Neuroscience and Neurobiology Commons^™

Sk Channel Clustering In Sod1-G93a Motoneurons, Saihari Shekar Dukkipati

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Amyotrophic lateral sclerosis (ALS) is a devastating neuromuscular disease that currently has no cure and extremely limited treatment options. The specific mechanisms that underlie motoneuron degeneration and death, which are classical features of this disease, are mostly unknown. This thesis tests the hypothesis that small-conductance calcium-activated potassium channels (SK) may be downregulated in ALS motoneurons, as suggested by computational modelling. SK channel expression was measured in spinal alpha-motoneuron cell bodies or somata of wildtype (WT) and mutant (mt) SOD1-G93A mice, a transgenic animal model of ALS. Quantitative immunohistochemical analysis of the developmental expression of SK channel isoforms SK2 and SK3 …

Social Buffering By Unfamiliar Adult Males In Preweaning Guinea Pigs (Cavia Pocellus): The Effects On Hpa Activity And Fos Induction In The Medial Prefrontal Cortex, Withayapon Watanasriyakul

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Social buffering, a phenomenon in which the presence of a social partner can reduce stress responses, is often most effective between strongly attached partners. Our laboratory previously found a surprising buffering effect of the hypothalamic-pituitary-adrenal (HPA) response in preweaning guinea pigs by unfamiliar adult males. It was hypothesized that this HPA-buffering effect was driven by social interactions between the two partners and may involve an activation of the prelimbic cortex. Therefore, the current study examined these potential associations. To limit social interactions, the adult male was anesthetized in one condition compared to another condition where the adult male remained conscious. …

The Use Of Doublecortin To Quantify The Effects Of Pharmacological Treatment On Neurogenesis And Functional Recovery After Stroke, Amber Lee Hensley

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Ischemic strokes account for 87% of all strokes and can have debilitating effects on language, sensory, and motor skills. Currently, tPA is the only medication approved by the FDA for the treatment of ischemic stroke, but the window of time to administer the drug is very small. In this thesis, we investigate the use of a simvastatin and fluoxetine drug combination (FS) as a possible treatment for ischemic stroke victims. To analyze the effects of FS on neurogenesis and functional recovery, we utilize the Montoya Staircase and quantify the amount of neurogenesis using doublecortin. Although the results of this study …

Examination Of A Post-Stroke Drug Treatment For Its Effect On Blood Brain Barrier Permeability, And Gene Expression Changes In The Peri-Infarct Region, Ankita Anil Patel

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In this current study, we have investigated this a combination of fluoxetine, simvastatin and ascorbic acid administered daily beginning at 20-26 hours after stroke induction. We hope to understand therapeutic abilities by studying its effectiveness on the blood brain barrier permeability and gene expression changes of the microglial subtypes involved in neuro-inflammation and neurogenesis factors in the peri-infarct region. Our results indicate that S-enantiomer of fluoxetine may be more beneficial compared to the R-enantiomer. The S-enantiomer was effective in tightening the blood brain barrier in contrast to the R-enantiomer, in which the latter showed a greater Evans Blue dye permeability …

Correlations Between Sensory Encoding And Central Morphology Of Muscle Proprioceptors In The Rat, Hanna Marie Gabriel

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Until now, observations regarding the central morphology and organization of Ia, group II and Ib Golgi tendon organ afferents have been confined to the cat model. As the use of rodents in the study of the development and organization of segmental spinal cord circuitry increases, a complete account of the peripheral encoding and central connectivity of rodent muscle proprioceptors is necessary. The data presented in this study establish the central morphology and spatial distribution of 12 (4 of each class) functionally phenotyped muscle proprioceptor afferents in the rat by intracellular labeling with Neurobiotin. Each afferent type showed a characteristic central …

Effect Of Somatostatin On Voltage-Gated Calcium Influx In Isolated Neonatal Rat Carotid Body Type I Cells, Eric J. Dunn

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Somatostatin (SST) is a neuropeptide hormone that regulates the release of secondary hormones. Evidence suggests SST plays a neuromodulatory role due to its distribution throughout the central nervous system. Interestingly, SST has been suggested to affect the carotid body, the small peripheral chemoreceptors that regulate breathing. It has been shown that the peripheral chemoreflex sensitivity to CO2 and hypoxia is reduced by SST in humans (Pedersen et al., 1999; Pandit et al., 2014). SST has also been found to inhibit whole cell Ca2+ currents recorded from adult rat carotid body type I cells (e Silva & Lewis, 1995), but the …

Sensorimotor Analysis Of Oxaliplatin Treated Rats, Krystyna Blanka Wieczerzak

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There is currently no direct evidence that chemotherapy induced peripheral neuropathy (CIPN) necessarily explains the sensorimotor deficits seen in 90% patients treated with oxaliplatin (OX). Some patients develop sensory symptoms without CIPN. Our laboratory reported abnormal signaling from IA afferents in OX treated rats with no evidence of neuropathy. We hypothesized that in the absence of CIPN, the behavioral disability is associated with impaired sensory encoding in OX treated rats. The purpose of this study was to investigate the sensorimotor abilities of OX treated rats. The battery of behavioral tests was designed to address proprioception and sensorimotor integration. In the …

Metabolic Characterization Of Mpnst Cell Lines, Christopher A. Waker

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Malignant transformation is the process by which cells develop cancer properties. While many causes for malignant transformation are known (i.e. common genetic mutations and/or exposure to toxins or viruses), the basic requirements that allow a cell to stay alive with altered nutrient and energy requirements are just now being studied. In some tumor types malignant cells undergo changes that result in metabolic differences compared to normal cells. These can include defects in mitophagy resulting in an accumulation of dysfunctional mitochondria and/or a metabolic switch resulting in increased glycolysis, termed the Warburg effect. Increased tumor growth and metastasis have also been …

The Camkkβ Inhibitor Sto-609 Causes Artefacts In Ca2+ Imaging And Selectively Inhibits Bkca In Mouse Carotid Body Type I Cells, Jennifer G. Jurcsisn

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It has previously been reported that AMP-activated protein kinase (AMPK) may be critical for hypoxic chemotransduction in carotid body type I cells (Wyatt et al, 2007). This study sought to determine the importance of the regulatory upstream kinase of AMPK, CamKKβ, in the acute response to hypoxia in isolated mouse type I cells.

Initial studies indicated several previously unreported artefacts associated with using the CamKKβ inhibitor STO-609 and calcium imaging techniques. Strong STO-609 autofluorescence meant that Fura-2 could not be used and X-Rhod-1 imaging revealed that STO-609 quenched fluorescence even in the absence of intracellular Ca2+. The whole-cell configuration of …

Investigating Anatomical And Molecular Aspects Of Proprioceptive Sensory Neuron Diversity Using A Transgenic Mouse Model, Martha Jean Sonner

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Muscle spindles (MS) and Golgi tendon organs (GTOs) are encapsulated, stretch-activated sensory receptors housed within skeletal muscles, yet their functional contributions to proprioceptive monitoring of limb movements are quite different. For example, MS are responsible for detecting stretch of muscle fibers, and GTOs provide feedback regarding muscle tension during contraction. Peripheral axons extending from proprioceptive sensory neurons (PSNs) in the dorsal root ganglia supply MS and GTOs. MS are innervated by Group Ia and II sensory fiber endings, while GTOs are innervated by a single Group Ib sensory fiber. The developmental processes guiding axons from PSNs to their targets and …

Effects Of Transcranial Direct Current Stimulation On Expression Of Immediate Early Genes (Ieg's), Jessica Wagner

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Transcranial direct current stimulation (tDCS) has been utilized in human studies to modulate a multitude of psychological, cognitive, and psychiatric disorders. There have been positive behavioral results in human subjects but our knowledge of biological processes occurring during stimulation to elicit behavioral outcomes is limited. Our study utilizes a rodent tDCS (R-tDCS) model in which Sprague Dawley rats receive tDCS in order to examine whether tDCS affects neuronal activation. We examined two immediate early genes (IEG's), cFos and zif268, in order to discern if tDCS affects neuronal activation. Our findings indicate that tDCS does affect neuronal activation by means of …

Hcn1 Immunoreactivity Of Α-Motoneurons Following Peripheral Nerve Injury, Saif Ahmed

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Peripheral axotomy causes significant alterations in intrinsic motoneuron activity and excitability. Despite successful reinnervation of peripheral targets after injury, the recovery of motor function is incomplete. Following axotomy in the adult cat, there is an increase in the afterhyperpolarization (AHP) of the action potential in specific motoneuron types. AHP duration can be inversely correlated with the amount of Ih or sag current and further shaped through SK (Small conductance calcium-activated potassium) channel currents (Gustafsson and Pinter, 1985; Kuno, Miyata, and Muñoz-Martinez, 1974a). Hyperpolarizing-cyclic nucleotide gated (HCN) channels underlie sag currents and are critical to neuronal function by their unique property …

Comparing Two Different Statins In A Delayed Pharmacological Treatment For Ischemic Stroke, Kailyn M. Hagerty

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Stroke is one of the leading causes of death and the top cause of long term disability. Currently there exists no standardized treatment of care for ischemic stroke patients during the days following stroke other than giving aspirin. A drug combination containing fluoxetine, one of two statins, and ascorbic acid was used to try and improve motor function following strokes in rats. Endothelin induced stroke survival surgery was performed on the right cortex of Long Evans and Sprague Dawley rats. Functional tests were completed pre- and post-surgery and immunohistochemistry was carried out to analyze infarct volume, angiogenesis, and the glial …

Quantitative Analysis Of Glycinergic Neurons Including Ia Inhibitory Interneurons In The Ventral Spinal Cord Using A Bac-Glyt2-Egfp Transgenic Mouse Model, Palak Rajeshkumar Painter

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We are interested in understanding the development of reciprocal inhibition, an important sensory-motor circuit that prevents co-contraction of antagonist muscles during locomotion. This effect is mediated by a subset of glycinergic neurons termed Ia inhibitory interneurons (IaINs). Transgenic mouse models are useful in helping to identify subsets of neurons in developing animals. In this thesis we first wanted to test the BAC-GlyT2-eGFP mice model by measuring GFP expression overlap in neurons with glycine in late-stage embryos (E17.5) and early postnatal animals (P0/P1). Our results suggest more than 98% of glycinergic neurons at these stages also express GFP in GlyT2-EGFP transgenic …

The Use Of Forelimb Asymmetry Functional Tests To Determine Motor Recovery With Various Drug Treatments Following Endothelin-Induced Stroke, Kelly Rebecca Leach

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Our laboratory has found increased functional recovery post-stroke with Long Evans rats that received a combination of fluoxetine, simvastatin, and vitamin C. The objectives of this study were to test that treatment and other drug combinations on Sprague Dawley rats, to determine whether Forelimb Asymmetry is a reliable behavioral measure for stroke studies, and to determine the most optimal surgical procedure on Sprague Dawley rats. There were more significant increases in functional recovery observed on the Forelimb Asymmetry than on Montoya Staircase behavioral tests, but there were no significant differences between treatment groups and control. The largest number of rats …

Expressing Human Orai3 In Insect Cells For Pharmacological Studies, Orville R. Bennett

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The Orai3 protein forms a Ca2+ channel with a pharmacological profile distinct from its close relative, the store-operated Ca2+ channel Orai1. Though closely related to Orai1, the function of Orai3 in humans is still unclear. This study attempts to contribute to the body of knowledge by undertaking a pharmacological analysis of Orai3 in insect cells. We describe here the creation of a vector capable of expressing the mammalian Orai3 gene on an insect background. We demonstrate the ability to induce gene expression of Orai3 in these insect cells, and then assess the effectiveness of this system by characterizing the pharmacological …

Environmental Enrichment-Mediated Neuroprotection Against Traumatic Brain Injury:Role Of Brain-Derived Neurotrophic Factor, Kyle Leann Traver

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Each year there are over 1.7 million traumatic brain injuries (TBI) in the United States causing long-term health deficits and significant medical costs. This growing epidemic has led researchers to find methods for treating and preventing these injuries. Environmental Enrichment (EE) is an innovative technique shown to improve cognitive and functional outcomes following a TBI; however, the beneficial effects before injury have not been established. Brain-Derived Neurotrophic Factor (BDNF) has been determined as a neuroprotective biomolecule in TBI. This research examined these two protective components and their roles in TBI. It was hypothesized that BDNF mRNA and protein levels would …

Synaptic Contact Localization In Three Dimensional Space Using A Center Distance Algorithm, Benjamin D. Ausdenmoore

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Spatial distribution of synaptic inputs on the dendritic tree of a neuron can have significant influence on neuronal function. Consequently, accurate anatomical reconstructions of neuron morphology and synaptic localization are critical when modeling and predicting physiological responses of individual neurons. Historically, generation of three-dimensional (3D) neuronal reconstructions together with comprehensive mapping of synaptic inputs has been an extensive task requiring manual identification of putative synaptic contacts directly from tissue samples or digital images. Recent developments in neuronal tracing software applications have improved the speed and accuracy of 3D reconstructions, but localization of synaptic sites through the use of pre- and/or …

The Role Of Nucleotide Signaling In The Regulation Of Icl,Swell In Human 1321n1 Astrocytoma Cells, Ian C. Wenker

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Swollen cells expel osmolytes to decrease volume in a process referred to as Regulatory Volume Decrease, or RVD. The plasma membrane current ICl,swell is ubiquitously expressed in mammalian cells and contributes significantly to RVD. In a variety of cell types, activation of ICl,swell is enhanced by nucleotide signaling. In this study, we used human astrocytoma cells to examine whether nucleotide signaling is necessary or sufficient for ICl,swell activation. Three clones of the 1321N1 human astrocytoma cell line were used for voltage clamp recordings. One clone was transfected with P2Y1 receptors, another with P2Y2 receptors and a third was devoid of …

Clamping Of Intracellular Ph In Neurons From Neonatal Rat Brainstem During Hypercapnia, Vivian C. Nanagas

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In this work, I have made attempts to clamp intracellular pH in the presence of hypercapnic acidosis (HA) in neurons from the locus coeruleus (LC) and nucleus of the solitary tract (NTS) in neonatal rat (ages P3 to P17) brainstem slices. Two approaches were used to minimize hypercapnia-induced ΔpH_i: 1) an increase in intracellular buffering power with a high HEPES concentration using whole cell patching techniques in individual neurons, and 2) a weak acid diffusion technique that relies on an efflux of weak acid to counterbalance HA influx thereby clamping pH_i in multiple neurons at once. pH …

Ultrastructural Analysis Of Excitatory And Inhibitory Synapses Within The Medial Nucleus Of The Trapezoid Body Of Normal Hearing And Congenitally Deaf Mice, Melissa A. Bautista

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The auditory brainstem has been the area of much focus in recent years due to its advantages in circuitry and synaptic connections. The endbulbs and calyces of Held are large, glutamatergic synapses within the AVCN and MNTB, respectively. Because of their large size and accessibility these synapses have offered the ability to study pre- and post-synaptic mechanisms of neurotransmission within the central nervous system. The calyx of Held synapse is the main excitatory input into the MNTB principal cells, containing hundreds of individual synaptic specializations, or release sites. Previous studies have identified physiological and morphological changes at the endbulb of …

Sensitization To Trail-Induced Apoptosis In K-Ras 12 Mutant Pancreatic Cancer Cells By Bitc, Christina Ann Wicker

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Pancreatic adenocarcinoma is an aggressive cancer with a greater than 95% mortality rate and short survival after diagnosis. Chemotherapeutic resistance hinders successful treatment. This resistance is associated with mutations within codon 12 of the K-Ras gene (K-Ras 12), which is present in over 90% of all pancreatic adenocarcinomas. Codon 12 mutations maintain Ras in a constitutively active state leading to continuous cellular proliferation. Our study determined if TRAIL resistance in pancreatic adenocarcinomas with K-Ras 12 mutations could be overcome by first sensitizing the cells with Benzyl isothiocyanate (BITC). BITC is a component of cruciferous vegetable extracts and a cell cycle …

Regulation Of Calcium Entry Pathway In Jurkat T Cells, Petronilla A. Fruasaha

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Calcium release-activated calcium channels (CRAC) control influx of calcium in human T lymphocytes. Hour-long calcium elevations are necessary for efficient gene expression during T cell activation and proliferation. We report here that, the time course for store-operated Ca2+ entry is short-lived (3-4 min) and therefore, cannot account for the prolonged Ca2+ elevations necessary for NFAT translocation into nucleus. Previous findings strongly suggest that T cell activation is accompanied by cytosolic alkalinization. Here, we show that pH changes in Jurkat T cells following activation with mitogenic lectin, phytohemagglutinin (PHA), depends on the length of time of exposure and the concentration (potency) …