Medical Physiology Commons^™

Swimming Against The Tide: Investigations Of The C-Bouton Synapse, Adam S. Deardorff, Shannon H. Romer, Patrick M. Sonner, Robert E. W. Fyffe

Neuroscience, Cell Biology & Physiology Faculty Publications

C-boutons are important cholinergic modulatory loci for state-dependent alterations in motoneuron firing rate. m2 receptors are concentrated postsynaptic to C-boutons, and m2 receptor activation increases motoneuron excitability by reducing the action potential afterhyperpolarization. Here, using an intensive review of the current literature as well as data from our laboratory, we illustrate that C-bouton postsynaptic sites comprise a unique structural/functional domain containing appropriate cellular machinery (a “signaling ensemble”) for cholinergic regulation of outward K⁺ currents. Moreover, synaptic reorganization at these critical sites has been observed in a variety of pathologic states. Yet despite recent advances, there are still great challenges …

Role Of Astrocyte Network In Edema After Juvenile Traumatic Brain Injury, Andrew Minoru Fukuda

Loma Linda University Electronic Theses, Dissertations & Projects

Juvenile traumatic brain injury (jTBI) is the leading cause of death and disability in young children and adolescents. Despite its lasting detrimental effects on the developing brain, no pharmacological treatment exists. One of the pathological hallmarks of jTBI is edema. Astrocytes play a key role in the edema process, and have been hypothesized that numerous astrocyte networks allow communication and propagation of edema and secondary injury spread. Two key astrocyte proteins are hypothesized to have a central role in the edema process: Aquaporin 4 (AQP4) and Connexin 43 (Cx43). AQP4 is expressed extensively in astrocyte endfeet, which surrounds the blood …

Cc2d1a Regulates Human Intellectual And Social Function As Well As Nf-Κb Signaling Homeostasis., M. Chiara Manzini, Lan Xiong, Ranad Shaheen, Dimira E Tambunan, Stefania Di Costanzo, Vanessa Mitisalis, +15 Additional Authors

Pharmacology and Physiology Faculty Publications

Autism spectrum disorder (ASD) and intellectual disability (ID) are often comorbid, but the extent to which they share common genetic causes remains controversial. Here, we present two autosomal-recessive "founder" mutations in the CC2D1A gene causing fully penetrant cognitive phenotypes, including mild-to-severe ID, ASD, as well as seizures, suggesting shared developmental mechanisms. CC2D1A regulates multiple intracellular signaling pathways, and we found its strongest effect to be on the transcription factor nuclear factor κB (NF-κB). Cc2d1a gain and loss of function both increase activation of NF-κB, revealing a critical role of Cc2d1a in homeostatic control of intracellular signaling. Cc2d1a knockdown in neurons …

Effects Of Various Partial Body Cooling Techniques On Core Temperature During Recovery From Prolonged Cycling-Induced Heat Stress, Afton Danielle Seeley

Masters Theses

The purpose of this study was to investigate the effects of using an ice-vest and a palm cooling device on core and skin temperatures, heart rate, and perceived thermal comfort during a one hour recovery period following exercise in the heat. Ten recreationally active adults cycled for one hour at 50% V0₂ peak on a cycle ergometer while exposed to 36°C 45%relative humidity environmental conditions. Following exercise, each subjectwas exposed to an ice vest, a palm cooling device, or a non cooling control while seated in the environmental chamber for 60 more minutes. No significant differencewas found betweenany of …

Comparison Of Dual- And Tri-Axial Accelerometer Accuracy, Lindsay Powell Toth

Masters Theses

The purpose of this study was to investigate the accuracy of the Omron HJ-720ITC and the Fitbit Zip activity monitors with regard to step count, energy expenditure, and distance traveled measurements. The importance of this research rests in the success rates of pedometer-based physical activity interventions which have been shown to increase physical activity while also enabling weight loss and lowering blood pressure in the adult population. Activity monitors available for retail sale must be found accurate for proper participation in exercise interventions especially low-cost devices as used in this study.

In order to test the accuracy of the Omron …

Survivin As Potential Mediator To Support Autoreactive Cell Survival In Myasthenia Gravis: A Human And Animal Model Study, Linda Louise Kusner, Michael J. Ciesielski, Alexander Marx, Henry J. Kaminski, Robert A. Fenstermaker

Pharmacology and Physiology Faculty Publications

The mechanisms that underlie the development and maintenance of autoimmunity in myasthenia gravis are poorly understood. In this investigation, we evaluate the role of survivin, a member of the inhibitor of apoptosis protein family, in humans and in two animal models. We identified survivin expression in cells with B lymphocyte and plasma cells markers, and in the thymuses of patients with myasthenia gravis. A portion of survivin-expressing cells specifically bound a peptide derived from the alpha subunit of acetylcholine receptor indicating that they recognize the peptide. Thymuses of patients with myasthenia gravis had large numbers of survivin-positive cells with fewer …

Kinase Insert Domain Receptor/Vascular Endothelial Growth Factor Receptor 2 (Kdr) Genetic Variation Is Associated With Ovarian Hyperstimulation Syndrome, Travis J. O'Brien, Arthur F. Harralson, Tuyen Tran, Ian Gindoff, Funda E. Orkunoglu-Suer, David Frankfurter, Paul Gindoff

Pharmacology and Physiology Faculty Publications

Background

The objective of this investigation was to determine if kinase insert domain/vascular endothelial growth factor receptor 2 (KDR/VEGFR2) genetic variation was associated with the development of ovarian hyperstimulation syndrome (OHSS) in patients undergoing controlled ovarian hyperstimulation (COH).

Methods

This was a case-control study of 174 patients who underwent controlled ovarian stimulation. Patient blood samples were genotyped for single nucleotide polymorphisms (SNPs) spanning the KDR locus. OHSS development, clinical outcome variables, SNP and haplotype frequencies were compared between control (n = 155) and OHSS (n = 19) groups.

Results

Patients who developed OHSS had significantly higher response markers (estradiol levels …

Motor Axon Synapses On Renshaw Cells Contain Higher Levels Of Aspartate Than Glutamate, Dannette Shanon Richards, Ronald W. Griffith, Shannon H. Romer, Francisco J. Alvarez

Neuroscience, Cell Biology & Physiology Faculty Publications

Motoneuron synapses on spinal cord interneurons known as Renshaw cells activate nicotinic, AMPA and NMDA receptors consistent with co-release of acetylcholine and excitatory amino acids (EAA). However, whether these synapses express vesicular glutamate transporters (VGLUTs) capable of accumulating glutamate into synaptic vesicles is controversial. An alternative possibility is that these synapses release other EAAs, like aspartate, not dependent on VGLUTs. To clarify the exact EAA concentrated at motor axon synapses we performed a quantitative postembedding colloidal gold immunoelectron analysis for aspartate and glutamate on motor axon synapses (identified by immunoreactivity to the vesicular acetylcholine transporter; VAChT) contacting calbindin-immunoreactive (-IR) Renshaw …

Ponatinib-Induced Adverse Effects: Thrombocytopenia, Pancreatitis And Hepatoxicity-- A Case Report, Saba Hasan, Crystal Fedorkiv, Naba Rahman, Jennifer Andres

Research Day

Abstract: Chronic myeloid leukemia (CML) is a myeloproliferative disease that generates from malignant transformation of pluripotent hematopoietic stem cells. First line treatment for CML is the tyrosine kinase inhibitor (TKI), imatinib. For patients resistant or intolerant to imatinib, other TKIs, dasatinib, nilotinib, and ponatinib, are approved treatments. Patients who are resistant or intolerant to other agents are started on ponatinib as a last line option. Common adverse events of ponatinib are hypertension, dry skin, rash, abdominal pain, constipation, and nausea. More serious adverse effects include cardiovascular effects, fluid retention, pancreatitis, severe myelosuppression, and hepatotoxicity. Treatment for these adverse effects can …

Targeting Therapy To The Neuromuscular Junction: Proof Of Concept, Linda L. Kusner, Namita Satija, Georgiana Cheng, Henry J. Kaminski

Pharmacology and Physiology Faculty Publications

Introduction: The site of pathology in myasthenia gravis (MG) is the neuromuscular junction (NMJ). Our goal was to determine the ability to direct complement inhibition to the NMJ.

Methods: A single-chain antibody directed against the alpha subunit of the acetylcholine receptor was synthesized (scFv-35) and coupled to decay-accelerating factor (DAF, scFv-35-DAF). scFv-35-DAF was tested in a passive model of experimentally acquired MG.

Results: Administration of scFv-35-DAF to mice deficient in intrinsic complement inhibitors produced no weakness despite confirmation of its localization to the NMJ and no evidence of tissue destruction related to complement activation. Rats with experimentally …

Evidence That Bdnf Regulates Heart Rate By A Mechanism Involving Increased Brainstem Parasympathetic Neuron Excitability, Ruqian Wan, Letitia A. Weigand, Ryan Bateman, Kathleen Griffioen, David Mendelowitz, Mark P. Mattson

Pharmacology and Physiology Faculty Publications

Autonomic control of heart rate is mediated by cardioinhibitory parasympathetic cholinergic neurons located in the brainstem and stimulatory sympathetic noradrenergic neurons. During embryonic development the survival and cholinergic phenotype of brainstem autonomic neurons is promoted by brain-derived neurotrophic factor (BDNF). We now provide evidence that BDNF regulates heart rate by a mechanism involving increased brainstem cardioinhibitory parasympathetic activity. Mice with a BDNF haploinsufficiency exhibit elevated resting heart rate, and infusion of BDNF intracerebroventricularly reduces heart rate in both wild-type and BDNF+/− mice. The atropine-induced elevation of heart rate is diminished in BDNF+/− mice and is restored by BDNF infusion, whereas …

Cyclic Nucleotide-Dependent Phosphorylation Regulates Bk-Ca Channel Activity In Human Coronary Artery Smooth Muscle Cells, Raeonda Williams

PCOM Biomedical Studies Student Scholarship

Cardiovascular diseases (CVD) can induce dysfunction in organ systems by attenuating normal blood flow. Gonadal steroids are vasoactive hormones, but their role in contributing to cardiovascular function remains controversial. We have demonstrated that gonadal steroids can relax coronary arteries by opening the large-conductance, calcium- and voltage-activated potassium (BKca) channel in smooth muscle cells by increasing cyclic nucleotide levels; however, the signaling pathways involved remain to be elucidated. The purpose of this study was to identify how phosphorylation (via cAMP- and cGMP-dependent protein kinases) I dephosphorylation (via phosphoprotein phosphatase 2A, PP2A) regulates BKca channel activity in human coronary artery smooth muscle …

Life History Tradeoffs And The Costs Of Reproduction In Arizona Bark Scorpions (Centruroides Sculpturatus), Michael Marie Webber

UNLV Theses, Dissertations, Professional Papers, and Capstones

Tradeoffs in life history evolution result from conflicts in the time and energy that can be simultaneously invested in activities such as growth, reproduction, and survival. Reproduction is an energetically costly activity for organisms, and is known to elicit alterations in the daily activity patterns of individuals. I investigated reproductive tradeoffs in the Arizona Bark Scorpion,Centruroides sculpturatus. To better understand the nature of tradeoffs in this species, I examined the influence of reproductive state on the predatory efficiency and thermal preference of reproductive females. Further, I examined the influence of reproductive activities (i.e. gestation) on the ability of reproductive females …

The Grass Shrimp, Palaemonetes, Pugio: Hypoxic Influences On Embryonic Development, Christensen C. Javier

UNLV Theses, Dissertations, Professional Papers, and Capstones

Grass shrimp,Palaemonetes pugio, can survive in brackish waters and estuarine ecosystems despite the frequent oscillations and fluctuations in salinity, temperature and oxygen. AdultP. pugiohave the ability to osmoregulate (Romney and Reiber 2011), change cardiac parameters to tolerate temperatures (not yet published, Mika and Reiber) and oxyregulate (Guadagnoli and Reiber 2013). Manipulation of cardiac parameters allows for these methods of regulation. However, cardiac contraction and internal convection of oxygen do not occur until later stages of embryonic development. Studies focused on these morphological and physiological advantages may provide further understanding of the regulatory mechanisms within grass shrimp embryos, larvae and adults. …

Extracellular Ubiquitin: Role In Cardiac Myocyte Apoptosis And Myocardial Remodeling, Christopher Ray Daniels

Electronic Theses and Dissertations

Activation of sympathetic nervous system is a key component of myocardial remodeling that generally occurs following ischemia/reperfusion (I/R) injury and myocardial infarction. It induces cardiac myocyte apoptosis and myocardial fibrosis, leading to myocardial dysfunction. Intracellular ubiquitin (UB) regulates protein turnover by the UB-proteosome pathway. The biological functions of extracellular UB in the heart remain largely unexplored. Previously, our lab has shown that β-adrenergic receptor (β-AR) stimulation increases extracellular UB levels, and extracellular UB inhibits β-AR-stimulated apoptosis in adult rat ventricular myocytes (ARVMs). This study explores the role of extracellular UB in myocyte apoptosis, fibroblast phenotype and function, and myocardial remodeling …

Novel Therapeutic Approaches For Ischemic Heart And Brain Injury: Modulation Of Toll-Like Receptor-Mediated Signaling Pathways And Pi3k/Akt Signaling, Chen Lu

Electronic Theses and Dissertations

Innate immune and inflammatory responses contribute to myocardial and cerebral ischemia/reperfusion (I/R) injury. Toll-like receptors (TLRs) play a critical role in the induction of innate immune and inflammatory responses via activation of nuclear factor kappa B (NF-κB). We have shown that activation of NF-κB contributes to myocardial and cerebral I/R injury. Indeed, inhibition of TLR4-mediated NF-κB activation significantly decreased myocardial and cerebral I/R injury via activation of PI3K/Akt signaling. PI3K/Akt signaling is an important pathway in regulating cellular survival and inflammatory responses. Therefore, an important question is how to differentially modulate PI3K/Akt signaling and TLR/NF-κB-mediated signaling pathway during I/R injury? …

9-Phenanthrol And Flufenamic Acid Inhibit Calcium Oscillations In Hl-1 Mouse Cardiomyocytes, Rees A. Burt

Undergraduate Honors Theses

Electrical potentials exist across the membranes of nearly every cell type in the body. In addition, excitable cells, such as neurons, myocytes and even some endocrine cells elicit electrochemical fluctuations, action potentials (AP), in the cell membrane to initiate cell-to-cell communication or intracellular processes. The basis for the electrical potential is rooted within an array of complex interactions between monovalent ions and their associated membrane channels and transporters that regulate the flux of these charged species across the hydrophobic bilayer. Here, an expansion of our recently published work [1] will serve to explore the modern concepts regarding the …

Bisphenol A Exposure And Cardiac Electrical Conduction In Excised Rat Hearts, Nikki G. Posnack, Rafael Jaimes Iii, Huda Asfour, Luther Swift, Anastasia M. Wengrowski, Narine Sarvazyan, Matthew Kay

Pharmacology and Physiology Faculty Publications

BACKGROUND:

Bisphenol A (BPA) is used to produce polycarbonate plastics and epoxy resins that are widely used in everyday products, such as food and beverage containers, toys and medical devices. Human biomonitoring studies have suggested that a large proportion of the population may be exposed to BPA. Recent epidemiological studies have reported correlations between increased BPA urinary concentrations and cardiovascular disease; yet the direct effects of BPA on the heart are unknown.

OBJECTIVES:

The goal of our studies was to measure BPA's effect (0.1-100 μM) on cardiac impulse propagation ex vivo, using excised whole hearts from adult rats.

METHODS: …

Adult Spinal Motoneurones Are Not Hyperexcitable In A Mouse Model Of Inherited Amyotrophic Lateral Sclerosis, Nicolas Delestrée, Marin Manuel, Caroline Iglesias, Sherif M. Elbasiouny, C. J. Heckman, Daniel Zytnicki

Neuroscience, Cell Biology & Physiology Faculty Publications

In amyotrophic lateral sclerosis (ALS), an adult onset disease in which there is progressive degeneration of motoneurones, it has been suggested that an intrinsic hyperexcitability of motoneurones (i.e. an increase in their firing rates), contributes to excitotoxicity and to disease onset. Here we show that there is no such intrinsic hyperexcitability in spinal motoneurones. Our studies were carried out in an adult mouse model of ALS with a mutated form of superoxide dismutase 1 around the time of the first muscle fibre denervations. We showed that the recruitment current, the voltage threshold for spiking and the frequency–intensity gain in the …

Substance P Differentially Modulates Firing Rate Of Solitary Complex (Sc) Neurons From Control And Chronic Hypoxia-Adapted Adult Rats, Nicole L. Nichols, Frank L. Powell, Jay B. Dean, Robert W. Putnam

Neuroscience, Cell Biology & Physiology Faculty Publications

NK1 receptors, which bind substance P, are present in the majority of brainstem regions that contain CO₂/H⁺-sensitive neurons that play a role in central chemosensitivity. However, the effect of substance P on the chemosensitive response of neurons from these regions has not been studied. Hypoxia increases substance P release from peripheral afferents that terminate in the caudal nucleus tractus solitarius (NTS). Here we studied the effect of substance P on the chemosensitive responses of solitary complex (SC: NTS and dorsal motor nucleus) neurons from control and chronic hypoxia-adapted (CHx) adult rats. We simultaneously measured intracellular pH …