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Chronic variable stress affects hippocampal neurotrophic factor gene expression in the novelty-seeking phenotype
Title
Chronic variable stress affects hippocampal neurotrophic factor gene expression in the novelty-seeking phenotype: epigenetic regulation.
Creator
Oztan, Ozge., Charles E. Schmidt College of Medicine
Abstract/Description
Experimentally naive rats exhibit varying degrees of novelty exploration. Some rats display high rates of locomotor reactivity to novelty (high responders; HR), and others display low rates (low responders; LR). The novelty-seeking phenotype (LRHR) is introduced as a model of stress responsiveness. In this thesis I examined effects of chronic variable physical and social stress or control handling on the levels of various neurotrophins in the hippocampus, and changes in mossy fibre terminal...
Show moreExperimentally naive rats exhibit varying degrees of novelty exploration. Some rats display high rates of locomotor reactivity to novelty (high responders; HR), and others display low rates (low responders; LR). The novelty-seeking phenotype (LRHR) is introduced as a model of stress responsiveness. In this thesis I examined effects of chronic variable physical and social stress or control handling on the levels of various neurotrophins in the hippocampus, and changes in mossy fibre terminal fields in LRHR rats. A positive correlation is seen between histone deacetylase 2 and brain-derived neurotrophic factor (BDNF) levels both of which are oppositely regulated in LRHR CA3 fields in response to chronic social stress. Increase in BDNF levels in CA3 field accompanied increase in supra-pyramidal mossy fibre terminal field size (SP-MF) in HRs, and decrease in BDNF levels accompanied decrease in SP-MF volume in LRs. Epigenetic regulation of neurotrophic support underlying these structural changes is discussed.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/215290
Subject Headings
Rats as laboratory animals, Cellular signal transduction, Gene expression, Hippocampus (Brain), Physiology, Neural transmission, Genetic regulation
Format
Document (PDF)
Effects of adolescent stress on depressive- and anxiety-like behaviors and hippocampal mossy fibre-CA3 remodeling in the novelty-seeking phenotype
Title
Effects of adolescent stress on depressive- and anxiety-like behaviors and hippocampal mossy fibre-CA3 remodeling in the novelty-seeking phenotype: implications for epigenetic regulation of the BDNF gene.
Creator
Oztan, Ozge., Charles E. Schmidt College of Medicine, Department of Biomedical Science
Abstract/Description
Experimentally naive rats show variance in their locomotor reactivity to novelty, some displaying higher (HR) while others displaying lower (LR) reactivity, associated with vulnerability to stress. LRHR phenotype is proposed as an antecedent to the development of stress hyper responsiveness. Results presented here show emergence of antidepressive-like behavior following peripubertal-juvenile exposure to chronic variable physical (CVP) and chronic variable social stress (CVS) in HR rats, and...
Show moreExperimentally naive rats show variance in their locomotor reactivity to novelty, some displaying higher (HR) while others displaying lower (LR) reactivity, associated with vulnerability to stress. LRHR phenotype is proposed as an antecedent to the development of stress hyper responsiveness. Results presented here show emergence of antidepressive-like behavior following peripubertal-juvenile exposure to chronic variable physical (CVP) and chronic variable social stress (CVS) in HR rats, and depressive-like behavior following CVP in the LRs. The antidepressive-like behavior in HR rats was accompanied by increased levels of acetylated Histone3 (acH3) and acetylated Histone4 (acH4) at the hippocampal brain-derived neurotrophic factor (BDNF) P2 and P4 promoters respectively. This effect may mediate increased mossy fibre (MF) terminal field size, particularly the suprapyramidal mossy fibre projection volume (SP-MF), in the HR animals following both stress regimens. These findings show that chronic variable stress during adolescence induces individual differences in molecular, neuromorphological and behavioral parameters between LRs and HRs, which provides further evidence that individual differences in stress responsiveness is an important factor in resistance or vulnerability to stress-induced depression and/or anxiety.
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Date Issued
2013
PURL
http://purl.flvc.org/fcla/dt/3360950
Subject Headings
Rats as laboratory animals, Anxiety in adolescence, Depression in adolescence, Stress (Psychology), Cellular signal transduction, Hippocampus (Brain), Physiology, Genetic regulation, Gene expression
Format
Document (PDF)
Hippocampal CA1 activation during object memory encoding in the novel object recognition task
Title
Hippocampal CA1 activation during object memory encoding in the novel object recognition task.
Creator
Cinalli, David A., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description
Transcription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal...
Show moreTranscription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal hippocampus in mice following two variations of the novel object recognition (NOR) task. Results suggest mice that acquired strong object memory showed significant hippocampal activation. In mice that acquired weak object memory, hippocampal activation was not significantly different from controls. Arc expression was also examined in other hippocampal sub-regions, as well as in the perirhinal cortex. These results suggest that the mice must acquire a threshold amount of object information before the hippocampal CA1 region is engaged.
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Date Issued
2015
PURL
http://purl.flvc.org/fau/fd/FA00004436, http://purl.flvc.org/fau/fd/FA00004436
Subject Headings
Association of ideas, Cellular control mechanisms, Cellular signal transduction, Episodic memory, Hippocampus (Brain) -- Physiology, Human information processing, Mice as laboratory animals
Format
Document (PDF)
Of Mice, Men and Memories: The Role of the Rodent Hippocampus in Object Recognition
Title
Of Mice, Men and Memories: The Role of the Rodent Hippocampus in Object Recognition.
Creator
Cohen, Sarah J., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description
Establishing appropriate animal models for the study of human memory is paramount to the development of memory disorder treatments. Damage to the hippocampus, a medial temporal lobe brain structure, has been implicated in the memory loss associated with Alzheimer’s disease and other dementias. In humans, the role of the hippocampus is largely defined; yet, its role in rodents is much less clear due to conflicting findings. To investigate these discrepancies, an extensive review of the rodent...
Show moreEstablishing appropriate animal models for the study of human memory is paramount to the development of memory disorder treatments. Damage to the hippocampus, a medial temporal lobe brain structure, has been implicated in the memory loss associated with Alzheimer’s disease and other dementias. In humans, the role of the hippocampus is largely defined; yet, its role in rodents is much less clear due to conflicting findings. To investigate these discrepancies, an extensive review of the rodent literature was conducted, with a focus on studies that used the Novel Object Recognition (NOR) paradigm for testing. The total amount of time the objects were explored during training and the delay imposed between training and testing seemed to determine hippocampal recruitment in rodents. Male C57BL/6J mice were implanted with bilateral dorsal CA1 guide cannulae to allow for the inactivation of the hippocampus at discrete time points in the task. The results suggest that the rodent hippocampus is crucial to the encoding, consolidation and retrieval of object memory. Next, it was determined that there is a delay-dependent involvement of the hippocampus in object memory, implying that other structures may be supporting the memory prior to the recruitment of hippocampus. In addition, when the context memory and object memory could be further dissociated, by altering the task design, the results imply a necessary role for the hippocampus in the object memory, irrespective of context. Also, making the task more perceptually demanding, by requiring the mice to perform a two-dimensional to three-dimensional association between stimuli, engaged the hippocampus. Then, in the traditional NOR task, long and short training exploration times were imposed to determine brain region activity for weak and strong object memory. The inactivation and immunohistochemistry findings imply weak object memory is perirhinal cortex dependent, while strong object memory is hippocampal-dependent. Taken together, the findings suggest that mice, like humans, process object memory on a continuum from weak to strong, recruiting the hippocampus conditionally for strong familiarity. Confirming this functional similarity between the rodent and human object memory systems could be beneficial for future studies investigating memory disorders.
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Date Issued
2016
PURL
http://purl.flvc.org/fau/fd/FA00004580
Subject Headings
Memory--Research., Mice as laboratory animals., Hippocampus (Brain)--Physiology., Episodic memory., Neurotransmitter receptors., Cellular control mechanisms., Cellular signal transduction., Human information processing.
Format
Document (PDF)