Physiological Processes Commons^™

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 …

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 …

Endothelial-Specific Expression Of Caveolin-1 Impairs Microvascular Permeability And Angiogenesis, Philip M. Bauer, Jun Yu, Yan Chen, Reed Hickey, Pascal N. Bernatchez, Robin Looft-Wilson, Yan Huang, Frank Giordano, Radu V. Stan, William C. Sessa

Dartmouth Scholarship

The functions of caveolae and/or caveolins in intact animals are beginning to be explored. Here, by using endothelial cell-specific transgenesis of the caveolin-1 (Cav-1) gene in mice, we show the critical role of Cav-1 in several postnatal vascular paradigms. First, increasing levels of Cav-1 do not increase caveolae number in the endothelium in vivo. Second, despite a lack of quantitative changes in organelle number, endothelial-specific expression of Cav-1 impairs endothelial nitric oxide synthase activation, endothelial barrier function, and angiogenic responses to exogenous VEGF and tissue ischemia. In addition, VEGF-mediated phosphorylation of Akt and its substrate, endothelial nitric oxide synthase, were …

Distinct Properties Of Crac And Mic Channels In Rbl Cells, J. Ashot Kozak, Hubert H. Kerschbaum, Michael D. Cahalan

Neuroscience, Cell Biology & Physiology Faculty Publications

In rat basophilic leukemia (RBL) cells and Jurkat T cells, Ca²⁺ release–activated Ca²⁺ (CRAC) channels open in response to passive Ca²⁺ store depletion. Inwardly rectifying CRAC channels admit monovalent cations when external divalent ions are removed. Removal of internal Mg²⁺ exposes an outwardly rectifying current (Mg²⁺-inhibited cation [MIC]) that also admits monovalent cations when external divalent ions are removed. Here we demonstrate that CRAC and MIC currents are separable by ion selectivity and rectification properties: by kinetics of activation and susceptibility to run-down and by pharmacological sensitivity to external Mg²⁺, spermine, and …

Single Channel Properties And Regulated Expression Of Ca2+ Release-Activated Ca2+ (Crac) Channels In Human T Cells, Alla F. Fomina, Christopher M. Fanger, J. Ashot Kozak, Michael D. Cahalan

Neuroscience, Cell Biology & Physiology Faculty Publications

Although the crucial role of Ca²⁺ influx in lymphocyte activation has been well documented, little is known about the properties or expression levels of Ca²⁺ channels in normal human T lymphocytes. The use of Na⁺ as the permeant ion in divalent-free solution permitted Ca²⁺ release-activated Ca²⁺ (CRAC) channel activation, kinetic properties, and functional expression levels to be investigated with single channel resolution in resting and phytohemagglutinin (PHA)-activated human T cells. Passive Ca²⁺ store depletion resulted in the opening of 41-pS CRAC channels characterized by high open probabilities, voltage-dependent block by extracellular Ca²⁺ in …

Staphylococcal Enterotoxin B Primes Cytokine Secretion And Lytic Activity In Response To Native Bacterial Antigens, K. M. Mason, T. D. Dryden, Nancy J. Bigley, P. S. Fink

Neuroscience, Cell Biology & Physiology Faculty Publications

Superantigens stimulate T-lymphocyte proliferation and cytokine production, but the effects of superantigen exposure on cell function within a complex, highly regulated immune response remain to be determined. In this study, we demonstrate that superantigen exposure significantly alters the murine host response to bacterial antigens in an in vitro coculture system. Two days after exposure to the superantigen staphylococcal enterotoxin B, splenocytes cultured with Streptococcus mutans produced significantly greater amounts of gamma interferon (IFN-gamma) and interleukin-12 than did sham-injected controls. The majority of IFN-gamma production appeared to be CD8(+) T-cell derived since depletion of this cell type dramatically reduced the levels …

Identifying Swelling-Activated Channels From Ion Selectivity Patterns, Dan R. Halm

Neuroscience, Cell Biology & Physiology Faculty Publications

No abstract provided.

Direct Demonstration Of Retroviral Recombination In A Rhesus Monkey, Dawn P. Wooley, Randall A. Smith, Susan Czajak, Ronald C. Desrosiers

Neuroscience, Cell Biology & Physiology Faculty Publications

Recombination may be an important mechanism for increasing variation in retroviral populations. Retroviral recombination has been demonstrated in tissue culture systems by artificially creating doubly infected cells. Evidence for retroviral recombination in vivo is indirect and is based principally on the identification of apparently mosaic human immunodeficiency virus type 1 genomes from phylogenetic analyses of viral sequences. We infected a rhesus monkey with two different molecularly cloned strains of simian immunodeficiency virus. One strain of virus had a deletion in vpx and vpr, and the other strain had a deletion in nef. Each strain on its own induced low virus …

A Recombinant Inwardly Rectifying Potassium Channel Coupled To Gtp-Binding Proteins, Kim W. Chan, M. Noelle Langan, Jin Liang Sui, J. Ashot Kozak, Amanda Pabon, John A. A. Ladias, Diomedes E. Logothetis

Neuroscience, Cell Biology & Physiology Faculty Publications

GTP-binding (G) proteins have been shown to mediate activation of inwardly rectifying potassium (K+) channels in cardiac, neuronal and neuroendocrine cells. Here, we report functional expression of a recombinant inwardly rectifying channel which we call KGP (or hpKir3.4), to signify that it is K+ selective, G-protein-gated and isolated from human pancreas. KGP expression in Xenopus oocytes resulted in sizeable basal (or agonist-independent) currents while coexpression with a G-protein-linked receptor, yielded additional agonist-induced currents. Coexpression of KGP and hGIRK1 (a human brain homolog of GIRK1/Kir3.1) produced much larger basal currents than those observed with KGP or hGIRK1 alone, and upon coexpression …

Effects Of Natural Sequence Variation On Recognition By Monoclonal Antibodies Neutralize Simian Immunodeficiency Virus Infectivity, Weon Sang Choi, Catherine Collignon, Clotilde Thiriart, Dawn P. Wooley, E. J. Scott, Karen A. Kent, Ronald C. Desrosiers

Neuroscience, Cell Biology & Physiology Faculty Publications

The determinants of immune recognition by five monoclonal antibodies (KK5, KK9, KK17, Senv7.1, and Senv101.1) that neutralize simian immunodeficiency virus infectivity were analyzed. These five neutralizing monoclonal antibodies were generated to native SIVmac251 envelope glycoprotein expressed by a vaccinia virus recombinant vector. All five recognize conformational or discontinuous epitopes and require native antigen for optimal recognition. These monoclonal antibodies also recognize SIVmac239 gp120, but they do not recognize gp120 of two natural variants of SIVmac239, 1-12 and 8-22, which evolved during the course of persistent infection in vivo (D.P.W. Burns and R.C. Desrosiers, J. Virol. 65:1843-1854, 1991). Recombinant viruses which …

External Locus Of Control And Negative Life Experiences In Persons With Chronic Fatigue And Immune Dysfunction Syndrome, Pamela Thomas Priebe

Graduate Theses

A review of related literature indicated a person's perception of negative life experiences may be unusually high prior to the onset of an illness. An external locus of control belief system may also be present prior to the onset of an illness. The present study used the Life Experiences Survey measure to compare the perception of life experiences of a group of people with CFIDS and a group of people without CFIDS. The present study also used the Locus of Control Scale to measure the locus of control belief system for the same two groups of people. The results of …

High Rates Of Frameshift Mutations Within Homo-Oligomeric Runs During A Single Cycle Of Retroviral Replication, Dawn P. Wooley, H. M. Temin

Neuroscience, Cell Biology & Physiology Faculty Publications

Homo-oligomeric runs were inserted into a spleen necrosis virus-based retrovirus vector to determine the nature and rate of mutations within runs of 10 to 12 identical nucleotides during a single replication cycle. Clones of helper cells containing integrated copies of retroviral vectors were used to produce virus for infection of target (nonhelper) cells. Proviral sequences from target cell clones were compared with proviral sequences from helper cell clones to study mutations that occurred during a single cycle of replication. In addition to the internal region spanning the homo-oligomeric inserts, a naturally occurring run of 10 T's in the long terminal …

Simian Immunodeficiency Virus Mutants Resistant To Serum Neutralization Arise During Persistent Infection Of Rhesus Monkeys, Dawn P. Wooley, Catherine Collignon, Ronald C. Desrosiers

Neuroscience, Cell Biology & Physiology Faculty Publications

We previously described the pattern of sequence variation in gp120 following persistent infection of rhesus monkeys with the pathogenic simian immunodeficiency virus SIVmac239 molecular clone (D.P.W. Burns and R.C. Desrosiers, J. Virol. 65:1843, 1991). Sequence changes were confined largely to five variable regions (V1 to V5), four of which correspond to human immunodeficiency virus type 1 (HIV-1) gp120 variable regions. Remarkably, 182 of 186 nucleotide substitutions that were documented in these variable regions resulted in amino acid changes. This is an extremely nonrandom pattern, which suggests selective pressure driving amino acid changes in discrete variable domains. In the present study, …

Gelatinase Activity In The Mouse Uterus During Early Pregnancy, Carol A. Brenner, Richard R. Adler, Gary L. Nieder

Neuroscience, Cell Biology & Physiology Faculty Publications

No abstract provided.

Anion Permeation In An Apical Membrane Chloride Channel Of A Secretory Epithelial Cell, Dan R. Halm, Raymond A. Frizzell

Neuroscience, Cell Biology & Physiology Faculty Publications

Single channel currents though apical membrane Cl channels of the secretory epithelial cell line T84 were measured to determine the anionic selectivity and concentration dependence of permeation. The current-voltage relation was rectified with single channel conductance increasing at positive potentials. At 0 mV the single channel conductance was 41 ± 2 pS. Permeability, determined from reversal potentials, was optimal for anions with diameters between 0.4 and 0.5 nm. Anions of larger diameter had low permeability, consistent with a minimum pore diameter of 0.55 nm. Permeability for anions of similar size was largest for those ions with a more symmetrical charge …

Strain-Specific Neutralizing Determinant In The Transmembrane Protein Of Simian Immunodeficiency Virus, Toshiaki Kodama, Dawn P. Wooley, Daniel P. Silva, Fulvia Dimarzo Veronese, Ronald C. Desrosiers

Neuroscience, Cell Biology & Physiology Faculty Publications

Monoclonal antibody SF8/5E11, which recognizes the transmembrane protein (TMP) of simian immunodeficiency virus of macaque monkeys (SIVmac), displayed strict strain specificity. It reacted with cloned and uncloned SIVmac251 but not with cloned SIVmac142 and SIVmac239 on immunoblots. This monoclonal antibody neutralized infection by cloned, cell-free SIVmac251 and inhibited formation of syncytia by cloned SIVmac251-infected cells; these activities were specific to cloned SIVmac251 and did not occur with the other viruses. Site-specific mutagenesis was used to show that TMP amino acids 106 to 110 (Asp-Trp-Asn-Asn-Asp) determined the strain specificity of the monoclonal antibody. This strain-specific neutralizing determinant is located within a …

Selection Of Genetic Variants Of Simian Immunodeficiency Virus In Persistently Infected Rhesus Monkeys, Dawn P. Wooley, Ronald C. Desrosiers

Neuroscience, Cell Biology & Physiology Faculty Publications

Genetic and antigenic variation may be one means by which lentiviruses that cause AIDS avoid elimination by host immune responses. Genetic variation in the envelope gene (env) was studied by comparing the nucleotide sequences of 27 clones obtained from two rhesus monkeys infected with molecularly cloned simian immunodeficiency virus. All 27 clones differed from each other and differed from the input clone in the gp120 (SU) portion of the envelope gene. Nucleotide substitutions were shown to accumulate with time at an average rate of 8.5 per 1,000 per year in SU. Surprisingly, the majority of nucleotide substitutions (81%) resulted in …

Significance Of Premature Stop Codons In Env Of Simian Immunodeficiency Virus, Toshiaki Kodama, Dawn P. Wooley, Yathirajulu M. Naidu, Harry W. Kestler Iii, Muthiah D. Daniel, Yen Li, Ronald C. Desrosiers

Neuroscience, Cell Biology & Physiology Faculty Publications

The location of the translational termination codon for the transmembrane protein (TMP) varies in three infectious molecular clones of simian immunodeficiency virus from macaques (SIV_mac). The SIV_mac251 and SIV_mac142 infectious clones have premature stop signals that differ in location by one codon; transfection of these DNAs into human HUT-78 cells yielded virus with a truncated TMP (28 to 30 kilodaltons [kDa]). The SIV_mac239 infectious clone does not have a premature stop codon in its TMP-coding region. Transfection of HUT-78 cells with this clone initially yielded virus with a full-length TMP (41 kDa). …

Psychophysiological Assessment Of Panic Disorder, Kent A. Koehn

Masters Theses

This study compared physiological and psychological measures between 9 subjects meeting the DSM-III-R criteria for panic disorder (PD) and 9 control subjects to identify psychophysiological differences that might be relevant to the etiology and maintenance of panic attacks. The subjects were assessed through a number of self-report measures and across three laboratory sessions involving five experimental conditions: baseline, role play, relaxation, mental arithmetic, and cold pressor. We measured electrodermal (EDG) and electro-myographic activity (EMG), heart rate (HR), and blood volume pulse (BVP) in terms of absolute values, reactivity, and habituation. Both groups were also assessed in their ability to accurately …

Aldosterone Stimulates K Secretion Across Mammalian Colon Independent Of Na Absorption, Gerhard Rechkemmer, Dan R. Halm

Neuroscience, Cell Biology & Physiology Faculty Publications

K transport across guinea pig (Cavia porcellus) distal colon was measured in vitro using isotopically determined unidirectional fluxes. Aldosterone stimulated electrogenic Na absorption, as measured by amiloride-sensitive short-circuit current (I_sc), and reduced net K absorption from +2.5 ± 0.2 µEq/cm² per hr to +0.8 ± 0.3 µEq/cm² per hr (mean ± SEM). Amiloride addition to the mucosal solution did not enhance net K absorption, as expected if inhibiting active Na absorption would reduce active K secretion as in the distal nephron. The amiloride-insensitive I_sc was -1.0 ± 0.2 µEq/cm² per hr (mean ± SEM) …

Pentylenetetrazol-Induced Seizures In Pigeons And The Effects Of Ethosuximide Thereon, James J. Jakubow

Masters Theses

Previous research has shown that ethosuximide in high enough doses will disrupt operant responding in pigeons. Whether or not these same doses will protect against seizure activity in this species has not been previously tested.

To test this question a system for scoring pentylenetetrazol-induced seizures in pigeons was developed and the effects of ethosuximide on such seizures were evaluated. In Experiment 1 pentylenetetrazol at 15, 27 and 47 mg/kg reliably induced seizures. In Experiment 2 non-behaviorally active and behaviorally active doses of ethosuximide were tested for their seizure controlling effectiveness.

Doses of 20, 40, 80, 160 and 320 mg/kg ethosuximide …

Electrophysiology Of Flounder Intestinal Mucosa. I. Conductance Properties Ofthe Cellular And Paracellular Pathways, Dan R. Halm, Edward J. Krasny Jr., Raymond A. Frizzell

Neuroscience, Cell Biology & Physiology Faculty Publications

We evaluated the conductances for ion flow across the cellular and paracellular pathways of flounder intestine using microelectrode techniques and ion-replacement studies. Apical membrane conductance properties are dominated by the presence of Ba-sensitive K channels. An elevated mucosal solution K concentration, [K]_m, depolarized the apical membrane potential (ψ_a) and, at [K]_m less than 40 mM, the K dependence of ψ_a was abolished by 1-2 mM mucosal Ba. The basolateral membrane displayed Cl conductance behavior, as evidenced by depolarization of the basolateral membrane potential (ψ_b) with reduced serosal Cl concentrations, [Cl]_s. …

Electrophysiology Of Flounder Intestinal Mucosa. Ii. Relation Of The Electrical Potential Profile To Coupled Nacl Absorption, Dan R. Halm, Edward J. Krasny Jr., Raymond A. Frizzell

Neuroscience, Cell Biology & Physiology Faculty Publications

We characterized the hyperpolarization of the electrical potential profile of flounder intestinal cells that accompanies inhibition of NaCl cotransport. Several observations indicate that hyperpolarization of ψ_a and ψ_b (Δψ_a,b) results from inhibition of NaCl entry across the apical membrane: (a) the response was elicited by replacement of mucosal solution Cl or Na by nontransported ions, and (b) mucosal bumetanide or serosal cGMP, inhibitors of NaCl influx, elicited Δψ_a,b and decreased the transepithelial potential (ψ_t) in parallel. Regardless of initial values, ψ_a and ψ_b approached the equilibrium potential for K (E^{K …}

Metabolism In Preimplantation Mouse Embryos, Harry M. Weitlauf, Gary L. Nieder

Neuroscience, Cell Biology & Physiology Faculty Publications

The ability of preimplantation mouse embryos to utilize glucose oxidatively is controlled, in part at least, at the level of glycolysis. Various experimental observations are reviewed that indicate the regulatory mechanism in delayed implanting blastocysts involves the classic negative allosteric feedback of high levels of ATP on phosphofructokinase while the situation in 2-cell embryos appears to be more complicated. That is, in addition to the usual negative effect of ATP and citrate on phosphofructokinase, there appears to be a modification of hexokinase that prevents phosphorylation of adequate amounts of glucose and results in low levels of fructose-6-phosphate at the 2-cell …

Physiology And Pharmacology: 1905-1977; Physiology: 1977-1983, Helge Ellis Ederstrom, Stanley J. Brumleve

UND Departmental Histories

This departmental history was written on the occasion of the UND Centennial in 1983.

Effects Of The Serotonin Depletor Parachlorophenylalanine Upon Shock-Induced Aggression And Pressing Responses In Rats, Robert G. Sewell

Masters Theses

The literature concerning the effects of d, l-parachlorophenylalanine (PCPA) upon shock-induced aggression (SIA) is reviewed and found to be inconsistent. PCPA, a known serotonin depletor, has behavioral effects in a variety of other procedures which collectively suggest that PCPA should produce SIA enhancement. The present study was designed to analyze PCPA (300 mg/kg) effects upon SIA in rats restrained spatially close to an inanimate target and panel operandum. The results showed marked increases in both aggressive biting and panel pressing for several days following each PCPA treatment for each subject tested. These data were interpreted to indicate that serotonin depletion …

Effects Of Withdrawing Diphenylhydantoin (Dilantin) On Matching To Sample Performance In Mentally Retarded Persons, Vicky June Davis

Masters Theses

The present study was designed to examine the effects of gradual DPH withdrawal on the matching to sample performance of three mentally retarded persons. The percentage of correct responses per session served as the dependent variable and the sample and comparison stimuli were red, green, and blue illumination of translucent response windows. The results showed that doses of diphenylhydantoin considerably lower than the suggested optimim therapeutic level can impair the performance of mentally retarded individuals on a simple discrimination task. As doses were reduced for each subject, there were increases in the percentage of correct responding with the highest percentage …

The Improvement Of Peripheral Blood Flow During Hemorrhagic Hypotension Following Phenoxybenzamine Treatment Expressed In Terms Of Extracellular Potassium Shifts, Thomas J. Wera

Master's Essays (1922 - )

The study of plasma electrolytes notably, the potassium and sodium ions during hemorrhagic stress and other forms of shock, were once the subject of intense investigation (42). However, the advent of new investigative techniques enabled more complex, experimental designs and methods to be used in which it was possible to study the many other variables which exist as a result of shock regardless of cause. The proponents of the probable electrolyte mechanism in shock subsequently diminished in numbers until recent times.

It is felt by this author that recent renewal regarding the various ions, especially the cations, sodium and potassium …