keyword
https://read.qxmd.com/read/17448422/in-vivo-effects-of-myocardial-creatine-depletion-on-left-ventricular-function-morphology-and-energy-metabolism-consequences-in-acute-myocardial-infarction
#21
COMPARATIVE STUDY
Malin Lorentzon, Truls Råmunddal, Entela Bollano, Bassam Soussi, Finn Waagstein, Elmir Omerovic
BACKGROUND: The failing heart is characterized by disturbed myocardial energy metabolism and creatine (Cr) depletion. The aims of this study were to in vivo evaluate the effects of Cr depletion on: a) left ventricular (LV) function and morphology during rest and stress, b) LV energy metabolism, c) catecholamine in LV and plasma content, and d) incidence of malignant ventricular arrhythmias (MVA) during acute myocardial infarction (MI). METHODS AND RESULTS: Male rats weighing approximately 200 g were used...
April 2007: Journal of Cardiac Failure
https://read.qxmd.com/read/17276357/aging-associated-reductions-in-amp-activated-protein-kinase-activity-and-mitochondrial-biogenesis
#22
JOURNAL ARTICLE
Richard M Reznick, Haihong Zong, Ji Li, Katsutaro Morino, Irene K Moore, Hannah J Yu, Zhen-Xiang Liu, Jianying Dong, Kirsty J Mustard, Simon A Hawley, Douglas Befroy, Marc Pypaert, D Grahame Hardie, Lawrence H Young, Gerald I Shulman
Recent studies have demonstrated a strong relationship between aging-associated reductions in mitochondrial function, dysregulated intracellular lipid metabolism, and insulin resistance. Given the important role of the AMP-activated protein kinase (AMPK) in the regulation of fat oxidation and mitochondrial biogenesis, we examined AMPK activity in young and old rats and found that acute stimulation of AMPK-alpha(2) activity by 5'-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) and exercise was blunted in skeletal muscle of old rats...
February 2007: Cell Metabolism
https://read.qxmd.com/read/16781683/possible-role-of-creatine-concentrations-in-the-brain-in-regulating-appetite-and-weight
#23
COMPARATIVE STUDY
Richard A Galbraith, Masaru Furukawa, Muyao Li
Cobaltic protoporphyrin IX (CoPP) is a synthetic heme analog which can elicit profound and prolonged decreases in appetite and body weight in several different animal species. Intracerebroventricular administration of CoPP in rats was found, by differential display and confirmed by Real-Time PCR, to result in an increase in expression of the creatine transporter when compared to vehicle-treated fed or vehicle-treated fasted control animals. In situ hybridization studies showed that creatine transporter mRNA concentrations were increased in several areas of the brain involved in the regulation of food intake, but creatine concentrations were decreased in hypothalamic homogenates in CoPP-treated animals compared to controls...
July 26, 2006: Brain Research
https://read.qxmd.com/read/16460903/anisoin-a-useful-pre-chromatographic-derivatization-fluorogenic-reagent-for-lc-analysis-of-guanidino-compounds
#24
JOURNAL ARTICLE
R Gatti, M G Gioia
The use of anisoin as pre-chromatographic reagent for LC analysis of guanidino compounds is proposed. The reagent reacts (5 min at 100 degrees C) with guanidino function and the resulting adducts can be chromatographed under reversed-phase conditions. A fluorescence detector (lambda(ex)=325 nm; lambda(em)=435 nm) was used to detect guanidino adducts. The derivatization and chromatographic conditions were optimised by a series of experiments. Application to the determination of arginine and creatine in pharmaceuticals and arginine, guanidine, methylguanidine, guanidinosuccinic acid, beta-guanidinopropionic acid, gamma-guanidinobutyric acid, guanidinoacetic acid and homoarginine in human urine is described...
September 11, 2006: Journal of Pharmaceutical and Biomedical Analysis
https://read.qxmd.com/read/15329154/the-aminoguanidine-carboxylate-bvt-12777-activates-atp-sensitive-k-channels-in-the-rat-insulinoma-cell-line-cri-g1
#25
JOURNAL ARTICLE
Jackie M Kinsella, Hilary A Laidlaw, Teresa Tang, Jenni Harvey, Calum Sutherland, Michael L J Ashford
BACKGROUND: 3-guanidinopropionic acid derivatives reduce body weight in obese, diabetic mice. We have assessed whether one of these analogues, the aminoguanidine carboxylate BVT.12777, opens KATP channels in rat insulinoma cells, by the same mechanism as leptin. RESULTS: BVT.12777 hyperpolarized CRI-G1 rat insulinoma cells by activation of KATP channels. In contrast, BVT.12777 did not activate heterologously expressed pancreatic beta-cell KATP subunits directly...
August 24, 2004: BMC Pharmacology
https://read.qxmd.com/read/15147512/taurine-induced-long-lasting-potentiation-in-the-rat-hippocampus-shows-a-partial-dissociation-from-total-hippocampal-taurine-content-and-independence-from-activation-of-known-taurine-transporters
#26
JOURNAL ARTICLE
John Dominy, Jeffrey S Thinschmidt, Joanna Peris, Ralph Dawson, Roger L Papke
Perfusion with high millimolar levels of taurine evoked a long-lasting potentiation (LLP-TAU) of synaptic transmission in the Schaffer-collateral CA1 region of the rat hippocampus. Although LLP-TAU showed some correlations to increases in the total taurine content of hippocampal slices, it could not be blocked by the taurine transport inhibitor guanidinoethanesulfonic acid (GES), which was able to significantly reduce total slice taurine uptake. Inhibition of GABA transport by either nipecotic acid or beta-guanidinopropionate failed to abolish LLP-TAU and had no significant effect on taurine uptake...
June 2004: Journal of Neurochemistry
https://read.qxmd.com/read/15038837/metabolic-modulation-of-muscle-fiber-properties-unrelated-to-mechanical-stimuli
#27
JOURNAL ARTICLE
Yoshinobu Ohira, Fuminori Kawano, Roland R Roy, V Reggie Edgerton
The effects of chronically increasing (creatine-fed) or decreasing (beta-guanidinopropionic acid [beta-GPA]-fed) high-energy phosphates for up to 8 weeks on daily voluntary activity levels, swimming endurance capacity, electromyogram (EMG) activity, and the morphological and metabolic properties of single fibers in the soleus and extensor digitorum longus (EDL) muscles in young rats were determined. High-energy phosphate, voluntary activity, and soleus-integrated EMG levels were lower in beta-GPA-fed rats than in control rats...
December 2003: Japanese Journal of Physiology
https://read.qxmd.com/read/15018993/functional-characterization-of-sodium-and-chloride-dependent-taurine-transport-in-human-keratinocytes
#28
JOURNAL ARTICLE
Franziska Grafe, Wolfgang Wohlrab, Reinhard H Neubert, Matthias Brandsch
In the skin, taurine acts as an important osmolyte required for keratinocyte hydration. It has antioxidant effects, protects cells from UV-induced stress and has effects on cell proliferation, inflammation and collagenogenesis. This study was performed to find and characterize functionally a taurine transport system in keratinocytes and to establish a cell culture model for skin taurine transport studies. Uptake of [(3)H]taurine was studied both in the human adult low calcium high temperature (HaCaT) cell line and in human native epidermal keratinocytes...
March 2004: European Journal of Pharmaceutics and Biopharmaceutics
https://read.qxmd.com/read/14706115/stimulation-of-hsp72-expression-following-atp-depletion-and-short-term-exercise-training-in-fast-twitch-muscle
#29
JOURNAL ARTICLE
L Ecochard, D Roussel, B Sempore, R Favier
AIM: Previous data have reported increases in HSP72 expression in skeletal muscles after endurance training but the physiological and biochemical signals that induce HSP72 accumulation remain largely unknown. In this study, we tested the hypothesis that energy status is a key regulatory event for HSP72 accumulation in skeletal muscles. METHODS: Reduction of high-energy phosphate levels was induced by supplementation with a creatine analogue, beta-guanidinopropionic acid (GPA) for 3 weeks while control rats received distilled water in the same conditions...
January 2004: Acta Physiologica Scandinavica
https://read.qxmd.com/read/12701810/a-role-for-guanidino-compounds-in-the-brain
#30
REVIEW
Midori Hiramatsu
Guanidino compounds of guanidinoethanesulfonic acid, guanidinoacetic acid, guanidinosuccinic acid, N-acetylarginine, beta-guanidinopropionic acid, creatinine, gamma-guanidinobutyric acid, arginine, guanidine, methylguanidine, homoarginine and alpha-guanidinoglutaric acid are present in the mammalian brain. These guanidino compounds except for arginine and guanidine induce seizures and convulsions in rat, rabbit and cat by intracisternal injection. Hirudonine, audonine, alpha-keto-delta-guanidinovaleric acid, N,N'-dibenzoylguanidine and phenylethylguanidine are also convulsants...
February 2003: Molecular and Cellular Biochemistry
https://read.qxmd.com/read/12621025/inhibition-of-the-mitochondrial-permeability-transition-by-creatine-kinase-substrates-requirement-for-microcompartmentation
#31
JOURNAL ARTICLE
Max Dolder, Bernd Walzel, Oliver Speer, Uwe Schlattner, Theo Wallimann
Mitochondria from transgenic mice, expressing enzymatically active mitochondrial creatine kinase in liver, were analyzed for opening of the permeability transition pore in the absence and presence of creatine kinase substrates but with no external adenine nucleotides added. In mitochondria from these transgenic mice, cyclosporin A-inhibited pore opening was delayed by creatine or cyclocreatine but not by beta-guanidinopropionic acid. This observation correlated with the ability of these substrates to stimulate state 3 respiration in the presence of extramitochondrial ATP...
May 16, 2003: Journal of Biological Chemistry
https://read.qxmd.com/read/12531746/creatine-transporter-activity-and-content-in-the-rat-heart-supplemented-by-and-depleted-of-creatine
#32
JOURNAL ARTICLE
Ernest Boehm, Sharon Chan, Mina Monfared, Theo Wallimann, Kieran Clarke, Stefan Neubauer
The intracellular creatine concentration is an important bioenergetic parameter in cardiac muscle. Although creatine uptake is known to be via a NaCl-dependent creatine transporter (CrT), its localization and regulation are poorly understood. We investigated CrT kinetics in isolated perfused hearts and, by using cardiomyocytes, measured CrT content at the plasma membrane or in total lysates. Rats were fed control diet or diet supplemented with creatine or the creatine analog beta-guanidinopropionic acid (beta-GPA)...
February 2003: American Journal of Physiology. Endocrinology and Metabolism
https://read.qxmd.com/read/12444247/amp-kinase-is-required-for-mitochondrial-biogenesis-in-skeletal-muscle-in-response-to-chronic-energy-deprivation
#33
JOURNAL ARTICLE
Haihong Zong, Jian Ming Ren, Lawrence H Young, Marc Pypaert, James Mu, Morris J Birnbaum, Gerald I Shulman
Mitochondrial biogenesis is a critical adaptation to chronic energy deprivation, yet the signaling mechanisms responsible for this response are poorly understood. To examine the role of AMP-activated protein kinase (AMPK), an evolutionarily conserved fuel sensor, in mitochondrial biogenesis we studied transgenic mice expressing a dominant-negative mutant of AMPK in muscle (DN-AMPK). Both DN-AMPK and WT mice were treated with beta-guanidinopropionic acid (GPA), a creatine analog, which led to similar reductions in the intramuscular ATPAMP ratio and phosphocreatine concentrations...
December 10, 2002: Proceedings of the National Academy of Sciences of the United States of America
https://read.qxmd.com/read/12439290/the-blood-brain-barrier-creatine-transporter-is-a-major-pathway-for-supplying-creatine-to-the-brain
#34
JOURNAL ARTICLE
Sumio Ohtsuki, Masanori Tachikawa, Hitomi Takanaga, Hidemi Shimizu, Masahiko Watanabe, Ken-Ichi Hosoya, Tetsuya Terasaki
Although creatine plays a pivotal role in the storage of phosphate-bound energy in the brain, the source of cerebral creatine is still unclear. The authors examined the contribution made by the creatine transporter (CRT) at the blood-brain barrier in supplying creatine to the brain from blood. An intravenous administration study suggested that creatine is continuously transported from the blood to the brain against the creatine concentration gradient that exists between brain and blood. Conditionally immortalized mouse brain capillary endothelial cells (TM-BBB) exhibited creatine uptake, which is Na+ and Cl- dependent and inhibited by CRT inhibitors, such as beta-guanidinopropionate and guanidinoacetate...
November 2002: Journal of Cerebral Blood Flow and Metabolism
https://read.qxmd.com/read/12433955/human-rat-and-chicken-small-intestinal-na-cl-creatine-transporter-functional-molecular-characterization-and-localization
#35
JOURNAL ARTICLE
M J Peral, M García-Delgado, M L Calonge, J M Durán, M C De La Horra, T Wallimann, O Speer, A Ilundáin
In spite of all the fascinating properties of oral creatine supplementation, the mechanism(s) mediating its intestinal absorption has(have) not been investigated. The purpose of this study was to characterize intestinal creatine transport. [(14)C] creatine uptake was measured in chicken enterocytes and rat ileum, and expression of the creatine transporter CRT was examined in human, rat and chicken small intestine by reverse transcription-polymerase chain reaction, Northern blot, in situ hybridization, immunoblotting and immunohistochemistry...
November 15, 2002: Journal of Physiology
https://read.qxmd.com/read/12207567/effects-of-creatine-loading-and-depletion-on-rat-skeletal-muscle-contraction
#36
JOURNAL ARTICLE
M Gagnon, M Maguire, M MacDermott, A Bradford
1. In humans, the effects of dietary creatine supplementation are controversial, with some studies showing increased muscle force and fatigue resistance and others reporting no effect on exercise performance. Little is known about the effects of creatine on muscle contractile properties. 2. Rats were fed a standard diet, creatine for 10 days or beta-guanidinopropionate, which depletes muscle creatine, for 7 days. Contractile properties were measured in isolated extensor digitorum longus and sternohyoid muscle as representative limb and upper airway dilator muscles, respectively...
October 2002: Clinical and Experimental Pharmacology & Physiology
https://read.qxmd.com/read/11976926/dehydration-modifies-guanidino-compound-concentrations-in-the-different-zones-of-the-rat-kidney
#37
JOURNAL ARTICLE
Olivier Levillain, Bart Marescau, Ilse Possemiers, Paul De Deyn
Guanidino compounds (GCs) related to arginine (Arg) are unevenly distributed along the cortico-papillary axis of the rat kidney. Inasmuch as the concentration of alpha-keto-delta-guanidinovaleric acid (alpha-keto-delta-GVA), guanidinosuccinic acid (GSA), creatinine (CTN), gamma-guanidinobutyric acid (gamma-GBA) and methylguanidine (MG) increased steeply along the inner medulla in parallel to the urea and osmotic gradients, the question arose as to whether dehydration enhances their renal content and distribution...
May 2002: Pflügers Archiv: European Journal of Physiology
https://read.qxmd.com/read/11591624/chronic-phosphocreatine-depletion-by-the-creatine-analogue-beta-guanidinopropionate-is-associated-with-increased-mortality-and-loss-of-atp-in-rats-after-myocardial-infarction
#38
JOURNAL ARTICLE
M Horn, H Remkes, H Strömer, C Dienesch, S Neubauer
BACKGROUND: The failing myocardium is characterized by reductions of phosphocreatine (PCr) and free creatine content and by decreases of energy reserve via creatine kinase (CK), ie, CK reaction velocity (Flux(CK)). It has remained unclear whether these changes contribute directly to contractile dysfunction. In the present study, myocardial PCr stores in a heart failure model were further depleted by feeding of the PCr analogue beta-guanidinopropionate (GP). Functional and metabolic consequences were studied...
October 9, 2001: Circulation
https://read.qxmd.com/read/11518774/creatine-transport-in-brush-border-membrane-vesicles-isolated-from-rat-kidney-cortex
#39
JOURNAL ARTICLE
M García-Delgado, M J Peral, M Cano, M L Calonge, A A Ilundáin
The kidney efficiently salvages creatine from the urine; however, the mechanism(s) that mediates renal creatine reabsorption has not been investigated. This study characterizes the creatine transport mechanism in brush-border membrane vesicles isolated from the rat renal cortex. An osmolality plot revealed that creatine is transported into an osmotically active space and that it is also bound to the membranes. An inwardly directed NaCl gradient stimulated creatine uptake and the time course of uptake exhibited an overshoot phenomenon, which indicates the presence of an active process for creatine in these membranes...
September 2001: Journal of the American Society of Nephrology: JASN
https://read.qxmd.com/read/11160061/fiber-type-and-metabolic-dependence-of-t2-increases-in-stimulated-rat-muscles
#40
JOURNAL ARTICLE
B M Prior, L L Ploutz-Snyder, T G Cooper, R A Meyer
This study examined the relationships between muscle fiber type, metabolism, and blood flow vs. the increase in skeletal muscle (1)H-NMR transverse relaxation time (T2) after stimulation. Triceps surae muscles of anesthetized rats were stimulated in situ at 1-10 Hz for 6 min, and T2 was calculated from (1)H-NMR images acquired at 4.7 T immediately after stimulation. At low-to-intermediate frequencies (1-5 Hz), the stimulation-induced T2 increase was greater in the superficial, fast-twitch white portion of the gastrocnemius muscle compared with the deeper, more aerobic muscles of the triceps surae group...
February 2001: Journal of Applied Physiology
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