Physiology Commons^™

The Effects Of Intracerebroventricular Leptin On Milk Availability In Lactating Rats, Brittany Lynita Moore

Electronic Theses and Dissertations

Reports have linked energy balance along with adipocyte derived leptin action to improved fertility. Recent evidence indicates that leptin hormone is present in breast milk and leptin receptors are well expressed in mammary epithelial cells. The hypothesis that insufficiency of leptin restraint in the hypothalamus may underlie infertility in rodents and the failure of lactating breast to express adequate amount of milk was tested. Female Sprague-Dawley rats were injected leptin through intracerebroventricular cannulation (ICVC) of the third ventricle. Female rats were mated with stud males and observed throughout gestation. Compared to the control groups, leptin treatment increased prolactin levels in …

The Cost Of Ethanol Synthesis During Recovery From Exhaustive Exercise In Grass Carp (Ctenopharyngodon Idella), Simon A. Bradford

Electronic Thesis and Dissertation Repository

Grass carp (Ctenopharyngodon idella) reduce white muscle glycogen (~14 µmol glucosyl units/g wet tissue) in response to exhaustive exercise. This reduction results in a small increase in muscle lactate (~9 µmol/g wet tissue) and a larger increase in muscle ethanol (~30 µmol/g wet tissue). Tissue-specific and whole-body measures of glycogen, ethanol and lactate confirm that ethanol is the major “anaerobic” glycolytic end-product. Additionally, while peak muscle and blood ethanol levels occur immediately post-exercise, the excretion of ethanol to the environment is delayed, occurring over a 30-minute period beginning ~105 minutes following exercise. As the total amount of ethanol …

Long-Term Depression Of Excitatory Inputs To Gabaergic Neurons In The Ventral Tegmental Area, Philip J. Sandoval

Theses and Dissertations

Dopamine cells within the ventral tegmental area of the brain are involved in motivation and reward. Drugs of abuse target these dopamine cells altering their activity and plasticity resulting in addiction. While dopamine cell activity is primarily involved in addiction, the GABA neurons in the VTA have also been shown to have an indirect role. By decreasing the activity of the inhibitory GABA inputs onto dopamine neurons abusive drugs can indirectly increase dopamine cell activity resulting in addictive behaviors. However, although GABA neurons are important in the perception of reward, much less is known about how the excitatory inputs to …

Theta Dynamics: Speed, Acceleration And Contribution To Cognition, Lauren L. Long

Master's Theses

No abstract provided.

Neuromuscular Function Following Lengthening Contractions, Geoffrey A. Power

Electronic Thesis and Dissertation Repository

Unaccustomed lengthening contractions have been shown to impair muscle function - however little is known regarding this impairment on muscle power - specifically, the velocity component of power during voluntary contractions in humans. The four studies presented in my thesis investigated power-loss following lengthening contractions in healthy young and old women and young men.

The purpose of Study 1 was to determine reliability of velocity-dependent power of the dorsiflexors using the isotonic mode of the Biodex Dynamometer. I determined the isotonic mode is reliable and can be used to track changes in velocity and power following fatigue and lengthening contractions. …

Hormonal And Morphological Aspects Of Growth And Sexual Maturation In Wild-Caught Male Vervet Monkeys (Chlorocebus Aethiops Pygerythrus), Tegan J. Gaetano

Theses and Dissertations

Knowledge of baseline changes in testosterone (T) and other androgens is central to both investigations of morphological, physiological, and behavioral correlates of inter-individual variation in the timing and shape of key events and transitions over the life course and questions of the evolution of species-specific schedules of maturation in primates. T represents an important determinant of spermatogenesis in male mammals and plays a central role in the expression of male sexual behavior and the development of secondary sex characteristics. This research integrates hormonal and morphometric methods to determine age-related changes in fecal testosterone (fT) metabolites and morphological markers of sexual …

Acute Exercise And Its Effect On Cognitive Performance In Sleep Deprived Individuals: A Review Of Literature., Jennifer Nicole Miller

Undergraduate Honors Theses

This literature review observes seven different studies that researched the effects of exercise on some measure of cognitive or psychological performance when sleep deprived. The purpose of this review is to consolidate the results of various exercise protocols on the effects of sleep deprivation to make a general conclusion regarding the effect on cognition. This will give insight into the future of research regarding how exercise may combat performance decrements seen when sleep deprived. There are several inconsistencies among current research concerning exercise and sleep deprivation; a standard needs to be created so the results of these studies can be …

House Finches, Carpodacus Mexicanus: Hormones, Stress, And Song Control Regions, Katherine Olivia Ganster

Master's Theses

Song production in songbirds is controlled by parts of the brain known as the song control regions (SCRs). During spring, gonads increase in size, males sing to attract mates, and SCRs become larger. This neuroplasticity is controlled by the change in day length and increased plasma testosterone (T) levels. Plasma T can be reduced by stress through the production of corticosterone (CORT), through the production of beta-endorphin, or through direct effects on the testes via the nervous system. We determined the T, estradiol, and CORT hormonal profiles of wild House Finches by capturing and sampling blood from the finches every …

Cold Tolerance Of Each Life Stage Of The Sub-Alpine Willow Leaf Beetle, Chrysomela Aeneicollis, Evelyn C. Boychuk

Electronic Thesis and Dissertation Repository

To understand the potential effects of climate change on the sub-alpine willow leaf beetle, the cold tolerance strategy and mechanisms involved in cold tolerance were investigated for all life stages. Microhabitat choice and microclimate temperatures within each microhabitat were related to median lethal temperature for each life stage. Summer active and quiescent adults are freeze tolerant, eggs and pupae are freeze avoidant and all larval stages are chill susceptible. Quiescent adults accumulated the highest concentration of glycerol (~24 mM) and haemolymph osmolality (875 mOsm). Haemolymph from pupae had angular crystals suggestive of antifreeze agent activity, but this was absent in …

Novel Strategies To Improve Metabolic Parameters And Precondition Diabetic Hearts Against Ischemia/Reperfusion Injury, Amit Varma

Theses and Dissertations

Insulin resistance and chronic hyperglycemia promote vascular damage, increase circulating levels of inflammatory cytokines and lead to increased morbidity and mortality. MicroRNAs (miRs) -103/107 have been shown to negatively regulate insulin sensitivity and glucose homeostasis. Based on complimentary binding profiles, the downstream target gene of miR-103/107 is caveolin-1 (Cav-1). We hypothesized that daily administration of the phosphodiesterase-5 inhibitor tadalafil (TAD) ± the curcumin analogue (HO-3867) will attenuate inflammation, improve metabolic parameters and reduce infarct size after ischemia/reperfusion injury (IRI). Furthermore, we propose that TAD therapy will reduce myocardial expression of miR-103/107 and increase mRNA and protein levels of its target …

Ion Homeostasis And Variation In Low Temperature Performance In The Fall And Spring Field Crickets (Orthoptera: Gryllidae), Litza E. Coello Alvarado

Electronic Thesis and Dissertation Repository

Low temperature performance affects the geographical distribution of insects. The lower critical temperature limits of chill-susceptible insects are likely determined by failure of ion and water balance at low temperature. I used phenotypic plasticity in the cold tolerance of Gryllus pennsylvanicus, and the naturally higher cold tolerance of Gryllus veletis to test the hypothesis that variation in low temperature performance is accompanied by variation in ion and water homeostasis at low temperatures. Low temperature acclimation and cold adaptation enhanced performance at low temperatures. Groups with higher cold tolerance had an enhanced ability to prevent or mitigate the migration of hemolymph …

Regulation Of Sensory Neurogenesis In The Trigeminal Placode: Notch Pathway Genes, Pax3 Isoforms, And Wnt Ligands, Jason Samuel Adams

Theses and Dissertations

This dissertation is divided into three chapters, each discussing the study of different regulatory molecules involved in sensory neurogenesis occurring in the trigeminal placode. Chapter one is a spatiotemporal description of Notch pathway genes in chick opV placode by stage-specific expression analysis, showing expression of many Notch pathway genes and effectors in the opV placode. Notch pathway gene expression is primarily confined to the ectoderm with highest expression of these genes at the beginning stages of peak neuronal differentiation. This information preceded studies of the functional roles that Notch signaling has in the opV placode and how it may affect …

Regulation Of Excitation-Contraction And Excitation-Transcription Coupling In Gastrointestinal Smooth Muscle By Caveolin-1, Sayak Bhattacharya

Theses and Dissertations

Caveolae are integral part of the smooth muscle membrane and caveolins, the defining proteins of caveolae, act as scaffolding proteins for several G protein-coupled receptor signaling molecules and regulate cellular signaling through direct and indirect interactions with signaling proteins. Caveolin-1 is the predominant isoform in the smooth muscle and drives the formation of caveolae. However, little is known about the role of caveolin-1 in the regulation of excitation-contraction and excitation-transcription coupling in gastrointestinal smooth muscle. In the present study we have characterized muscarinic m2 and m3 receptor signaling in gastric smooth muscle and tested the hypothesis that caveolin-1 positively regulates …

The Role Of Glycogen Synthase Kinase 3 Beta In Skeletal Development, J. Ryan Gillespie

Electronic Thesis and Dissertation Repository

Glycogen Synthase Kinase 3 beta (GSK-3b) is an important node of regulation in many cellular signaling pathways including insulin and Wnt. Previous work has shown that ubiquitous deletion of GSK-3b is lethal and causes various skeletal abnormalities, but it is not known whether these defects are skeleton-intrinsic. A second GSK-3 protein which shares almost complete homology, GSK-3a, has been shown to have completely overlapping roles with the b form in some cases and independent functions in other cases. Therefore examination of the role of GSK-3b in skeletal development is very poignant.

To examine the role of GSK-3b in skeletal development …

Mutant P53 Regulation Of Cxc-Chemokine Expression In Head And Neck Squamous Cell Carcinoma, Brittany Field

Theses and Dissertations

Head and neck squamous cell carcinoma (HNSCC) is the 6th most common type of cancer in the western hemisphere with a five-year survival rate of only 50% for patients with a localized tumor, which decreases significantly to as low as 5% for those patients with tumors that have metastasized to distant sites of the body. It has been found that both mutant p53 and epidermal growth factor receptor (EGFR) signaling pathways function to increase the expression of CXCL5, which has been identified as a key mediator in the process of tumor metastasis. Previous data from our lab suggested that the …

Gβγ Acts At An Inter-Subunit Cleft To Activate Girk1 Channels, Rahul Mahajan

Theses and Dissertations

Heterotrimeric guanine nucleotide-binding proteins (G-proteins) consist of an alpha subunit (Gα) and the dimeric beta-gamma subunit (Gβγ). The first example of direct cell signaling by Gβγ was the discovery of its role in activating G-protein regulated inwardly rectifying K+ (GIRK) channels which underlie the acetylcholine-induced K+ current responsible for vagal inhibition of heart rate. Published crystal structures have provided important insights into the structures of the G-protein subunits and GIRK channels separately, but co-crystals of the channel and Gβγ together remain elusive and no specific reciprocal residue interactions between the two proteins are currently known. Given the absence of direct …

Neuroprotective Effects Of Long-Term Endurance Training On The Cortical Autonomic Network In The Aging Brain, Torri A. Luchyshyn

Electronic Thesis and Dissertation Repository

This study tested whether long-term endurance training in older adults (ET; n = 15, 55 ± 4 years, relative VO₂max = 50 ± 8 ml/kg/min) would alter cardiovagal control and preserve the cortical autonomic network compared to age-matched controls (CON; n = 15, 56 ± 4 years, relative VO₂max = 37 ± 9 ml/kg/min). The hypothesis predicts 1) altered deactivation patterns of the ventral medial prefrontal cortex (vMPFC) in response to isometric hand grip (IHG) and 2) greater indices of cardiovagal control; a) increased baroreflex sensitivity at rest, b) greater heart rate change (ΔHR) and c) …

Reliability Of Flow-Mediated Dilation Measures In The Popliteal Artery And Implications For Use In Clinical And Research Practices, Kaitlin M. Mclay

Electronic Thesis and Dissertation Repository

PURPOSE: The aim of the present study was to assess the internal consistency and stability reliability of flow-mediated dilation (FMD) in the popliteal artery and to investigate the effect of occlusion pressure on the FMD response. METHODS: A series of FMD tests were performed on ten healthy young adult males to assess reliability. Ultrasound-derived artery diameter of the popliteal was measured and FMD was calculated as the percent change in diameter from baseline. RESULTS: FMD measurements for intra- and interday comparisons demonstrated poor reliability (Repeatability 5.62 and 4.82%, Intraclass correlation coefficient [ICC] 0.36 and 0.25, respectively). Repeatability values were as …

Environmental Physiology Of Flight In Migratory Birds, Alexander R. Gerson

Electronic Thesis and Dissertation Repository

Migratory birds complete amazing journeys between their breeding and wintering grounds. Each journey comprises a series of flights that last hours to days, followed by stopovers where fuel stores are replenished. Despite the long flights undertaken by migratory birds, where respiratory water losses are high for extended periods of time, birds are not dehydrated after flight. My studies demonstrate that birds maintain hydration by modulating rates of endogenous water production in response to rates of water loss. In resting, water restricted house sparrows (Passer domesticus) I used quantitative magnetic resonance body composition analysis (QMR) and hygrometry to demonstrate that stressed …

The Distribution And Functional Properties Of Pmld-Linked Cx47 Mutations On Cx47/Cx47 Homotypic And Cx47/Cx43 Heterotypic Gap Junctions, Mi Seong Kim

Electronic Thesis and Dissertation Repository

Gap junctions (GJ) allow direct intercellular communication, and consist of connexins (Cx). In the mammalian central nervous system, oligodendrocytes express Cx29, Cx32 and Cx47, whereas astrocytes express Cx26, Cx30 and Cx43. Cx47/Cx47 GJs couple oligodendrocytes, and Cx47/Cx43 channels are the primary heterotypic GJs at oligodendrocyte/astrocyte junctions. Interestingly, mutations in Cx47 have been linked to central hypomyelinating Pelizaeus Merzbacher-like Disease (PMLD). My aim is to determine the cellular distribution and functional properties of PMLD-associated Cx47 mutants (I46M, G149S, G236R, G236S, M286T, T398I). All mutants were detected at the cell-cell interface. These mutants, except G149S and T398I, showed no electrical coupling in …

Post-Transcriptional Regulation Of Telomerase Reverse Transcriptase (Tert) In Human Embryonic Stem Cells Cultured Under Varying Oxygen Microenvironments, Lida Radan

Electronic Thesis and Dissertation Repository

Recent evidence points to extra-telomeric roles of telomerase in regulating stem cell function. In this study, human embryonic stem cells (hESCs) were cultured in 20% or 2% oxygen for up to 5 days and evaluated for telomerase reverse transcriptase (TERT) expression and telomerase activity. Results showed increased cell survival and maintenance of the undifferentiated state with elevated levels of nuclear TERT in 2% oxygen cultured hESCs despite no significant difference in telomerase activity. Pharmacological inhibition of TERT caused spontaneous differentiation while inhibition of the telomerase RNA component (TERC) did not. RT-PCR analysis revealed variations in transcript levels of full-length and …

Human Cerebrovascular Endothelial Cell Responses In Severe Sepsis, Christopher J. Blom

Electronic Thesis and Dissertation Repository

Sepsis-associated encephalopathy (SAE) is an independent predictor of mortality in severe sepsis patients. Mechanisms of SAE are poorly characterized. Pro-inflammatory mediators are up-regulated in blood plasma of severe sepsis patients and may lead to activation/dysfunction of cerebrovascular endothelial cells (CMEC) of the blood-brain barrier (BBB) – potentially contributing to brain dysfunction. The objective of the present study was to determine the effects/mechanisms of both human severe sepsis blood plasma (hSSP; 20% v/v) and a mixture of 8 cytokines/chemokines that mimicked physiological concentrations of cytokines/chemokines in hSSP (cytomix; SSCM) on human-derived CMEC (hCMEC/D3) activation/dysfunction

in vitro. hSSP-stimulation up-regulated hCMEC/D3 pro-adhesive …

Membrane Properties Involved In Calcium-Stimulated Microparticle Release From The Plasma Membranes Of S49 Lymphoma Cells, Lauryl Elizabeth Campbell

Theses and Dissertations

The mechanism of microparticle shedding from the plasma membrane of calcium-loaded cells has been investigated in erythrocytes and platelets. Recent studies have revealed the physiological and clinical importance of microparticle release from nucleated cells such as lymphocytes and endothelium. The experiments of this study were designed to address whether simple mechanisms discovered in platelets and erythrocytes also apply to the more complex nucleated cells. Four such mechanisms were addressed: potassium efflux, transbilayer phosphatidylserine migration, cytoskeleton degradation, and membrane lipid order. The rate and amount of microparticle release in the presence of a calcium ionophore, ionomycin, was assayed by light scatter …

Green Tea Extract Protects Against Fibrogenesis Associated With Nonalcoholic Fatty Liver Disease In Diet-Induced Obese Rats, Allyson M. Bower

Master's Theses

No abstract provided.

Kiss1r Induces Human Mammary Epithelial Cell Invasiveness And Promotes Breast Cancer Cell Migration And Invasion Via Iqgap1, Donna Cvetkovic

Electronic Thesis and Dissertation Repository

Kisspeptins (KP), peptide products of the kisspeptin-1 (KISS1) gene are the endogenous ligands for a G protein-coupled receptor (KISS1R). KISS1 acts as a metastasis suppressor in numerous human cancers. However, recent studies have demonstrated that an increase in KISS1 and KISS1R expression in human breast tumors correlates with higher tumor grade and metastatic potential. We have previously shown that KP-10, the most potent KP, stimulates invasion of estrogen receptor (ER)-negative breast cancer cells via transactivation of the epidermal growth factor receptor (EGFR). Here, I report that KP-10 treatment of the ER-negative non-malignant mammary epithelial MCF10A cells, or stable …

Purification And Reconstitution Into Planar Bilayers Of The Human Dopamine Transporter, Yoori Kim

Theses and Dissertations

The human dopamine transporter (hDAT) provides the primary mechanism for dopamine clearance in synapses and thus facilitates the regulation of dopaminergic functions in cognition and reward. It is the molecular target of many centrally-active agents including amphetamines and cocaine. Therefore, an understanding of hDAT function and its modulation by these therapeutic drugs and drugs of abuse can provide insight into the mechanisms of abuse and addiction. In the presented studies, hDAT is tagged with a hexahistidine construct and heterologously expressed in Xenopus laevis oocytes. The plasma membranes are isolated, solubilized, and applied to a Nickel affinity column to obtain purified …

The Role Of Transforming Growth Factor Alpha In Osteoarthritis And Skeletal Development, Shirine E. Usmani

Electronic Thesis and Dissertation Repository

Osteoarthritis (OA) is the most common joint disease and a major cause of physical disability, however no disease modifying treatments are available. To better understand the molecular mechanisms involved, my colleagues previously performed microarray studies on a surgical rodent model of OA. Transforming growth factor alpha (TGFa) was identified as a novel growth factor involved in cartilage degeneration and subsequent experiments revealed that it induced an OA-like phenotype in articular chondrocytes. These findings lead to the overarching hypothesis for my thesis: TGFa promotes OA.

I began by studying TGFa’s interaction with endothelin receptor A (ET(A)R) as this signaling system is …

Diffusion Barriers Of The Lateral Ventricular System, Anitha Saravanakumar

Master's Theses

Adult neurogenesis in mammalian brain has become a well-accepted phenomenon. The neural stem cells in the sub ventricular zone (SVZ) along the lateral wall of the lateral ventricle, the largest germinal center of adult neurogenesis, are maintained by the neural stem cell niche. One prominent feature of the niche is its close proximity to the cerebral spinal fluid (CSF). The role of micromolecules (such as ions, water and gases) present in the CSF and diffusing through the lateral ventricular wall and how the stem cell micro-environment is maintained is poorly understood. The cytoarchitecture of the lateral ventricular wall with a …

Signal Transduction Effects Induced By Erythropoietin In A Hnscc Model System, Shreya Desai

Theses and Dissertations

Head and Neck Squamous Cell Carcinoma (HNSCC) is an epithelial skin cancer of the upper aerodigestive tract, and is the sixth most common malignancy in the U.S. HNSCC patients undergoing chemotherapy commonly develop anemia, a condition in which the body lacks mature red blood cells (RBCs). Erythropoietin (EPO) is a systemically circulating hormone in the body that regulates the production of RBCs and is applied to treat anemia. Recently, several studies implicated shortened life expectancy of cancer patients by EPO administration. It may be due to an unexpected activation of survival and proliferation pathways of cancer cells by EPO because …

Hypoxia-Induced Alterations In Skeletal Muscle Cell Respiration And Resveratrol As A Potential Pharmacological Intervention, Kathleen R. Belgrave

Electronic Thesis and Dissertation Repository

Using the C₂C₁₂ mouse muscle myoblast cell line, I sought to investigate the hypothesis that differentiation under hypoxia impairs muscle mitochondrial respiratory function irreversibly. Resveratrol (RSV) will increase expression of markers of mitochondrial biogenesis and reverse the hypoxia-induced depression of O₂ consumption rates. Hypoxia decreased oxygen consumption rates after five days of differentiation and after two days of normoxic recovery. This coincided with a hypoxia-induced decrease in protein levels of the NDUFB8 subunit of complex I of the electron transport chain and decreases in mRNA levels of mitochondrial biogenesis transcription factors, both of which could contribute …