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Medical Physiology Commons™

Open Access. Powered by Scholars. Published by Universities.®

2005

Articles 1 - 8 of 8

Full-Text Articles in Medical Physiology

Charge Screening By Internal Ph And Polyvalent Cations As A Mechanism For Activation, Inhibition, And Rundown Of Trpm7/Mic Channels, J. Ashot Kozak, Masayuki Matsushita, Angus C. Nairn, Michael D. Cahalan Nov 2005

Charge Screening By Internal Ph And Polyvalent Cations As A Mechanism For Activation, Inhibition, And Rundown Of Trpm7/Mic Channels, J. Ashot Kozak, Masayuki Matsushita, Angus C. Nairn, Michael D. Cahalan

Neuroscience, Cell Biology & Physiology Faculty Publications

The Mg2+-inhibited cation (MIC) current, believed to represent activity of TRPM7 channels, is found in lymphocytes and mast cells, cardiac and smooth muscle, and several other eukaryotic cell types. MIC current is activated during whole-cell dialysis with divalent-free internal solutions. Millimolar concentrations of intracellular Mg2+ (or other divalent metal cations) inhibit the channels in a voltage-independent manner. The nature of divalent inhibition and the mechanism of channel activation in an intact cell remain unknown. We show that the polyamines (spermine, spermidine, and putrescine) inhibit the MIC current, also in a voltage-independent manner, with a potency that parallels …

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A Drosophila Deg/Enac Channel Subunit Is Required For Male Response To Female Pheromones, Heping Lin, Kevin J. Mann, Elena Starostina, Ronald D. Kinser, Claudio W. Pikielny Sep 2005

A Drosophila Deg/Enac Channel Subunit Is Required For Male Response To Female Pheromones, Heping Lin, Kevin J. Mann, Elena Starostina, Ronald D. Kinser, Claudio W. Pikielny

Dartmouth Scholarship

Odorants and pheromones as well as sweet- and bitter-tasting small molecules are perceived through activation of G protein-coupled chemosensory receptors. In contrast, gustatory detection of salty and sour tastes may involve direct gating of sodium channels of the DEG/ENaC family by sodium and hydrogen ions, respectively. We have found that ppk25, a Drosophila melanogaster gene encoding a DEG/ENaC channel subunit, is expressed at highest levels in the male appendages responsible for gustatory and olfactory detection of female pheromones: the legs, wings, and antennae. Mutations in the ppk25 gene reduce or even abolish male courtship response to females in the dark, …

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Endothelial Nitric Oxide Synthase Is Critical For Ischemic Remodeling, Mural Cell Recruitment, And Blood Flow Reserve, Jun Yu, Ebu D. Demuinck, Zhenwu Zhuang, Mary Drinane Aug 2005

Endothelial Nitric Oxide Synthase Is Critical For Ischemic Remodeling, Mural Cell Recruitment, And Blood Flow Reserve, Jun Yu, Ebu D. Demuinck, Zhenwu Zhuang, Mary Drinane

Dartmouth Scholarship

The genetic loss of endothelial-derived nitric oxide synthase (eNOS) in mice impairs vascular endothelial growth factor (VEGF) and ischemia-initiated blood flow recovery resulting in critical limb ischemia. This result may occur through impaired arteriogenesis, angiogenesis, or mobilization of stem and progenitor cells. Here, we show that after ischemic challenge, eNOS knockout mice [eNOS (-/-)] have defects in arteriogenesis and functional blood flow reserve after muscle stimulation and pericyte recruitment, but no impairment in endothelial progenitor cell recruitment. More importantly, the defects in blood flow recovery, clinical manifestations of ischemia, ischemic reserve capacity, and pericyte recruitment into the growing neovasculature can …

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Resting Potential–Dependent Regulation Of The Voltage Sensitivity Of Sodium Channel Gating In Rat Skeletal Muscle In Vivo, Gregory N. Filatov, Martin J. Pinter, Mark M. Rich Aug 2005

Resting Potential–Dependent Regulation Of The Voltage Sensitivity Of Sodium Channel Gating In Rat Skeletal Muscle In Vivo, Gregory N. Filatov, Martin J. Pinter, Mark M. Rich

Neuroscience, Cell Biology & Physiology Faculty Publications

Normal muscle has a resting potential of −85 mV, but in a number of situations there is depolarization of the resting potential that alters excitability. To better understand the effect of resting potential on muscle excitability we attempted to accurately simulate excitability at both normal and depolarized resting potentials. To accurately simulate excitability we found that it was necessary to include a resting potential–dependent shift in the voltage dependence of sodium channel activation and fast inactivation. We recorded sodium currents from muscle fibers in vivo and found that prolonged changes in holding potential cause shifts in the voltage dependence of …

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The Effects Of An Analgesic (Biofreeze®) On The Motoneuron Pool Excitability Of The Soleus Muscle, Desiree R. Barth Aug 2005

The Effects Of An Analgesic (Biofreeze®) On The Motoneuron Pool Excitability Of The Soleus Muscle, Desiree R. Barth

All-Inclusive List of Electronic Theses and Dissertations

Objective: The purpose of this study was to determine the effects on the Hoffman reflex and motor response with an analgesic (Biofreeze®). Design: The study was a 2X6 design. The independent variables in this study were treatment and time. The dependent variables were the H-reflex (volts) and the M response (volts). Treatment was randomly assigned to control for the effects of order. Setting: This study took place in the Exercise Physiology Laboratory located in the Health and Human Performance Building at Indiana State University. Subjects: 14 volunteers who were physically active and had no known neurological problems. Measurements: Skin and …

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Stim1, An Essential And Conserved Component Of Store-Operated Ca2+ Channel Function, Jack Roos, Paul J. Digregorio, Andriy V. Yeromin, Kari Ohlsen, Maria I. Lioudyno, Shenyuan L. Zhang, Olga Safrina, J. Ashot Kozak, Steven L. Wagner, Michael D. Cahalan, Gönül Veliçelebi, Kenneth A. Stauderman May 2005

Stim1, An Essential And Conserved Component Of Store-Operated Ca2+ Channel Function, Jack Roos, Paul J. Digregorio, Andriy V. Yeromin, Kari Ohlsen, Maria I. Lioudyno, Shenyuan L. Zhang, Olga Safrina, J. Ashot Kozak, Steven L. Wagner, Michael D. Cahalan, Gönül Veliçelebi, Kenneth A. Stauderman

Neuroscience, Cell Biology & Physiology Faculty Publications

Store-operated Ca2+ (SOC) channels regulate many cellular processes, but the underlying molecular components are not well defined. Using an RNA interference (RNAi)-based screen to identify genes that alter thapsigargin (TG)-dependent Ca2+ entry, we discovered a required and conserved role of Stim in SOC influx. RNAi-mediated knockdown of Stim in Drosophila S2 cells significantly reduced TG-dependent Ca2+ entry. Patch-clamp recording revealed nearly complete suppression of the Drosophila Ca2+ release-activated Ca2+(CRAC) current that has biophysical characteristics similar to CRAC current in human T cells. Similarly, knockdown of the human homologue STIM1 significantly reduced CRAC channel activity …

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A Developmental Switch In The Response Of Drg Neurons To Ets Transcription Factor Signaling, Simon Hippenmeyer, Eline Vrieseling, Markus Sigrist, Thomas Portmann, Celia Laengle, David R. Ladle, Silvia Arber May 2005

A Developmental Switch In The Response Of Drg Neurons To Ets Transcription Factor Signaling, Simon Hippenmeyer, Eline Vrieseling, Markus Sigrist, Thomas Portmann, Celia Laengle, David R. Ladle, Silvia Arber

Neuroscience, Cell Biology & Physiology Faculty Publications

Two ETS transcription factors of the Pea3 subfamily are induced in subpopulations of dorsal root ganglion (DRG) sensory and spinal motor neurons by target-derived factors. Their expression controls late aspects of neuronal differentiation such as target invasion and branching. Here, we show that the late onset of ETS gene expression is an essential requirement for normal sensory neuron differentiation. We provide genetic evidence in the mouse that precocious ETS expression in DRG sensory neurons perturbs axonal projections, the acquisition of terminal differentiation markers, and their dependence on neurotrophic support. Together, our findings indicate that DRG sensory neurons exhibit a temporal …

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Renal Ischemia And Reperfusion Activates The Eif2 Alpha Kinase Perk, Heather L. Montie, Foaz Kayali, Adam J. Haezebrouck, Noreen F. Rossi, Donald J. Degracia Jan 2005

Renal Ischemia And Reperfusion Activates The Eif2 Alpha Kinase Perk, Heather L. Montie, Foaz Kayali, Adam J. Haezebrouck, Noreen F. Rossi, Donald J. Degracia

PCOM Scholarly Works

Inhibition of protein synthesis occurs in the post-ischemic reperfused kidney but the molecular mechanism of renal translation arrest is unknown. Several pathways have been identified whereby cell stress inhibits translation initiation via phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF2a, phospho-form eIF2a(P)]. Here, we report a 20-fold increase in eIF2a(P) in kidney homogenates following 10 min of cardiac arrest-induced ischemia and 10 min reperfusion. Using immunohistochemistry, we observed eIF2a(P) in tubular epithelial cells in both cortex and medulla, where the greatest eIF2a(P) staining was found in epithelial cells of the so-called watershed area at the corticomedullary junction. …

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