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Articles 61 - 90 of 111

Full-Text Articles in Physiology

Analgesic Tolerance Of Opioid Agonists In Mutant Mu-Opioid Receptors Expressed In Sensory Neurons Following Intrathecal Plasmid Gene Delivery, Guangwen Li, Fei Ma, Yanping Gu, Li-Yen Mae Huang Dec 2013

Analgesic Tolerance Of Opioid Agonists In Mutant Mu-Opioid Receptors Expressed In Sensory Neurons Following Intrathecal Plasmid Gene Delivery, Guangwen Li, Fei Ma, Yanping Gu, Li-Yen Mae Huang

Physiology Faculty Publications

Background: Phosphorylation sites in the C-terminus of mu-opioid receptors (MORs) are known to play critical roles in the receptor functions. Our understanding of their participation in opioid analgesia is mostly based on studies of opioid effects on mutant receptors expressed in in vitro preparations, including cell lines, isolated neurons and brain slices. The behavioral consequences of the mutation have not been fully explored due to the complexity in studies of mutant receptors in vivo. To facilitate the determination of the contribution of phosphorylation sites in MOR to opioid-induced analgesic behaviors, we expressed mutant and wild-type human MORs (hMORs) in sensory …


Colour And Odour Drive Fruit Selection And Seed Dispersal By Mouse Lemurs, Kim Valenta, Ryan J. Burke, Sarah A. Styler, Derek A. Jackson, Amanda D. Melin, Shawn M. Lehman Aug 2013

Colour And Odour Drive Fruit Selection And Seed Dispersal By Mouse Lemurs, Kim Valenta, Ryan J. Burke, Sarah A. Styler, Derek A. Jackson, Amanda D. Melin, Shawn M. Lehman

Dartmouth Scholarship

Animals and fruiting plants are involved in a complex set of interactions, with animals relying on fruiting trees as food resources, and fruiting trees relying on animals for seed dispersal. This interdependence shapes fruit signals such as colour and odour, to increase fruit detectability, and animal sensory systems, such as colour vision and olfaction to facilitate food identification and selection. Despite the ecological and evolutionary importance of plant-animal interactions for shaping animal sensory adaptations and plant characteristics, the details of the relationship are poorly understood. Here we examine the role of fruit chromaticity, luminance and odour on seed dispersal by …


Derivation Of Multivariate Syndromic Outcome Metrics For Consistent Testing Across Multiple Models Of Cervical Spinal Cord Injury In Rats, Adam R. Ferguson, Karen-Amanda Irvine, John C. Gensel, Jessica L. Nielson, Amity Lin, Johnathan Ly, Mark R. Segal, Rajiv R. Ratan, Jacqueline C. Bresnahan, Michael S. Beattie Mar 2013

Derivation Of Multivariate Syndromic Outcome Metrics For Consistent Testing Across Multiple Models Of Cervical Spinal Cord Injury In Rats, Adam R. Ferguson, Karen-Amanda Irvine, John C. Gensel, Jessica L. Nielson, Amity Lin, Johnathan Ly, Mark R. Segal, Rajiv R. Ratan, Jacqueline C. Bresnahan, Michael S. Beattie

Physiology Faculty Publications

Spinal cord injury (SCI) and other neurological disorders involve complex biological and functional changes. Well-characterized preclinical models provide a powerful tool for understanding mechanisms of disease; however managing information produced by experimental models represents a significant challenge for translating findings across research projects and presents a substantial hurdle for translation of novel therapies to humans. In the present work we demonstrate a novel 'syndromic' information-processing approach for capitalizing on heterogeneous data from diverse preclinical models of SCI to discover translational outcomes for therapeutic testing. We first built a large, detailed repository of preclinical outcome data from 10 years of basic …


Loss Of Dendritic Inhibition In The Hippocampus After Repeated Early-Life Hyperthermic Seizures In Rats., Richard Boyce, L Stan Leung Jan 2013

Loss Of Dendritic Inhibition In The Hippocampus After Repeated Early-Life Hyperthermic Seizures In Rats., Richard Boyce, L Stan Leung

Physiology and Pharmacology Publications

Seizures are relatively common in children and are a risk factor for subsequent temporal lobe epilepsy. To investigate whether early-life seizures themselves are detrimental to the proper function of the adult brain, we studied whether dendritic excitation and inhibition in the hippocampus of adult rats were altered after hyperthermia-induced seizures in immature rats. In particular, we hypothesized that apical dendritic inhibition in hippocampal CA1 pyramidal cells would be disrupted following hyperthermia-induced seizures in early life. Seizure rats were given three hyperthermia-induced seizures per day for three days from postnatal day (PND) 13 to 15; control rats were handled similarly but …


Effect Of Muscle Length On Cross-Bridge Kinetics In Intact Cardiac Trabeculae At Body Temperature, Nima Milani-Nejad, Ying Xu, Jonathan P. Davis, Kenneth S. Campbell, Paul M. L. Janssen Dec 2012

Effect Of Muscle Length On Cross-Bridge Kinetics In Intact Cardiac Trabeculae At Body Temperature, Nima Milani-Nejad, Ying Xu, Jonathan P. Davis, Kenneth S. Campbell, Paul M. L. Janssen

Physiology Faculty Publications

Dynamic force generation in cardiac muscle, which determines cardiac pumping activity, depends on both the number of sarcomeric cross-bridges and on their cycling kinetics. The Frank–Starling mechanism dictates that cardiac force development increases with increasing cardiac muscle length (corresponding to increased ventricular volume). It is, however, unclear to what extent this increase in cardiac muscle length affects the rate of cross-bridge cycling. Previous studies using permeabilized cardiac preparations, sub-physiological temperatures, or both have obtained conflicting results. Here, we developed a protocol that allowed us to reliably and reproducibly measure the rate of tension redevelopment (ktr; which depends …


Orofacial Neuropathic Pain Mouse Model Induced By Trigeminal Inflammatory Compression (Tic) Of The Infraorbital Nerve, Fei Ma, Liping Zhang, Danielle Lyons, Karin N. Westlund Dec 2012

Orofacial Neuropathic Pain Mouse Model Induced By Trigeminal Inflammatory Compression (Tic) Of The Infraorbital Nerve, Fei Ma, Liping Zhang, Danielle Lyons, Karin N. Westlund

Physiology Faculty Publications

BACKGROUND: Trigeminal neuropathic pain attacks can be excruciating for patients, even after being lightly touched. Although there are rodent trigeminal nerve research models to study orofacial pain, few models have been applied to studies in mice. A mouse trigeminal inflammatory compression (TIC) model is introduced here which successfully and reliably promotes vibrissal whisker pad hypersensitivity.

RESULTS: The chronic orofacial neuropathic pain model is induced after surgical placement of chromic gut suture in the infraorbital nerve fissure in the maxillary bone. Slight compression and chemical effects of the chromic gut suture on the portion of the infraorbital nerve contacted cause mild …


A Novel Method For Comparative Analysis Of Retinal Specialization Traits From Topographic Maps, Bret A. Moore, Jason M. Kamilar, Shaun P. Collin, Olaf R. P. Bininda-Emonds, Nathaniel J. Dominy, Margaret I. Hall, Christopher P. Hessy, Sonke Johnsen, Thomas J. Lisney, Ellis R. Loew, Gillian Moritz Nov 2012

A Novel Method For Comparative Analysis Of Retinal Specialization Traits From Topographic Maps, Bret A. Moore, Jason M. Kamilar, Shaun P. Collin, Olaf R. P. Bininda-Emonds, Nathaniel J. Dominy, Margaret I. Hall, Christopher P. Hessy, Sonke Johnsen, Thomas J. Lisney, Ellis R. Loew, Gillian Moritz

Dartmouth Scholarship

Abstract Vertebrates possess different types of retinal specializations that vary in number, size, shape, and position in the retina. This diversity in retinal configuration has been revealed through topographic maps, which show variations in neuron density across the retina. Although topographic maps of about 300 vertebrates are available, there is no method for characterizing retinal traits quantitatively. Our goal is to present a novel method to standardize information on the position of the retinal specializations and changes in retinal ganglion cell (RGC) density across the retina from published topographic maps. We measured the position of the retinal specialization using two …


Characterization Of Secretory Sphingomyelinase Activity, Lipoprotein Sphingolipid Content And Ldl Aggregation In Ldlr-/- Mice Fed On A High-Fat Diet, Gergana M. Deevska, Manjula Sunkara, Andrew J. Morris, Mariana N. Nikolova‑Karakashian Oct 2012

Characterization Of Secretory Sphingomyelinase Activity, Lipoprotein Sphingolipid Content And Ldl Aggregation In Ldlr-/- Mice Fed On A High-Fat Diet, Gergana M. Deevska, Manjula Sunkara, Andrew J. Morris, Mariana N. Nikolova‑Karakashian

Physiology Faculty Publications

The propensity of LDLs (low-density lipoproteins) for aggregation and/or oxidation has been linked to their sphingolipid content, specifically the levels of SM (sphingomyelin) and ceramide. To investigate this association in vivo, ldlr (LDL receptor)-null mice (ldlr-/-) were fed on a modified (atherogenic) diet containing saturated fats and cholesterol. The diet led to significantly elevated SM content in all serum lipoproteins. In contrast, ceramide increased only in the LDL particles. MS-based analyses of the lipid acyl chain composition revealed a marked elevation in C16:0 fatty acid in SM and ceramide, consistent with the prevalence of palmitic acid in the modified diet. …


Endogenous Inhibitor Proteins That Connect Ser/Thr Kinases And Phosphatases In Cell Signaling., Masumi Eto, David L Brautigan Sep 2012

Endogenous Inhibitor Proteins That Connect Ser/Thr Kinases And Phosphatases In Cell Signaling., Masumi Eto, David L Brautigan

Department of Molecular Physiology and Biophysics Faculty Papers

Protein phosphatase activity acts as a primary determinant of the extent and duration of phosphorylation of cellular proteins in response to physiological stimuli. Ser/Thr protein phosphatase-1 (PP1) belongs to the PPP superfamily, and is associated with regulatory subunits that confer substrate specificity, allosteric regulation, and subcellular compartmentalization. In addition, all eukaryotic cells contain multiple heat-stable proteins that originally were thought to inhibit phosphatase catalytic subunits released from the regulatory subunits, as a fail-safe mechanism. However, discovery of C-kinase-activated PP1 inhibitor, Mr of 17 kDa (CPI-17) required fresh thinking about the endogenous inhibitors as specific regulators of particular phosphatase complexes, acting …


Atovaquone Ameliorate Gastrointestinal Toxoplasmosis Complications In A Pregnancy Model, Helieh S. Oz, Thomas Tobin Sep 2012

Atovaquone Ameliorate Gastrointestinal Toxoplasmosis Complications In A Pregnancy Model, Helieh S. Oz, Thomas Tobin

Physiology Faculty Publications

Background: Toxoplasma is an important source of foodborne hospitalization with no safe and effective therapy against chronic or congenital Toxopalsmosis. Atovaquone is a drug of choice but not approved for use in congenital Toxoplasmosis. We hypothesized atovaquone to be safe and effective against feto-maternal Toxoplasmosis.

Material/Methods: Programmed pregnant mice were i.p. infected with 50–2400 Tachyzoites from Type II strain (clone PTG). Dams were treated daily with atovaquone or sham and monitored for pain, and complications.

Results: Dams developed pain related abdominal hypersensitivity (allodynia) to mechanical stimuli in a Tachyzoites dose dependent manner. Infected dams were anemic and exhibited ascities and …


Genomics Of Mature And Immature Olfactory Sensory Neurons, Melissa D. Nickell, Patrick Breheny, Arnold J. Stromberg, Timothy S. Mcclintock Aug 2012

Genomics Of Mature And Immature Olfactory Sensory Neurons, Melissa D. Nickell, Patrick Breheny, Arnold J. Stromberg, Timothy S. Mcclintock

Physiology Faculty Publications

The continuous replacement of neurons in the olfactory epithelium provides an advantageous model for investigating neuronal differentiation and maturation. By calculating the relative enrichment of every mRNA detected in samples of mature mouse olfactory sensory neurons (OSNs), immature OSNs, and the residual population of neighboring cell types, and then comparing these ratios against the known expression patterns of >300 genes, enrichment criteria that accurately predicted the OSN expression patterns of nearly all genes were determined. We identified 847 immature OSN-specific and 691 mature OSN-specific genes. The control of gene expression by chromatin modification and transcription factors, and neurite growth, protein …


Peripheral Nerve Injury Increases Glutamate-Evoked Calcium Mobilization In Adult Spinal Cord Neurons, Suzanne Doolen, Camille B. Blake, Bret N. Smith, Bradley K. Taylor Jul 2012

Peripheral Nerve Injury Increases Glutamate-Evoked Calcium Mobilization In Adult Spinal Cord Neurons, Suzanne Doolen, Camille B. Blake, Bret N. Smith, Bradley K. Taylor

Physiology Faculty Publications

BACKGROUND: Central sensitization in the spinal cord requires glutamate receptor activation and intracellular Ca2+ mobilization. We used Fura-2 AM bulk loading of mouse slices together with wide-field Ca2+ imaging to measure glutamate-evoked increases in extracellular Ca2+ to test the hypotheses that: 1. Exogenous application of glutamate causes Ca2+ mobilization in a preponderance of dorsal horn neurons within spinal cord slices taken from adult mice; 2. Glutamate-evoked Ca2+ mobilization is associated with spontaneous and/or evoked action potentials; 3. Glutamate acts at glutamate receptor subtypes to evoked Ca2+ transients; and 4. The magnitude of glutamate-evoked Ca2+ responses increases in the setting of …


Early Stage Drug Treatment That Normalizes Proinflammatory Cytokine Production Attenuates Synaptic Dysfunction In A Mouse Model That Exhibits Age-Dependent Progression Of Alzheimer's Disease-Related Pathology, Adam D. Bachstetter, Christopher M. Norris, Pradoldej Sompol, Donna M. Wilcock, Danielle Goulding, Janna H. Neltner, Daret St. Clair, D. Martin Watterson, Linda J. Van Eldik Jul 2012

Early Stage Drug Treatment That Normalizes Proinflammatory Cytokine Production Attenuates Synaptic Dysfunction In A Mouse Model That Exhibits Age-Dependent Progression Of Alzheimer's Disease-Related Pathology, Adam D. Bachstetter, Christopher M. Norris, Pradoldej Sompol, Donna M. Wilcock, Danielle Goulding, Janna H. Neltner, Daret St. Clair, D. Martin Watterson, Linda J. Van Eldik

Sanders-Brown Center on Aging Faculty Publications

Overproduction of proinflammatory cytokines in the CNS has been implicated as a key contributor to pathophysiology progression in Alzheimer's disease (AD), and extensive studies with animal models have shown that selective suppression of excessive glial proinflammatory cytokines can improve neurologic outcomes. The prior art, therefore, raises the logical postulation that intervention with drugs targeting dysregulated glial proinflammatory cytokine production might be effective disease-modifying therapeutics if used in the appropriate biological time window. To test the hypothesis that early stage intervention with such drugs might be therapeutically beneficial, we examined the impact of intervention with MW01-2-151SRM (MW-151), an experimental therapeutic that …


Mice Deficient In Gem Gtpase Show Abnormal Glucose Homeostasis Due To Defects In Beta-Cell Calcium Handling, Jenny E. Gunton, Mary Sisavanh, Rebecca A. Stokes, Jon Satin, Leslie S. Satin, Min Zhang, Sue M. Liu, Weikang Cai, Kim Cheng, Gregory J. Cooney, D. Ross Laybutt, Trina So, Juan-Carlos Molero, Shane T. Grey, Douglas A. Andres, Michael S. Rolph, Charles R. Mackay Jun 2012

Mice Deficient In Gem Gtpase Show Abnormal Glucose Homeostasis Due To Defects In Beta-Cell Calcium Handling, Jenny E. Gunton, Mary Sisavanh, Rebecca A. Stokes, Jon Satin, Leslie S. Satin, Min Zhang, Sue M. Liu, Weikang Cai, Kim Cheng, Gregory J. Cooney, D. Ross Laybutt, Trina So, Juan-Carlos Molero, Shane T. Grey, Douglas A. Andres, Michael S. Rolph, Charles R. Mackay

Physiology Faculty Publications

AIMS AND HYPOTHESIS: Glucose-stimulated insulin secretion from beta-cells is a tightly regulated process that requires calcium flux to trigger exocytosis of insulin-containing vesicles. Regulation of calcium handling in beta-cells remains incompletely understood. Gem, a member of the RGK (Rad/Gem/Kir) family regulates calcium channel handling in other cell types, and Gem over-expression inhibits insulin release in insulin-secreting Min6 cells. The aim of this study was to explore the role of Gem in insulin secretion. We hypothesised that Gem may regulate insulin secretion and thus affect glucose tolerance in vivo.

METHODS: Gem-deficient mice were generated and their metabolic phenotype characterised by in …


Ipla2Β Overexpression In Smooth Muscle Exacerbates Angiotensin Ii-Induced Hypertension And Vascular Remodeling, Lindsay E Calderon, Shu Liu, Wen Su, Zhongwen Xie, Zhenheng Guo, Wanda Eberhard, Ming C. Gong Feb 2012

Ipla2Β Overexpression In Smooth Muscle Exacerbates Angiotensin Ii-Induced Hypertension And Vascular Remodeling, Lindsay E Calderon, Shu Liu, Wen Su, Zhongwen Xie, Zhenheng Guo, Wanda Eberhard, Ming C. Gong

Physiology Faculty Publications

OBJECTIVES: Calcium independent group VIA phospholipase A2 (iPLA2β) is up-regulated in vascular smooth muscle cells in some diseases, but whether the up-regulated iPLA2β affects vascular morphology and blood pressure is unknown. The current study addresses this question by evaluating the basal- and angiotensin II infusion-induced vascular remodeling and hypertension in smooth muscle specific iPLA2β transgenic (iPLA2β-Tg) mice.

METHOD AND RESULTS: Blood pressure was monitored by radiotelemetry and vascular remodeling was assessed by morphologic analysis. We found that the angiotensin II-induced increase in diastolic pressure was significantly higher in iPLA2β-Tg …


Minimum Cost Of Transport In Asian Elephants: Do We Really Need A Bigger Elephant?, V. A. Langman, M. F. Rowe, T. J. Roberts, N. V. Langman, C. R. Taylor Jan 2012

Minimum Cost Of Transport In Asian Elephants: Do We Really Need A Bigger Elephant?, V. A. Langman, M. F. Rowe, T. J. Roberts, N. V. Langman, C. R. Taylor

Dartmouth Scholarship

Body mass is the primary determinant of an animal’s energy requirements. At their optimum walking speed, large animals have lower mass-specific energy requirements for locomotion than small ones. In animals ranging in size from 0.8 g (roach) to 260 kg (zebu steer), the minimum cost of transport (COTmin) decreases with increasing body size roughly as COTmin∝body mass (Mb)–0.316±0.023 (95% CI). Typically, the variation of COTmin with body mass is weaker at the intraspecific level as a result of physiological and geometric similarity within closely related species. The interspecific relationship estimates that …


Nutrition, Inflammation, And Infectious Disease, Helieh S. Oz, Sung-Ling Yeh Jan 2012

Nutrition, Inflammation, And Infectious Disease, Helieh S. Oz, Sung-Ling Yeh

Physiology Faculty Publications

No abstract provided.


Pegylated Arginine Deiminase Downregulates Colitis In Murine Models, Helieh S. Oz, Jian Zhong, Willem J. S. De Villiers Jan 2012

Pegylated Arginine Deiminase Downregulates Colitis In Murine Models, Helieh S. Oz, Jian Zhong, Willem J. S. De Villiers

Physiology Faculty Publications

Arginine deiminase (ADI), an arginine-metabolizing enzyme involved in cell signaling, is dysregulated in multiple inflammatory diseases and cancers. We hypothesized that pegylated ADI (ADI-PEG) provide protection against colitis.

METHODS: Dextran sodium sulfate colitis was induced in IL-10-deficient and BALB/c (WT) mice. ADI-PEG was administered i.p., and inflammatory mediators and pathology were evaluated.

RESULTS: Acute colitis in mice was manifested by increases in inflammatory biomarkers, such as serum amyloid A (SAA, P < 0.001), IL-12 p40, and disease index (3-Fold). In contrast, ADI-PEG significantly decreased clinical disease index, SAA levels, and inflammatory cytokines in blood as well as in colonic explants. Animals developed moderate (2.2 ± 0.3 WT) to severe (3.6 ± 0.5 IL-10 deficient) colonic pathology; and ADI-PEG treatment significantly improved the severity of colitis (P < 0.05). Marked infiltration of CD68+ macrophages and iNOS expression were detected in colonic submucosa in colitic animals but not detected in ADI-PEG-treated animals.

CONCLUSION: ADI-PEG attenuated inflammatory responses by suppression of macrophage infiltration and iNOS expression in colitic animals. ADI-PEG can serve as a potential therapeutic value in IBD.


Age-Associated Disruption Of Molecular Clock Expression In Skeletal Muscle Of The Spontaneously Hypertensive Rat, Mitsunori Miyazaki, Elizabeth Schroder, Stephanie E. Edelmann, Michael E. Hughes, Karl Kornacker, C. William Balke, Karyn A. Esser Nov 2011

Age-Associated Disruption Of Molecular Clock Expression In Skeletal Muscle Of The Spontaneously Hypertensive Rat, Mitsunori Miyazaki, Elizabeth Schroder, Stephanie E. Edelmann, Michael E. Hughes, Karl Kornacker, C. William Balke, Karyn A. Esser

Physiology Faculty Publications

It is well known that spontaneously hypertensive rats (SHR) develop muscle pathologies with hypertension and heart failure, though the mechanism remains poorly understood. Woon et al. (2007) linked the circadian clock gene Bmal1 to hypertension and metabolic dysfunction in the SHR. Building on these findings, we compared the expression pattern of several core-clock genes in the gastrocnemius muscle of aged SHR (80 weeks; overt heart failure) compared to aged-matched control WKY strain. Heart failure was associated with marked effects on the expression of Bmal1, Clock and Rora in addition to several non-circadian genes important in regulating skeletal muscle phenotype including …


A Mathematical Model Of Muscle Containing Heterogeneous Half-Sarcomeres Exhibits Residual Force Enhancement, Stuart G. Campbell, P. Chris Hatfield, Kenneth S. Campbell Sep 2011

A Mathematical Model Of Muscle Containing Heterogeneous Half-Sarcomeres Exhibits Residual Force Enhancement, Stuart G. Campbell, P. Chris Hatfield, Kenneth S. Campbell

Physiology Faculty Publications

A skeletal muscle fiber that is stimulated to contract and then stretched from L₁ to L₂ produces more force after the initial transient decays than if it is stimulated at L₂. This behavior has been well studied experimentally, and is known as residual force enhancement. The underlying mechanism remains controversial. We hypothesized that residual force enhancement could reflect mechanical interactions between heterogeneous half-sarcomeres. To test this hypothesis, we subjected a computational model of interacting heterogeneous half-sarcomeres to the same activation and stretch protocols that produce residual force enhancement in real preparations. Following a transient period of elevated force associated with …


Functional Plasticity Of Central Trpv1 Receptors In Brainstem Dorsal Vagal Complex Circuits Of Streptozotocin-Treated Hyperglycemic Mice, Andrea Zsombok, Muthu D. Bhaskaran, Hong Gao, Andrei V. Derbenev, Bret N. Smith Sep 2011

Functional Plasticity Of Central Trpv1 Receptors In Brainstem Dorsal Vagal Complex Circuits Of Streptozotocin-Treated Hyperglycemic Mice, Andrea Zsombok, Muthu D. Bhaskaran, Hong Gao, Andrei V. Derbenev, Bret N. Smith

Physiology Faculty Publications

Emerging data indicate that central neurons participate in diabetic processes by modulating autonomic output from neurons in the dorsal motor nucleus of the vagus (DMV). We tested the hypothesis that synaptic modulation by transient receptor potential vanilloid type 1 (TRPV1) receptors is reduced in the DMV in slices from a murine model of type 1 diabetes. The TRPV1 agonist capsaicin robustly enhanced glutamate release onto DMV neurons by acting at preterminal receptors in slices from intact mice, but failed to do so in slices from diabetic mice. TRPV1 receptor protein expression in the vagal complex was unaltered. Brief insulin preapplication …


Store-Operated Ca(2+) Entry (Soce) Contributes To Normal Skeletal Muscle Contractility In Young But Not In Aged Skeletal Muscle, Angela M. Thornton, Xiaoli Zhao, Noah Weisleder, Leticia S. Brotto, Sylvain Bougoin, Thomas M. Nosek, Michael B. Reid, Brian Hardin, Zui Pan, Jianjie Ma, Jerome Parness, Marco Brotto Jun 2011

Store-Operated Ca(2+) Entry (Soce) Contributes To Normal Skeletal Muscle Contractility In Young But Not In Aged Skeletal Muscle, Angela M. Thornton, Xiaoli Zhao, Noah Weisleder, Leticia S. Brotto, Sylvain Bougoin, Thomas M. Nosek, Michael B. Reid, Brian Hardin, Zui Pan, Jianjie Ma, Jerome Parness, Marco Brotto

Physiology Faculty Publications

Muscle atrophy alone is insufficient to explain the significant decline in contractile force of skeletal muscle during normal aging. One contributing factor to decreased contractile force in aging skeletal muscle could be compromised excitation-contraction (E-C) coupling, without sufficient available Ca(2+) to allow for repetitive muscle contractility, skeletal muscles naturally become weaker. Using biophysical approaches, we previously showed that store-operated Ca(2+) entry (SOCE) is compromised in aged skeletal muscle but not in young ones. While important, a missing component from previous studies is whether or not SOCE function correlates with contractile function during aging. Here we test the contribution of extracellular …


Synaptic Reorganization Of Inhibitory Hilar Interneuron Circuitry After Traumatic Brain Injury In Mice, Robert F. Hunt, Stephen W. Scheff, Bret N. Smith May 2011

Synaptic Reorganization Of Inhibitory Hilar Interneuron Circuitry After Traumatic Brain Injury In Mice, Robert F. Hunt, Stephen W. Scheff, Bret N. Smith

Physiology Faculty Publications

Functional plasticity of synaptic networks in the dentate gyrus has been implicated in the development of posttraumatic epilepsy and in cognitive dysfunction after traumatic brain injury, but little is known about potentially pathogenic changes in inhibitory circuits. We examined synaptic inhibition of dentate granule cells and excitability of surviving GABAergic hilar interneurons 8–13 weeks after cortical contusion brain injury in transgenic mice that express enhanced green fluorescent protein in a subpopulation of inhibitory neurons. Whole-cell voltage-clamp recordings in granule cells revealed a reduction in spontaneous and miniature IPSC frequency after head injury; no concurrent change in paired-pulse ratio was found …


Cholinergic Modulation Of Narcoleptic Attacks In Double Orexin Receptor Knockout Mice, Mike Kalogiannis, Emily Hsu, Jon Willie, Richard Chemelli, Yaz Kisanuki, Masashi Yanagisawa, Christopher S. Leonard Apr 2011

Cholinergic Modulation Of Narcoleptic Attacks In Double Orexin Receptor Knockout Mice, Mike Kalogiannis, Emily Hsu, Jon Willie, Richard Chemelli, Yaz Kisanuki, Masashi Yanagisawa, Christopher S. Leonard

NYMC Faculty Publications

To investigate how cholinergic systems regulate aspects of the sleep disorder narcolepsy, we video-monitored mice lacking both orexin (hypocretin) receptors (double knockout; DKO mice) while pharmacologically altering cholinergic transmission. Spontaneous behavioral arrests in DKO mice were highly similar to those reported in orexin-deficient mice and were never observed in wild-type (WT) mice. A survival analysis revealed that arrest lifetimes were exponentially distributed indicating that random, Markovian processes determine arrest lifetime. Low doses (0.01, 0.03 mg/kg, i.p.), but not a high dose (0.08 mg/kg, i.p.) of the cholinesterase inhibitor physostigmine increased the number of arrests but did not alter arrest lifetimes. …


Association Between Chronic Liver And Colon Inflammation During The Development Of Murine Syngeneic Graft-Versus-Host Disease, Jason Anthony Brandon, Jacqueline Perez-Rodriguez, C. Darrell Jennings, Donald A. Cohen, Vishal J. Sindhava, Subbarao Bondada, Alan M. Kaplan, J. Scott Bryson Sep 2010

Association Between Chronic Liver And Colon Inflammation During The Development Of Murine Syngeneic Graft-Versus-Host Disease, Jason Anthony Brandon, Jacqueline Perez-Rodriguez, C. Darrell Jennings, Donald A. Cohen, Vishal J. Sindhava, Subbarao Bondada, Alan M. Kaplan, J. Scott Bryson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The murine model of cyclosporine A (CsA)-induced syngeneic graft-versus-host disease (SGVHD) is a bone marrow (BM) transplantation model that develops chronic colon inflammation identical to other murine models of CD4+ T cell-mediated colitis. Interestingly, SGVHD animals develop chronic liver lesions that are similar to the early peribiliary inflammatory stages of clinical chronic liver disease, which is frequently associated with inflammatory bowel disease (IBD). Therefore, studies were initiated to investigate the chronic liver inflammation that develops in the SGVHD model. To induce SGVHD, mice were lethally irradiated, reconstituted with syngeneic BM, and treated with CsA. All of the SGVHD animals …


Mip/Mtmr14 And Muscle Aging, Scott K. Powers, Michael B. Reid Sep 2010

Mip/Mtmr14 And Muscle Aging, Scott K. Powers, Michael B. Reid

Physiology Faculty Publications

No abstract.


Poisonous Rangeland Plants In San Luis Obispo County, Sara Litten, Amanda Ou Jun 2010

Poisonous Rangeland Plants In San Luis Obispo County, Sara Litten, Amanda Ou

Animal Science

Poisonous Rangeland Plants in San Luis Obispo County is a comprehensive educational guide to rangeland plants that are toxic to domestic livestock. This guide begins with an exploration of how the biological systems are affected by the poisonous plant toxins. The biochemistry behind these toxins is included in the discussion. Next, reference material for fourteen plants that inhabit San Luis Obispo County is provided. This information includes specific toxins found in poisonous plants, affected animals, symptoms of poisoning, stages of growth, lethal dose, and distribution of the plant in California. This section of the guide is filled with helpful photos …


Cannabinoid-Mediated Inhibition Of Recurrent Excitatory Circuitry In The Dentate Gyrus In A Mouse Model Of Temporal Lobe Epilepsy, Muthu D. Bhaskaran, Bret N. Smith May 2010

Cannabinoid-Mediated Inhibition Of Recurrent Excitatory Circuitry In The Dentate Gyrus In A Mouse Model Of Temporal Lobe Epilepsy, Muthu D. Bhaskaran, Bret N. Smith

Physiology Faculty Publications

Temporal lobe epilepsy (TLE) is a neurological condition associated with neuron loss, axon sprouting, and hippocampal sclerosis, which results in modified synaptic circuitry. Cannabinoids appear to be anti-convulsive in patients and animal models of TLE, but the mechanisms of this effect are not known. A pilocarpine-induced status epilepticus mouse model of TLE was used to study the effect of cannabinoid agonists on recurrent excitatory circuits of the dentate gyrus using electrophysiological recordings in hippocampal slices isolated from control mice and mice with TLE. Cannabinoid agonists WIN 55,212-2, anandamide (AEA), or 2-arachydonoylglycerol (2-AG) reduced the frequency of spontaneous and tetrodotoxin-resistant excitatory …


Genomic Profiling Of Messenger Rnas And Micrornas Reveals Potential Mechanisms Of Tweak-Induced Skeletal Muscle Wasting In Mice, Siva K. Panguluri, Shephali Bhatnagar, Akhilesh Kumar, John J. Mccarthy, Apurva K. Srivastava, Nigel G. Cooper, Robert F. Lundy, Ashok Kumar Jan 2010

Genomic Profiling Of Messenger Rnas And Micrornas Reveals Potential Mechanisms Of Tweak-Induced Skeletal Muscle Wasting In Mice, Siva K. Panguluri, Shephali Bhatnagar, Akhilesh Kumar, John J. Mccarthy, Apurva K. Srivastava, Nigel G. Cooper, Robert F. Lundy, Ashok Kumar

Physiology Faculty Publications

BACKGROUND: Skeletal muscle wasting is a devastating complication of several physiological and pathophysiological conditions. Inflammatory cytokines play an important role in the loss of skeletal muscle mass in various chronic diseases. We have recently reported that proinflammatory cytokine TWEAK is a major muscle-wasting cytokine. Emerging evidence suggests that gene expression is regulated not only at transcriptional level but also at post-transcriptional level through the expression of specific non-coding microRNAs (miRs) which can affect the stability and/or translation of target mRNA. However, the role of miRs in skeletal muscle wasting is unknown.

METHODOLOGY/PRINCIPAL FINDINGS: To understand the mechanism of action of …


Impact Of Central And Peripheral Trpv1 And Ros Levels On Proinflammatory Mediators And Nociceptive Behavior, Karin N. Westlund, Mikhail Y. Kochukov, Ying Lu, Terry A. Mcnearney Jan 2010

Impact Of Central And Peripheral Trpv1 And Ros Levels On Proinflammatory Mediators And Nociceptive Behavior, Karin N. Westlund, Mikhail Y. Kochukov, Ying Lu, Terry A. Mcnearney

Physiology Faculty Publications

Background: Transient receptor potential vanilloid 1 (TRPV1) channels are important membrane sensors on peripheral nerve endings and on supportive non-neuronal synoviocytes in the knee joint. TRPV 1 ion channels respond with activation of calcium and sodium fluxes to pH, thermal, chemical, osmotic, mechanical and other stimuli abundant in inflamed joints. In the present study, the kaolin/carrageenan (k/c) induced knee joint arthritis model in rats, as well as primary and clonal human synoviocyte cultures were used to understand the reciprocal interactions between reactive nitroxidative species (ROS) and functional TRPV1 channels. ROS generation was monitored with ROS sensitive dyes using live cell …