Medical Physiology Commons^™

Distinct White Matter Changes Associated With Cerebrospinal Fluid Amyloid-Β1-42 And Hypertension, Omar M. Al-Janabi, Christopher A. Brown, Ahmed A. Bahrani, Erin L. Abner, Justin M. Barber, Brian T. Gold, Larry B. Goldstein, Richard R. Murphy, Peter T. Nelson, Nathan F. Johnson, Leslie M. Shaw, Charles D. Smith, John Q. Trojanowski, Donna M. Wilcock, Gregory A. Jicha

Sanders-Brown Center on Aging Faculty Publications

BACKGROUND: Alzheimer's disease (AD) pathology and hypertension (HTN) are risk factors for development of white matter (WM) alterations and might be independently associated with these alterations in older adults.

OBJECTIVE: To evaluate the independent and synergistic effects of HTN and AD pathology on WM alterations.

METHODS: Clinical measures of cerebrovascular disease risk were collected from 62 participants in University of Kentucky Alzheimer's Disease Center studies who also had cerebrospinal fluid (CSF) sampling and MRI brain scans. CSF Aβ_1-42 levels were measured as a marker of AD, and fluid-attenuated inversion recovery imaging and diffusion tensor imaging were obtained to assess …

Causality Analysis And Cell Network Modeling Of Spatial Calcium Signaling Patterns In Liver Lobules., Aalap Verma, Anil Noronha Antony, Babatunde A. Ogunnaike, Jan B. Hoek, Rajanikanth Vadigepalli

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Dynamics as well as localization of Ca2+ transients plays a vital role in liver function under homeostatic conditions, repair, and disease. In response to circulating hormonal stimuli, hepatocytes exhibit intracellular Ca2+ responses that propagate through liver lobules in a wave-like fashion. Although intracellular processes that control cell autonomous Ca2+ spiking behavior have been studied extensively, the intra- and inter-cellular signaling factors that regulate lobular scale spatial patterns and wave-like propagation of Ca2+ remain to be determined. To address this need, we acquired images of cytosolic Ca2+ transients in 1300 hepatocytes situated across several mouse liver lobules over a period of …

Myocyte [Na+]I Dysregulation In Heart Failure And Diabetic Cardiomyopathy, Sanda Despa

Pharmacology and Nutritional Sciences Faculty Publications

By controlling the function of various sarcolemmal and mitochondrial ion transporters, intracellular Na⁺ concentration ([Na⁺]_i) regulates Ca²⁺ cycling, electrical activity, the matching of energy supply and demand, and oxidative stress in cardiac myocytes. Thus, maintenance of myocyte Na⁺ homeostasis is vital for preserving the electrical and contractile activity of the heart. [Na⁺]_i is set by the balance between the passive Na⁺ entry through numerous pathways and the pumping of Na⁺ out of the cell by the Na⁺/K⁺-ATPase. This equilibrium is perturbed in heart failure, …

Propofol Inhibits The Voltage-Gated Sodium Channel Nachbac At Multiple Sites., Yali Wang, Elaine Yang, Marta M. Wells, Vasyl Bondarenko, Kellie Woll, Vincenzo Carnevale, Daniele Granata, Michael L. Klein, Roderic G. Eckenhoff, William P. Dailey, Manuel Covarrubias, Pei Tang, Yan Xu

Department of Neuroscience Faculty Papers

Voltage-gated sodium (Na_V) channels are important targets of general anesthetics, including the intravenous anesthetic propofol. Electrophysiology studies on the prokaryotic Na_V channel NaChBac have demonstrated that propofol promotes channel activation and accelerates activation-coupled inactivation, but the molecular mechanisms of these effects are unclear. Here, guided by computational docking and molecular dynamics simulations, we predict several propofol-binding sites in NaChBac. We then strategically place small fluorinated probes at these putative binding sites and experimentally quantify the interaction strengths with a fluorinated propofol analogue, 4-fluoropropofol. In vitro and in vivo measurements show that 4-fluoropropofol and propofol have similar effects …

Gender- And Region-Specific Changes In Estrogen Signaling In Aging Rat Brain Mitochondria, Christopher M. Evola, Tanner L. Hudson, Luping Huang, Adrian M. Corbett, Debra A. Mayes

Neuroscience, Cell Biology & Physiology Faculty Publications

Recently epidemiological studies suggest females lose neuroprotection from neurodegenerative diseases as they go through menopause. It has been hypothesized that this neuroprotection is hormone‐dependent. The current study characterized cell signaling molecules downstream of estrogen receptor beta that are known to play a role in memory, PKC, ERK, and connexin‐43, in regions of the brain associated with memory decline in an attempt to elucidate significant changes that occur post‐estrus. Total whole cell lysates were compared to isolated mitochondrial protein because mitochondrial function is known to be altered during aging. As hypothesized, protein concentrations differed depending on age, gender, and brain region. …

High Fat Diet Upregulates Fatty Acid Oxidation And Ketogenesis Via Intervention Of Ppar-Γ., Kunal Sikder, Sanket Kumar Shukla, Neel Patel, Harpreet Singh, Khadija Rafiq

Center for Translational Medicine Faculty Papers

BACKGROUND/AIMS: Systemic hyperlipidemia and intracellular lipid accumulation induced by chronic high fat diet (HFD) leads to enhanced fatty acid oxidation (FAO) and ketogenesis. The present study was aimed to determine whether activation of peroxisome proliferator-activated receptor-γ (PPAR-γ) by surplus free fatty acids (FA) in hyperlipidemic condition, has a positive feedback regulation over FAO and ketogenic enzymes controlling lipotoxicity and cardiac apoptosis.

METHODS: 8 weeks old C57BL/6 wild type (WT) or PPAR-γ-/- mice were challenged with 16 weeks 60% HFD to induce obesity mediated type 2 diabetes mellitus (T2DM) and diabetic cardiomyopathy. Treatment course was followed by echocardiographic measurements, glycemic and …

Artificial Gravity As A Countermeasure To The Cardiovascular Deconditioning Of Spaceflight: Gender Perspectives, Joyce M. Evans, Charles F. Knapp, Nandu Goswami

Biomedical Engineering Faculty Publications

Space flight-induced physiological deconditioning resulting from decreased gravitational input, decreased plasma volume, and disruption of regulatory mechanisms is a significant problem in returning astronauts as well as in normal aging. Here we review effects of a promising countermeasure on cardiovascular systems of healthy men and women undergoing Earth-based models of space-flight. This countermeasure is produced by a centrifuge and called artificial gravity (AG). Numerous studies have determined that AG improves orthostatic tolerance (as assessed by various protocols) of healthy ambulatory men, of men deconditioned by bed rest or by immersion (both wet and dry) and, in one case, following spaceflight. …

Spinal Control Of Locomotion: Individual Neurons, Their Circuits And Functions, Marie-Pascale Côté, Lynda M. Murray, Maria Knikou

Publications and Research

Systematic research on the physiological and anatomical characteristics of spinal cord interneurons along with their functional output has evolved for more than one century. Despite significant progress in our understanding of these networks and their role in generating and modulating movement, it has remained a challenge to elucidate the properties of the locomotor rhythm across species. Neurophysiological experimental evidence indicates similarities in the function of interneurons mediating afferent information regarding muscle stretch and loading, being affected by motor axon collaterals and those mediating presynaptic inhibition in animals and humans when their function is assessed at rest. However, significantly different muscle …

Systematic Pan-Cancer Analysis Of Somatic Allele Frequency., Liam Spurr, Muzi Li, Nawaf Alomran, Qianqian Zhang, Paula Restrepo, Mercedeh Movassagh, Chris Trenkov, Nerissa Tunnessen, Tatiyana Apanasovich, Keith A Crandall, Nathan Edwards, Anelia Horvath

Pharmacology and Physiology Faculty Publications

Imbalanced expression of somatic alleles in cancer can suggest functional and selective features, and can therefore indicate possible driving potential of the underlying genetic variants. To explore the correlation between allele frequency of somatic variants and total gene expression of their harboring gene, we used the unique data set of matched tumor and normal RNA and DNA sequencing data of 5523 distinct single nucleotide variants in 381 individuals across 10 cancer types obtained from The Cancer Genome Atlas (TCGA). We analyzed the allele frequency in the context of the variant and gene functional features and linked it with changes in …

Disruption Of Neonatal Cardiomyocyte Physiology Following Exposure To Bisphenol-A., Manelle Ramadan, Meredith Sherman, Rafael Jaimes, Ashika Chaluvadi, Luther Swift, Nikki Gillum Posnack

Pharmacology and Physiology Faculty Publications

Bisphenol chemicals are commonly used in the manufacturing of polycarbonate plastics, polyvinyl chloride plastics, resins, and thermal printing applications. Humans are inadvertently exposed to bisphenols through contact with consumer products and/or medical devices. Recent reports have shown a link between bisphenol-a (BPA) exposure and adverse cardiovascular outcomes; although these studies have been limited to adult subjects and models. Since cardiac physiology differs significantly between the developing and adult heart, we aimed to assess the impact of BPA exposure on cardiac function, using a neonatal cardiomyocyte model. Neonatal rat ventricular myocytes were monitored to assess cell viability, spontaneous beating rate, beat …

Spinal Cord Trauma: An Overview Of Normal Structure And Function, Primary And Secondary Mechanisms Of Injury, And Emerging Treatment Modalities, Daniel Morin

Senior Honors Theses

The structures of the spinal cord and vertebral column are designed to provide flexibility, while still providing ample protection for the spinal cord deep within. While it does offer remarkable protection against most routine trauma, the spinal cord is still vulnerable to high-force etiologies of trauma and may become damaged as a result. These events are referred to as primary injury. Following the initial injury, the body’s own physiological responses cause a cascade of deleterious effects, known as secondary injury. Secondary injury is a major therapeutic target in mitigating the effects of spinal cord injury (SCI), and much research is …

Effects Of Load Carriage And Surface Inclination On Linear And Non-Linear Postural Variability, Rahul Soangra, Hema Bhatt, Ehsan Rashedi

Physical Therapy Faculty Articles and Research

Understanding of inclined-work-related risk of falls and developing novel practical engineering controls for reducing this risk of falls among hilly working population remains in high demand. Standing on sloped surfaces provides a unique environment for examining the biomechanics and neural control of standing. The present investigation examined the variability of postural signals when standing on inclined surfaces and with load carriages by linear and nonlinear analysis. The purpose of this study was to determine if the sloped surface deteriorated in postural stability among healthy individuals with two distinctive kinds of load carriage methods head versus posterior load carriage. We also …

Osteoarthritis, Cerebrovascular Dysfunction And The Common Denominator Of Inflammation: A Narrative Review, B. K. Al-Khazraji, C. T. Appleton, F. Beier, T. B. Birmingham, J. K. Shoemaker

Physiology and Pharmacology Publications

© 2018 The Author(s) Objective: Population-based cohort studies suggest an association between osteoarthritis (OA) and cerebrovascular disease, yet the mechanisms underlying vascular comorbidities in OA remain unclear. The purpose of this narrative review is to discuss the literature examining inflammation in OA with a focus on physiological mechanisms, and whether overlapping mechanisms exist in cerebrovascular dysfunction. Method: A literature search was conducted in PubMed using combinations of search terms: osteoarthritis, cerebrovascular (disease/dysfunction/risk), cardiovascular (disease/dysfunction/risk), aging/ageing, inflammation, inflammatory mediators, cytokine, c-reactive protein, interleukin, advanced glycation end-products, metabolic syndrome, reactive oxidative species, cognitive impairment, (vascular-related) dementia, small cerebral vessel disease, endothelial function, …

Maternal Nicotine Exposure Leads To Augmented Expression Of The Antioxidant Adipose Tissue Triglyceride Lipase Long-Term In The White Adipose Of Female Rat Offspring., Nicole Barra, Taylor Vanduzer, Alison C. Holloway, Daniel B. Hardy

Physiology and Pharmacology Publications

Globally, approximately 10-25% of women smoke during pregnancy. Since nicotine is highly addictive, women may use nicotine containing products like nicotine replacement therapies for smoking cessation, but the long-term consequences of early life exposure to nicotine remain poorly defined. Our laboratory has previously demonstrated that maternal nicotine exposed (MNE) rat offspring exhibit hypertriglyceridemia due to increased hepatic de novo lipogenesis. Hypertriglyceridemia may also be attributed to impaired white adipose tissue (WAT) lipid storage; however, the effects of MNE on WAT are not completely understood. We hypothesize that nicotine-induced alterations in adipose function (e.g. lipid storage) underlie dyslipidemia in MNE adults. …

Muscle Nicotinic Acetylcholine Receptors May Mediate Trans-Synaptic Signaling At The Mouse Neuromuscular Junction, Xueyong Wang, J. Michael Mcintosh, Mark M. Rich

Neuroscience, Cell Biology & Physiology Faculty Publications

Block of neurotransmitter receptors at the neuromuscular junction (NMJ) has been shown to trigger upregulation of the number of synaptic vesicles released (quantal content, QC), a response termed homeostatic synaptic plasticity. The mechanism underlying this plasticity is not known. Here, we used selective toxins to demonstrate that block of α1-containing nicotinic acetylcholine receptors (nAChRs) at the NMJ of male and female mice triggers the upregulation of QC. Reduction of current flow through nAChRs, induced by drugs with antagonist activity, demonstrated that reduction in synaptic current per se does not trigger upregulation of QC. These data led to the remarkable conclusion …

Trpm7 Current Inactivation: Evidence For Inside-Out Signaling, Tetyana Zhelay, J. Ashot Kozak

Neuroscience, Cell Biology & Physiology Faculty Publications

TRPM7 channels conduct metal cations such as Na+, K+, Ca2+ and Mg2+. In the presence of external Ca2+/Mg2+ TRPM7 has a steeply outwardly rectifying current-voltage (I-V) relation. In the absence of Ca2+/Mg2+ the IV becomes semi-linear. This has been explained by the removal of pore blockade by divalent cations (e.g. Ca2+o/Mg2+o). TRPM7 channels are inhibited by cytoplasmic Mg2+ in a voltage-independent manner, primarily by a reversible reduction in the overall number of conducting channels. Here, we have examined the consequences of external Ca2+ removal and reintroduction on TRPM7 current kinetics. In whole-cell patch clamp with low internal Mg2+, we rapidly …

Novel Antioxidant Properties Of Doxycycline, Dahn L. Clemens, Michael J. Duryee, Cleofes Sarmiento, Andrew Chiou, Jacob D. Mcgowan, Carlos D. Hunter, Sarah L. Schlichte, Jun Tian, Lynell W. Klassen, James R. O'Dell, Geoffrey M. Thiele, Ted R. Mikuls, Matthew C. Zimmerman, Daniel R. Anderson

Journal Articles: Cellular & Integrative Physiology

Doxycycline (DOX), a derivative of tetracycline, is a broad-spectrum antibiotic that exhibits a number of therapeutic activities in addition to its antibacterial properties. For example, DOX has been used in the management of a number of diseases characterized by chronic inflammation. One potential mechanism by which DOX inhibits the progression of these diseases is by reducing oxidative stress, thereby inhibiting subsequent lipid peroxidation and inflammatory responses. Herein, we tested the hypothesis that DOX directly scavenges reactive oxygen species (ROS) and inhibits the formation of redox-mediated malondialdehyde-acetaldehyde (MAA) protein adducts. Using a cell-free system, we demonstrated that DOX scavenged reactive oxygen …

Loss Of The Intellectual Disability And Autism Gene Cc2d1a And Its Homolog Cc2d1b Differentially Affect Spatial Memory, Anxiety, And Hyperactivity, Marta Zamarbide, Adam Oaks, Heather Pond, Julia Adelman, M. Chiara Manzini

Pharmacology and Physiology Faculty Publications

Hundreds of genes are mutated in non-syndromic intellectual disability (ID) and autism spectrum disorder (ASD), with each gene often involved in only a handful of cases. Such heterogeneity can be daunting, but rare recessive loss of function (LOF) mutations can be a good starting point to provide insight into the mechanisms of neurodevelopmental disease. Biallelic LOF mutations in the signaling scaffold CC2D1Acause a rare form of autosomal recessive ID, sometimes associated with ASD and seizures. In parallel, we recently reported that Cc2d1a-deficient mice present with cognitive and social deficits, hyperactivity and anxiety. In Drosophila, loss of the only …

Optimization Of Wavelength Selection For Multispectral Image Acquisition: A Case Study Of Atrial Ablation Lesions, Huda Asfour, S. Guan, Narine Muselimyan, Luther M. Swift, Murray Loew, Narine Sarvazyan

Pharmacology and Physiology Faculty Publications

In vivo autofluorescence hyperspectral imaging of moving objects can be challenging due to motion artifacts and to the limited amount of acquired photons. To address both limitations, we selectively reduced the number of spectral bands while maintaining accurate target identification. Several downsampling approaches were applied to data obtained from the atrial tissue of adult pigs with sites of radiofrequency ablation lesions. Standard image qualifiers such as the mean square error, the peak signal-to-noise ratio, the structural similarity index map, and an accuracy index of lesion component images were used to quantify the effects of spectral binning, an increased spectral distance …

Rhythm: An Open Source Imaging Toolkit For Cardiac Panoramic Optical Mapping, Christopher Gloschat, Kedar Aras, Shubnam Gupta, N. Rokhana Faye, Hanyu Zhang, Matthew W. Kay, Igor R Efimov, +Several Additional Authors

Pharmacology and Physiology Faculty Publications

Fluorescence optical imaging techniques have revolutionized the field of cardiac electrophysiology and advanced our understanding of complex electrical activities such as arrhythmias. However, traditional monocular optical mapping systems, despite having high spatial resolution, are restricted to a two-dimensional (2D) field of view. Consequently, tracking complex three-dimensional (3D) electrical waves such as during ventricular fibrillation is challenging as the waves rapidly move in and out of the field of view. This problem has been solved by panoramic imaging which uses multiple cameras to measure the electrical activity from the entire epicardial surface. However, the diverse engineering skill set and substantial resource …

Group Ii Innate Lymphoid Cells And Microvascular Dysfunction From Pulmonary Titanium Dioxide Nanoparticle Exposure, Alaeddin Bashir Abukabda, Carroll Rolland Mcbride, Thomas Paul Batchelor, William Travis Goldsmith, Elizabeth Compton Bowdridge, Krista Lee Garner, Sherri Friend, Timothy Robert Nurkiewicz

Faculty & Staff Scholarship

Background: The cardiovascular effects of pulmonary exposure to engineered nanomaterials (ENM) are poorly understood, and the reproductive consequences are even less understood. Inflammation remains the most frequently explored mechanism of ENM toxicity. However, the key mediators and steps between lung exposure and uterine health remain to be fully defined. The purpose of this study was to determine the uterine inflammatory and vascular effects of pulmonary exposure to titanium dioxide nanoparticles (nano-TiO2). We hypothesized that pulmonary nano-TiO2 exposure initiates a Th2 inflammatory response mediated by Group II innate lymphoid cells (ILC2), which may be associated with an impairment in uterine microvascular …

Experimental Intravascular Hemolysis Induces Hemodynamic And Pathological Pulmonary Hypertension: Association With Accelerated Purine Metabolism, Victor P. Bilan, Frank Schneider, Enrico M. Novelli, Eric E. Kelley, Sruti Shiva, Mark T. Gladwin, Edwin K. Jackson, Stevan P. Tofovic

Faculty & Staff Scholarship

Pulmonary hypertension (PH) is emerging as a serious complication associated with hemolytic disorders, and plexiform lesions (PXL) have been reported in patients with sickle cell disease (SCD). We hypothesized that repetitive hemolysis per se induces PH and angioproliferative vasculopathy and evaluated a new mechanism for hemolysis-associated PH (HA-PH) that involves the release of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) from erythrocytes. In healthy rats, repetitive admin- istration of hemolyzed autologous blood (HAB) for 10 days produced reversible pulmonary parenchymal injury and vascular remodeling and PH. Moreover, the combination of a single dose of Sugen-5416 (SU, 200mg/kg) and 10-day …

Hcn2 Channels In The Ventral Tegmental Area Regulate Behavioral Responses To Chronic Stress, Peng Zhong, Casey R. Vickstrom, Xiaojie Liu, Ying Hu, Laikang Yu, Han-Gang Yu, Qing-Song Liu

Faculty & Staff Scholarship

Dopamine neurons in the ventral tegmental area (VTA) are powerful regulators of depression-related behavior. Dopamine neuron activity is altered in chronic stress-based models of depression, but the underlying mechanisms remain incompletely understood. Here, we show that mice subject to chronic mild unpredictable stress (CMS) exhibit anxiety- and depressive-like behavior, which was associated with decreased VTA dopamine neuron firing in vivo and ex vivo. Dopamine neuron firing is governed by voltage-gated ion channels, in particular hyperpolarization- activated cyclic nucleotide-gated (HCN) channels. Following CMS, HCN-mediated currents were decreased in nucleus accumbens-projecting VTA dopamine neurons. Furthermore, shRNA-mediated HCN2 knockdown in the VTA was …

S-Nitrosation Of Protein Phosphatase 1 Mediates Alcohol-Induced Ciliary Dysfunction, Michael E. Price, Adam J. Case, Jacqueline A. Pavlik, Jane M. Devasure, Todd A. Wyatt, Matthew C. Zimmerman, Joseph H. Sisson

Journal Articles: Cellular & Integrative Physiology

Alcohol use disorder (AUD) is a strong risk factor for development and mortality of pneumonia. Mucociliary clearance, a key innate defense against pneumonia, is perturbed by alcohol use. Specifically, ciliated airway cells lose the ability to increase ciliary beat frequency (CBF) to β-agonist stimulation after prolonged alcohol exposure. We previously found that alcohol activates protein phosphatase 1 (PP1) through a redox mechanism to cause ciliary dysfunction. Therefore, we hypothesized that PP1 activity is enhanced by alcohol exposure through an S-nitrosothiol-dependent mechanism resulting in desensitization of CBF stimulation. Bronchoalveolar S-nitrosothiol (SNO) content and tracheal PP1 activity was increased in wild-type (WT) …

Sympatho-Excitatory Response To Pulmonary Chemosensitive Spinal Afferent Activation In Anesthetized, Vagotomized Rats, Julia A. Shanks, Zhiqiu Xia, Steven J. Lisco, George J. Rozanski, Harold D. Schultz, Irving H. Zucker, Han-Jun Wang

Journal Articles: Cellular & Integrative Physiology

The sensory innervation of the lung is well known to be innervated by nerve fibers of both vagal and sympathetic origin. Although the vagal afferent innervation of the lung has been well characterized, less is known about physiological effects mediated by spinal sympathetic afferent fibers. We hypothesized that activation of sympathetic spinal afferent nerve fibers of the lung would result in an excitatory pressor reflex, similar to that previously characterized in the heart. In this study, we evaluated changes in renal sympathetic nerve activity (RSNA) and hemodynamics in response to activation of TRPV1-sensitive pulmonary spinal sensory fibers by agonist application …

Direct Conversion Of Mouse Astrocytes Into Neural Progenitor Cells And Specific Lineages Of Neurons, Kangmu Ma, Xiaobei Deng, Xiaohuan Xia, Zhaohuan Fan, Xinrui Qi, Yongxiang Wang, Yuju Li, Yizhao Ma, Qiang Chen, Hui Peng, Jianqing Ding, Chunhong Li, Yunlong Huang, Changhai Tian, Jialin C. Zheng

Journal Articles: Cellular & Integrative Physiology

Background: Cell replacement therapy has been envisioned as a promising treatment for neurodegenerative diseases. Due to the ethical concerns of ESCs-derived neural progenitor cells (NPCs) and tumorigenic potential of iPSCs, reprogramming of somatic cells directly into multipotent NPCs has emerged as a preferred approach for cell transplantation.

Methods: Mouse astrocytes were reprogrammed into NPCs by the overexpression of transcription factors (TFs) Foxg1, Sox2, and Brn2. The generation of subtypes of neurons was directed by the force expression of cell-type specific TFs Lhx8 or Foxa2/Lmx1a.

Results: Astrocyte-derived induced NPCs (AiNPCs) share high similarities, including the expression of NPC-specific genes, DNA methylation …