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Examining The Role Of Chloride Homeostasis And Pge2 Signaling In The Neuroendocrine Stress Response To Inflammation, Samuel A. Mestern
Examining The Role Of Chloride Homeostasis And Pge2 Signaling In The Neuroendocrine Stress Response To Inflammation, Samuel A. Mestern
Electronic Thesis and Dissertation Repository
The brain senses inflammatory signals and drives the release of glucocorticoids (GCs) — potent immunosuppressants — via the activation of the hypothalamic-pituitary-adrenal (HPA) axis. This inflammation-induced HPA axis activation is largely mediated by prostaglandin E2 (PGE2), acting on two subtypes of the PGE2 receptor, EP1 and EP3. Recently, our group revealed EP3 signaling mechanisms that excite HPA axis regulatory neurons. This thesis sought to tease out the remaining EP1 signaling mechanisms. Considering that the excitability of HPA axis regulatory neurons is constrained by GABAA receptor-mediated synaptic inhibition that relies on low-level intracellular Cl-. We hypothesized that PGE2-EP1 …
Weathering The Storm: Physiological And Behavioural Responses Of White-Throated Sparrows To Inclement Weather Cues, Andrea C. Boyer
Weathering The Storm: Physiological And Behavioural Responses Of White-Throated Sparrows To Inclement Weather Cues, Andrea C. Boyer
Electronic Thesis and Dissertation Repository
Changes in weather patterns and extreme weather events are becoming more common with the onset of climate change. This predicted increase in severe weather globally is alarming and it draws concern for the adaptability and ultimate survival of many species. It is clear that birds are able to cope with and respond to inclement weather with physiological and behavioural responses in many circumstances, but as environmental conditions become more severe, the adaptive coping responses of many species may be pushed to their limit. As such, it is important to understand the effects that such changes in environmental conditions will have …
Uncovering A Mystery Of The Isoflavonoid Metabolon: Identification And Characterization Of The Arogenate Dehydratase Gene Family In Soybean, Kelsey Pannunzio
Uncovering A Mystery Of The Isoflavonoid Metabolon: Identification And Characterization Of The Arogenate Dehydratase Gene Family In Soybean, Kelsey Pannunzio
Electronic Thesis and Dissertation Repository
Soybean (Glycine max) is a vastly important, multi-billion dollar global commodity; but this crop’s yields are under threat from the pathogen Phytophthora sojae, which causes extensive stem and root rot in soybean crops. Isoflavonoids, a metabolite class unique to legumes, are a promising research target to combat P. sojae. Isoflavonoids are released as phytoalexins in response to stress, and also facilitate interactions with nitrogen-fixing rhizobial bacteria through nodule formation. An isoflavonoid biosynthesis metabolon was discovered in soybean through co-immunoprecipitation, anchored to the endoplasmic reticulum by isoflavone synthase (IFS) and Cinnamate 4-hydroxylase, two cytochrome P450 enzymes. One of the …
The Effects Of Perceived Predation Threat On Stress Response And Memory In Birds, Chlöe S. N. Carter
The Effects Of Perceived Predation Threat On Stress Response And Memory In Birds, Chlöe S. N. Carter
Electronic Thesis and Dissertation Repository
This study examined how perception of predator cues, across three sensory modalities, affects physiology and behaviour of songbirds. I hypothesized that the perception of predator threat would elicit physiological and behavioural responses in both acute and chronic exposure conditions. My first study examined the responses of wild-caught black-capped chickadees (Poecile atricapillus) and house sparrows (Passer domesticus), as well as lab-bred zebra finches (Taeniopygia guttata), to acute predation cue exposure by coding video recorded behaviour and corticosterone analysis. My second study examined changes in black-capped chickadees’ foraging behaviour and memory retention after chronic exposure to …
Synaptic Correlates For Stress Sensitization, Julia Kj Sunstrum
Synaptic Correlates For Stress Sensitization, Julia Kj Sunstrum
Electronic Thesis and Dissertation Repository
The stress response is essential for survival, but it can be detrimental when persistently activated during chronic stress. Therefore, the magnitude of the stress response must be finely-tuned in order to be adaptive. Indeed, an animal’s stress response system normally undergoes habituation that decreases responses to a repeated, familiar stressor. Importantly, the same animal still responds normally, or even becomes sensitized, to an unfamiliar (novel) stressor. This indicates that chronic stress simultaneously induces two opposing types of plasticity, one that underlies habituated responses and another that drives sensitized responses. The activation of the hypothalamic-pituitary-adrenal (HPA) axis — a hallmark of …
Early Life Immune And Physical Stress Directly Influences Anxiety-Like Behaviour In Adolescent Rats: Examining Sex Differences, Jordan M. Ward
Early Life Immune And Physical Stress Directly Influences Anxiety-Like Behaviour In Adolescent Rats: Examining Sex Differences, Jordan M. Ward
Electronic Thesis and Dissertation Repository
This thesis examined the effects of neonatal acute immune activation with the endotoxin, lipopolysaccharide (LPS) on postnatal days 3 and 5 on adolescent anxiety-like behaviour in rats before and after a stress period. Previous research has shown that adults rats exposed to LPS during the neonatal stage show anxiety-like behaviour following a period of stress. This thesis investigated this effect in adolescence. The present results showed significantly higher anxiety-like behaviour in saline controls, and a potential neuroprotective effect of low dose LPS (15 µg/kg) contrary to what was reported in adult rats. As well, a phase of stressful, aversive conditioning …
Corticotropin Releasing Factor Receptor Type 1 Signaling In Epilepsy And Traumatic Brain Injury, V V Chakravarthi Narla
Corticotropin Releasing Factor Receptor Type 1 Signaling In Epilepsy And Traumatic Brain Injury, V V Chakravarthi Narla
Electronic Thesis and Dissertation Repository
Stress increases the frequency by which epileptic seizures occur. Corticotropin-releasing factor (CRF) coordinates neuroendocrine, autonomic and behavioral response to stress. This thesis sought to study the cellular and molecular mechanisms by which CRF regulates the activity of neural circuits in the piriform cortex (PC) in normal and epileptic states. The PC is richly innervated by CRF and 5-HT containing axons arising from the central amygdala and raphe nucleus. CRFR1 and 5-HT2A/CRs have been shown to interact in a manner where CRFR activation subsequently potentiates the activity of 5-HT2A/CRs. The first purpose of this thesis was …
Planting The Chalcone Reductase Family Tree: Identification And Characterization Of Chalcone Reductase Genes In Soybean, Caroline Julia Sepiol
Planting The Chalcone Reductase Family Tree: Identification And Characterization Of Chalcone Reductase Genes In Soybean, Caroline Julia Sepiol
Electronic Thesis and Dissertation Repository
Soybean (Glycine max [L.] Merr) is an important crop grown in Canada, generating $2.4 billion in sales. Though this number may be promising, soybean farmers lose about $50 million worth of yield annually due to root and stem rot disease caused by Phytophthora sojae. Many strategies have been developed to combat the infection; however, these methods are prohibitively expensive. A ‘cost effective’ approach to this problem is to select a trait naturally found in soybean that can increase resistance. One such trait is the increased production of root glyceollins. One of the key enzymes exclusively involved in glyceollin …
Associations Between Hypothalamic-Pituitary-Adrenal Axis System Gene Variants And Cortisol Reactivity In Preschoolers: Main Effects And Gene-Environment Interactions, Haroon I. Sheikh
Electronic Thesis and Dissertation Repository
Exposure to stressful events during early development has consistently been shown to produce long lasting effects on the hypothalamic-pituitary-adrenal (HPA) axis, which may increase vulnerability to mood and anxiety disorders. Recently reported genetic association studies indicate that these disorders may be influenced, in part, by gene-environment interactions (GxE) involving polymorphisms within the corticotrophin-releasing hormone and monoaminergic system genes. However, little is known about how genetic variants and life stress work to shape children’s neuroendocrine reactivity and emerging symptoms. Therefore, the aim of this thesis is to examine main effects of candidate genes and GxE on the neuroendocrine stress response and …
Song As An Honest Indicator Of Developmental Stress In Song Sparrows, Kimberly L. Schmidt
Song As An Honest Indicator Of Developmental Stress In Song Sparrows, Kimberly L. Schmidt
Electronic Thesis and Dissertation Repository
The Developmental Stress Hypothesis proposes that the honesty of birdsong is maintained by costs incurred during development, such that song in adulthood reflects exposure to early-life stressors. The purpose of this thesis was to provide a rigorous test of the Developmental Stress Hypothesis in song sparrows (Melospiza melodia). My three objectives were to determine the long-term effects of early-life stress on: 1) physiological traits (Chapters 2, 3, and 4); 2) male song production (Chapter 5); and 3) the response of females to song (Chapter 6). Nestlings were hand-reared in captivity under one of three treatment conditions: control, food …