal, Sunil Kumar Hota, Iswar Baitharu, Shashi Bala SinghAbstract:Social Isolation Stress and its effect on mood have been well reported, but the effect of monotony (a state of repetition of events for a considerable period of time without variation) on mood and hippocampal synaptic plasticity needs to be addressed. Present study was conducted on male Sprague-Dawley rats. Singly housed (SH) rats were subjected to monotony Stress by physical, visual and pheromonal separation in specially designed animal segregation chamber. Fluoxetine (a selective serotonin reuptake inhibitor) was administered orally. Behavioral assessment showed anxiety and depression like traits in SH group. Monotony Stress exposure to SH group resulted in increased pyknosis, decreased apical dendritic arborization and increased asymmetric (excitatory) synapses with the corresponding decrease in the symmetric (inhibitory) synapses in the hippocampal CA3 region. Monotonous environment during Isolation Stress also decreased the serotonin level and reduced the expression of synaptophysin and pCREB in the hippocampus. Fluoxetine administration to singly housed rats resulted in amelioration of altered mood along with improvement in serotonin and decrease in excitatory synaptic density but no change in altered inhibitory synaptic density in the hippocampus. These findings suggest that monotony during Isolation contributes to early impairment in mood state by altering hippocampal synaptic density and neuronal morphology.
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Disrupting monotony during social Isolation Stress prevents early development of anxiety and depression like traits in male rats
BMC Neuroscience, 2015Co-Authors: Kalpana Barhwal, Sunil Kumar Hota, Mahendra Kumar Thakur, Ravi Bihari SrivastavaAbstract:Background Although there have been several reports on social Isolation induced mood alterations, the independent contribution of monotonous environment in mediating mood alterations has been less studied. In view of the above, the present study is aimed at investigating the relative contribution of monotony towards mood alterations during Isolation Stress. Monotony was induced in a specially designed Isolation chamber in male Sprague-Dawley rats in the presence or absence of Isolation by housing animals singly (SH) or in pairs (PH). Novel objects were introduced to disrupt monotony in singly housed animals (SHNO) or paired housed animals (PHNO). Behavioural alterations were assessed using Open field test (OFT), Elevated Plus Maze (EPM) and Forced Swim Test (FST). Neuro-morphological changes in the CA3 region of hippocampus were studied by cresyl violet and golgi-cox staining. Hippocampal serotonin and 5-hydroxy indole acetic acid (5-HIAA) levels were estimated along with the expression of phospho-insulin like growth factor-1 receptor (pIGF-1R) and phospho cyclic AMP response-element binding protein (pCREB). Serotonin was depleted by administering Para-chlorophenylalanine (PCPA) to a separate PH group (PHPCPA), PHNO group (PHNOPCPA) and SHNO group (SHNOPCPA) to determine the role of serotonin in mediating monotony induced emotional mal-adaptations. Results The results showed anxiety and depression like traits in both PH and SH groups during behavioural test such as OFT, EPM and FST. Pyknosis along with decrease in apical dendritic arborization was observed in the CA3 region of SH group along with decrease in serotonin and reduced expression of pIGF-1R and pCREB. Disrupting monotony through intervention of novel objects in PHNO and SHNO groups ameliorated anxiety and depression like traits and augmented pIGF-1R along with increase in serotonin level. Depletion of hippocampal serotonin level by PCPA administration in PHNOPCPA and SHNOPCPA groups on the other hand resulted in altered mood state despite disruption of monotony by novel objects intervention. Conclusion The findings of our study suggest that monotonous environment independently contributes to impairment in mood state and disrupting monotony by intervention of novel objects during social Isolation prevents mood disorders and emotional maladaptation through up regulation of hippocampal pIGF-1R and increase in serotonin.
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disrupting monotony during social Isolation Stress prevents early development of anxiety and depression like traits in male rats
BMC Neuroscience, 2015Co-Authors: Saroj Kumar Das, Kalpana Barhwal, Sunil Kumar Hota, Mahendra Kumar Thakur, Ravi Bihari SrivastavaAbstract:Background Although there have been several reports on social Isolation induced mood alterations, the independent contribution of monotonous environment in mediating mood alterations has been less studied. In view of the above, the present study is aimed at investigating the relative contribution of monotony towards mood alterations during Isolation Stress. Monotony was induced in a specially designed Isolation chamber in male Sprague-Dawley rats in the presence or absence of Isolation by housing animals singly (SH) or in pairs (PH). Novel objects were introduced to disrupt monotony in singly housed animals (SHNO) or paired housed animals (PHNO). Behavioural alterations were assessed using Open field test (OFT), Elevated Plus Maze (EPM) and Forced Swim Test (FST). Neuro-morphological changes in the CA3 region of hippocampus were studied by cresyl violet and golgi-cox staining. Hippocampal serotonin and 5-hydroxy indole acetic acid (5-HIAA) levels were estimated along with the expression of phospho-insulin like growth factor-1 receptor (pIGF-1R) and phospho cyclic AMP response-element binding protein (pCREB). Serotonin was depleted by administering Para-chlorophenylalanine (PCPA) to a separate PH group (PHPCPA), PHNO group (PHNOPCPA) and SHNO group (SHNOPCPA) to determine the role of serotonin in mediating monotony induced emotional mal-adaptations.
