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Tytuł:
Kinetics of a nucleoside release from lactide-caprolactone and lactide-glycolide polymers in vitro.
Autorzy:
Kryczka, Tomasz
Grieb, Paweł
Bero, Maciej
Kasperczyk, Janusz
Dobrzynski, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/1044392.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
biodegradable polymers
adenosine
Opis:
We assessed the rate of release of a model nucleoside (adenosine, 5%, w/w) from nine different lactide-glycolide or lactide-caprolactone polymers. The polymer discs were eluted every second day with an artificial cerebrospinal fluid at the elution rate roughly approximating the brain extracellular fluid formation rate. Adenosine in eluate samples was assayed by HPLC. Three polymers exhibited a relatively constant release of adenosine for over four weeks, resulting in micromolar concentrations of nucleoside in the eluate. This points to the neccessity of further development of polymers of this types as intracerebral nucleoside delivery systems for local treatment of brain tumors.
Źródło:
Acta Biochimica Polonica; 2000, 47, 1; 59-64
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synteza analogów adenozyny
Synthesis of adenosine analogues
Autorzy:
Samsel, M.
Dzierzbicka, K.
Powiązania:
https://bibliotekanauki.pl/articles/172542.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
adenozyna
receptory dla adenozyny
analogi adenozyny
aktywność biologiczna
adenosine
adenosine receptors
synthesis
adenosine analogues
biological activity
Opis:
Adenosine (Rys. 1) is a purine nucleoside playing an important role in human body. It is involved in key pathways such as purinergic nucleic acid base synthesis, amino acid metabolism and modulation of cellular metabolic status [1,2]. Adenosine acts through the four types of adenosine receptors: A1, A2A, A2B and A3 belonging to the G protein-coupled receptor family [3]. In physiological conditions this nucleoside is present in a micromolar range [5]. However, when metabolic stress occurs extracellular level of adenosine raises revealing its protective properties. Depending on an activated receptor subtype, adenosine demonstrates cardioprotective and neuroprotective activity during hypoxia or ischemia, it stimulates the immunological system [6, 7]. Besides many potential applications, adenosine is used mainly for the treatment of paroxysmal supraventricular tachycardia. Limitations are linked to a very short blood half-time and no receptor specificity [8]. This review is focused on novel literature data about synthesis of adenosine analogues with interesting biological activities. In order to influence adenosine receptor selectivity and pharmacokinetic properties a nucleoside structure can be modified in purine [14, 15, 17, 22, 26, 27, 35] or sugar ring [29, 32]. New interesting compounds are also synthesized by cyclisation of adenosine [36]. Modification of adenosine structure allowed obtaining compounds with targeted action: antiarrhythmic [11, 12], antinociceptive [9], antilipolytic [13], antiviral [29] or anticancer [35].
Źródło:
Wiadomości Chemiczne; 2012, 66, 3-4; 321-340
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of insulin and glucose on adenosine metabolizing enzymes in human B lymphocytes
Autorzy:
Kocbuch, Katarzyna
Sakowicz-Burkiewicz, Monika
Grden, Marzena
Szutowicz, Andrzej
Pawelczyk, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1040536.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
glucose
insulin
B lymphocytes
adenosine kinase
adenosine deaminase
5'-nucleotidase
Opis:
In diabetes several aspects of immunity are altered, including the immunomodulatory action of adenosine. Our study was undertaken to investigate the effect of different glucose and insulin concentrations on activities of adenosine metabolizing enzymes in human B lymphocytes line SKW 6.4. The activity of adenosine deaminase in the cytosolic fraction was very low and was not affected by different glucose concentration, but in the membrane fraction of cells cultured with 25 mM glucose it was decreased by about 35% comparing to the activity in cells maintained in 5 mM glucose, irrespective of insulin concentration. The activities of 5'-nucleotidase (5'-NT) and ecto-5'-NT in SKW 6.4 cells depended on insulin concentration, but not on glucose. Cells cultured with 10-8 M insulin displayed an about 60% lower activity of cytosolic 5'-NT comparing to cells maintained at 10-11 M insulin. The activity of ecto-5'-NT was decreased by about 70% in cells cultured with 10-8 M insulin comparing to cells grown in 10-11 M insulin. Neither insulin nor glucose had an effect on adenosine kinase (AK) activity in SKW 6.4 cells or in human B cells isolated from peripheral blood. The extracellular level of adenosine and inosine during accelerated catabolism of cellular ATP depended on glucose, but not on insulin concentration. Concluding, our study demonstrates that glucose and insulin differentially affect the activities of adenosine metabolizing enzymes in human B lymphocytes, but changes in those activities do not correlate with the adenosine level in cell media during accelerated ATP catabolism, implying that nucleoside transport is the primary factor determining the extracellular level of adenosine.
Źródło:
Acta Biochimica Polonica; 2009, 56, 3; 439-446
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Purinergic signaling in B cells
Autorzy:
Przybyła, Tomasz
Sakowicz-Burkiewicz, Monika
Pawełczyk, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1038516.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
B cells
purinergic signaling
adenosine
adenosine triphosphate
P1 receptors
P2 receptors
Opis:
Adenosine and adenosine triphosphate are involved in purinergic signaling which plays an important role in control of the immune system. Much data have been obtained regarding impact of purinergic signaling on dendritic cells, macrophages, monocytes and T lymphocytes, however less attention has been paid to purinergic regulation of B cells. This review summarizes present knowledge on ATP- and Ado-dependent signaling in B lymphocytes. Human B cells have been shown to express A1-AR, A2A-AR, A2B-AR and A3-AR and each subtype of P2 receptors. Surface of B cells exhibits two antagonistic ectoenzymatic pathways, one relies on constitutive secretion and resynthesis of ATP, while the second one depends on degradation of adenosine nucleotides to nucleosides and their subsequent degradation. Inactivated B cells remain under the suppressive impact of autocrine and paracrine Ado, whereas activated B lymphocytes increase ATP release and production. ATP protects B cells from Ado-induced suppression and exerts pro-inflammatory effect on the target tissues, and it is also involved in the IgM release. On the other hand, Ado synthesis is necessary for optimal development, implantation and maintenance of the plasmocyte population in bone marrow in the course of the primary immune response. Moreover, Ado plays an important role in immunoglobulin class switching, which is a key mechanism of humoral immune response. Disruption of purinergic signaling leads to severe disorders. Impairment of Ado metabolism is one of the factors responsible for common variable immunodeficiency. There are several lines of evidence that dysfunction of the immune system observed during diabetes may in part depend on disrupted ATP and Ado metabolism in the B cells.
Źródło:
Acta Biochimica Polonica; 2018, 65, 1; 1-7
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adenosine as a metabolic regulator of tissue function: production of adenosine by cytoplasmic 5-nucleotidases
Autorzy:
Borowiec, Agnieszka
Lechward, Katarzyna
Tkacz-Stachowska, Kinga
Składanowski, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1041236.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
5'-nucleotidase
adenosine
metabolic regulation
Opis:
Adenosine is a product of complete dephosphorylation of adenine nucleotides which takes place in various compartments of the cell. This nucleoside is a significant signal molecule engaged in regulation of physiology and modulation of the function of numerous cell types (i.e. neurons, platelets, neutrophils, mast cells and smooth muscle cells in bronchi and vasculature, myocytes etc.). As part a of purinergic signaling system, adenosine mediates neurotransmission, conduction, secretion, vasodilation, proliferation and cell death. Most of the effects of adenosine help to protect cells and tissues during stress conditions such as ischemia or anoxia. Adenosine receptors and nucleoside transporters are targets for potential drugs in many pathophysiological situations. The adenosine-producing system in vertebrates involves a cascade dephosphorylating ATP and ending with 5'-nucleotidase (EC 3.1.3.5) localized either on the membrane or inside the cell. In this paper the cytoplasmic variants of 5'-nucleotidase are broadly characterized as well as their clinical relevance. The role of AMP-selective 5'-nucleotidase (cN-I) in the heart, skeletal muscle and brain is highlighted. cN-I action is crucial during ischemia and important for the efficacy of some nucleoside-based drugs and in the regulation of the substrate pool for nucleic acids synthesis. Inhibitors used in studying the roles of cytoplasmic and membrane-bound 5'-nucleotidases are also described.
Źródło:
Acta Biochimica Polonica; 2006, 53, 2; 269-278
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inhibition study of adenosine deaminase by caffeine using spectroscopy and isothermal titration calorimetry.
Autorzy:
Saboury, A
Divsalar, A
Ataie, G
Amanlou, M
Moosavi-Movahedi, A
Hakimelahi, G
Powiązania:
https://bibliotekanauki.pl/articles/1043464.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
calorimetry
inhibition
caffeine
adenosine deaminase
Opis:
Kinetic and thermodynamic studies were made on the effect of caffeine on the activity of adenosine deaminase in 50 mM sodium phosphate buffer, pH 7.5, using UV spectrophotometry and isothermal titration calorimetry (ITC). An uncompetitive inhibition was observed for caffeine. A graphical fitting method was used for determination of binding constant and enthalpy of inhibitor binding by using isothermal titration microcalorimetry data. The dissociation-binding constant is equal to 350 μM by the microcalorimetry method, which agrees well with the value of 342 μM for the inhibition constant that was obtained from the spectroscopy method. Positive dependence of caffeine binding on temperature indicates a hydrophobic interaction.
Źródło:
Acta Biochimica Polonica; 2003, 50, 3; 849-855
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Czy pochodne nukleozydów i nukleotydów mogą w przyszłości stać się skutecznymi lekami przeciwpadaczkowymi?
Can nucleoside and nucleotide precursors become future successful anti-epileptic drugs?
Autorzy:
Cieślak, Marek
Komoszyński, Michał
Powiązania:
https://bibliotekanauki.pl/articles/1058218.pdf
Data publikacji:
2010
Wydawca:
Medical Communications
Tematy:
adenosine
adenosine receptors
epileptic seizure
guanosine
neuroprotection
napad drgawkowy
neuroprotekcja
adenozyna
guanozyna
receptory adenozynowe
Opis:
Many examples of experimental epilepsy show that epileptic seizures occur due to release of stimulatory neurotransmitters into intracellular spaces. In CNS adenosine suppresses exocytosis of glutamate and asparginate but guanosine increases the reverse uptake of glutamate by astrocytes and thus lowers it concentration outside the cell. In this process both nucleosides participate in suppressing the epileptic seizures. By decreasing concentration of ectoadenosine and ectoguanosine outside the cell, that compounds can protect neurons from cellular degeneration. It was shown in many animal models for experimental epilepsy that adenosine A1 and A2A receptors were involved in the process of stopping the seizures. Moreover, some of the conventional anti-epileptic drugs reveal enhance their therapeutic abilities by interactions with the adenosine receptors, being either agonists or antagonists. These interactions modulate the activity of receptors and consequently regulate the neuroprotection processes. Some agonists of adenosine receptors increase the epileptic episodes reaction to those compounds. Anti-episode action of adenosine and guanosine as well as agonists and antagonists of nucleoside receptors indicate the possibility of applying the knowledge about these processes towards production of new anti-epileptic medication. Successful anti-epileptic medication may be based on compounds that have the ability to increase the concentration of ectoadenosine i.e; adenosine deaminase inhibitors, adenosine kinase inhibitors or compounds with ability to suppress reverse uptake of nucleosides. Another method to increase the concentration of extracellular adenosine is to increase the activity of 5’-nucleotidase. That in effect will increase the amount of ectoadenosine by degradation of ectoAMP. There are very promising results revealed that oral administration of guanosine and GMP as well as guanosine by itself given intraperitoneally and intraventricularly what halted epileptic seizures caused by quinolinic acid which is a glutamate agonist.
Napady drgawkowe są wynikiem uwalniania neurotransmiterów pobudzających do przestrzeni pozakomórkowej. W ośrodkowym układzie nerwowym ektoadenozyna hamuje egzocytozę glutaminianu i asparaginianu, natomiast ektoguanozyna, zwiększając wychwyt zwrotny glutaminianu przez astrocyty, obniża jego stężenie poza komórką. W ten sposób oba nukleozydy uczestniczą w hamowaniu napadu drgawkowego. Nukleozydy te, obniżając stężenie powyższych neurotransmiterów poza komórką, chronią neurony przed śmiercią, pełnią więc funkcję neuroprotekcyjną. W różnych modelach zwierzęcych padaczek eksperymentalnych wykazano, że w przerwaniu napadu drgawkowego uczestniczą receptory adenozynowe A1 i A2A. Ma miejsce współdziałanie leków przeciwpadaczkowych i receptorów adenozynowych, bowiem niektóre z nich, takie jak karbamazepina, działają za pośrednictwem receptorów adenozynowych A1, a niektórzy agoniści receptorów A1 potęgują działanie przeciwdrgawkowe tych leków. Przeciwdrgawkowe działanie adenozyny i guanozyny oraz agonistów i antagonistów receptorów nukleozydowych wskazuje na możliwość wykorzystania wiedzy o tych procesach w projektowaniu nowych leków przeciwpadaczkowych. Skutecznymi lekami przeciwdrgawkowymi mogą okazać się związki zwiększające stężenie ektoadenozyny, takie jak: inhibitory deaminazy adenozyny, kinazy adenozynowej oraz związki hamujące wychwyt zwrotny nukleozydów. Innym sposobem zwiększenia stężenia pozakomórkowej adenozyny jest wzrost aktywności 5’-nukleotydazy powiększającej pulę ektoadenozyny przez degradację ektoAMP. Obiecujące są również rezultaty doustnego podania guanozyny i GMP, a także samej guanozyny podanej dokomorowo i dootrzewnowo, które powodowało przerywanie drgawek wywoływanych przez agonistę glutaminianu – kwas chinolinowy.
Źródło:
Aktualności Neurologiczne; 2010, 10, 4; 206-212
1641-9227
2451-0696
Pojawia się w:
Aktualności Neurologiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Czy pochodne nukleozydów i nukleotydów mogą w przyszłości stać się skutecznymi lekami przeciwpadaczkowymi?
Can nucleoside and nucleotide precursors become future successful anti-epileptic drugs?
Autorzy:
Ciślak, Marek
Komoszyński, Michał
Powiązania:
https://bibliotekanauki.pl/articles/1061366.pdf
Data publikacji:
2006
Wydawca:
Medical Communications
Tematy:
adenosine
adenosine receptors
epileptic seizure
guanosine
neuroprotection
neuroprotekcja
receptory adenozynowe
adenozyna
guanozyna
napad drgawkowy
Opis:
Many examples of experimental epilepsy show that epileptic seizures occur due to release of stimulatory neurotransmitters into intracellular spaces. In CNS adenosine suppresses exocytosis of glutamate and asparginate but guanosine increases the reverse uptake of glutamate by astrocytes and thus lowers it concentration outside the cell. In this process both nucleosides participate in suppressing the epileptic seizures. By decreasing concentration of ectoadenosine and ectoguanosine outside the cell, that compounds can protect neurons from cellular degeneration. It was shown in many animal models for experimental epilepsy that adenosine A1 and A2A receptors were involved in the process of stopping the seizures. Moreover, some of the conventional anti-epileptic drugs reveal enhance their therapeutic abilities by interactions with the adenosine receptors, being either agonists or antagonists. These interactions modulate the activity of receptors and consequently regulate the neuroprotection processes. Some agonists of adenosine receptors increase the epileptic episodes reaction to those compounds. Anti-episode action of adenosine and guanosine as well as agonists and antagonists of nucleoside receptors indicate the possibility of applying the knowledge about these processes towards production of new anti-epileptic medication. Successful anti-epileptic medication may be based on compounds that have the ability to increase the concentration of ectoadenosine i.e. adenosine deaminase inhibitors, adenosine kinase inhibitors or compounds with ability to suppress reverse uptake of nucleosides. Another method to increase the concentration of extracellular adenosine is to increase the activity of 5’-nucleotidase. That in effect will increase the amount of ectoadenosine by degradation of ecto-AMP. There are very promising results revealed that oral administration of guanosine and GMP as well as guanosine by itself given intraperitoneally and intraventricularly what halted epileptic seizures caused by quinolinic acid which is a glutamate agonist.
Napady drgawkowe są wynikiem uwalniania neurotransmiterów pobudzających do przestrzeni pozakomórkowej. W ośrodkowym układzie nerwowym ektoadenozyna hamuje egzocytozę glutaminianu i asparaginianu, natomiast ektoguanozyna, zwiększając wychwyt zwrotny glutaminianu przez astrocyty, obniża jego stężenie poza komórką. W ten sposób oba nukleozydy uczestniczą w hamowaniu napadu drgawkowego. Nukleozydy te, obniżając stężenie powyższych neurotransmiterów poza komórką, chronią neurony przed śmiercią, pełnią więc funkcję neuroprotekcyjną. W różnych modelach zwierzęcych padaczek eksperymentalnych wykazano, że w przerwaniu napadu drgawkowego uczestniczą receptory adenozynowe A1 i A2A. Ma miejsce współdziałanie leków przeciwpadaczkowych i receptorów adenozynowych, bowiem niektóre z nich, takie jak karbamazepina, działają za pośrednictwem receptorów adenozynowych A1, a niektórzy agoniści receptorów A1 potęgują działanie przeciwdrgawkowe tych leków. Przeciwdrgawkowe działanie adenozyny i guanozyny oraz agonistów i antagonistów receptorów nukleozydowych wskazuje na możliwość wykorzystania wiedzy o tych procesach w projektowaniu nowych leków przeciwpadaczkowych. Skutecznymi lekami przeciwdrgawkowymi mogą okazać się związki zwiększające stężenie ektoadenozyny, takie jak: inhibitory deaminazy adenozyny, kinazy adenozynowej oraz związki hamujące wychwyt zwrotny nukleozydów. Innym sposobem zwiększenia stężenia pozakomórkowej adenozyny jest wzrost aktywności 5’-nukleotydazy powiększającej pulę ektoadenozyny przez degradację ektoAMP. Obiecujące są również rezultaty doustnego podania guanozyny i GMP, a także samej guanozyny podanej dokomorowo i dootrzewnowo, które powodowało przerywanie drgawek wywoływanych przez agonistę glutaminianu – kwas chinolinowy.
Źródło:
Aktualności Neurologiczne; 2006, 6, 2; 124-130
1641-9227
2451-0696
Pojawia się w:
Aktualności Neurologiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A biochemical study on the level of lipids and glycoproteins in the serum and platelets of liver cirrhotic bleeders
Autorzy:
Vijayalakshmi, Sivagurunathan
Geetha, Arumugam
Jeyachristy, Sam
Powiązania:
https://bibliotekanauki.pl/articles/1041294.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
glycoproteins
lipids
cirrhosis
adenosine triphosphatases
platelets
Opis:
Bleeding complication and abnormal platelet functions are associated with liver cirrhosis. The aim of the present investigation was to assess the functional integrity of platelets in terms of lipids like cholesterol and phospholipids, glycoproteins and membrane-bound enzymes. Liver cirrhotic patients with bleeding complications were studied. Age and sex matched normal healthy volunteers were also involved in this study as a control group. Levels of cholesterol, phospholipids, glycoproteins and adenosine triphosphatases were assessed in isolated platelet membrane fraction. The level of glycoproteins and the activity of adenosine triphosphatases were found to be decreased significantly in cirrhotic patients. The cholesterol/phospholipid ratio was found to be altered significantly, indicating an alteration in the fluidity of platelet membrane. The results of this study reveal that the functional impairment of platelets in liver cirrhotic patients which is responsible for their bleeding tendency might also be due to altered lipid and enzyme levels in platelet membrane.
Źródło:
Acta Biochimica Polonica; 2006, 53, 1; 213-220
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Caffeine and neurodegenerative disorders
Autorzy:
BOGATKO, Karolina
SZOPA, Aleksandra
POLESZAK, Ewa
Powiązania:
https://bibliotekanauki.pl/articles/1033776.pdf
Data publikacji:
2014
Wydawca:
Zakład Opieki Zdrowotnej Ośrodek Umea Shinoda-Kuracejo
Tematy:
Alzheimer’s disease
Parkinson’s disease
adenosine
caffeine
Opis:
Neurodegenerative disorders are amongst the most dangerous diseases in modern society. At the end of 1990, adenosine receptor antagonists were used to block the adenosine A1 and A2A receptors causing less physical, cellular and molecular damage caused by Alzheimer’s and Parkinson’s diseases. In recent years, an increase in death rate caused by these diseases has been observed among people under 74. Caffeine, as NMDA receptor antagonist, prevents an uncontrolled influx of calcium ions into the interior of the cells exerting a neuroprotective effect and beneficial procognitive effects. There is much evidence that caffeine intake is associated with a reduced risk of Alzheimer’s and Parkinson’s diseases.
Źródło:
Medicina Internacia Revuo; 2014, 26, 103; 89-93
0465-5435
Pojawia się w:
Medicina Internacia Revuo
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Expression level of adenosine kinase in rat tissues. Lack of phosphate effect on the enzyme activity.
Autorzy:
Sakowicz, Monika
Grdeń, Marzena
Pawełczyk, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1044105.pdf
Data publikacji:
2001
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
rat
recombinant protein
phosphate
tissue distribution
adenosine kinase
Opis:
In this report we describe cloning and expression of rat adenosine kinase (AK) in Esccherichaia coli cells as a fusion protein with 6xHis. The recombinant protein was purified and polyclonal antibodies to AK were generated in rabbits. Immunoblot analysis of extracts obtained from various rat tissues revealed two protein bands reactive with anti-AK IgG. The apparent molecular mass of these bands was 48 and 38 kDa in rat kidney, liver, spleen, brain, and lung. In heart and muscle the proteins that react with AK antibodies have the molecular masses of 48 and 40.5 kDa. In order to assess the relative AK mRNA level in rat tissues we used the multiplex PCR technique with β-actin mRNA as a reference. We found the highest level of AK mRNA in the liver, which decreased in the order kidney >spleen >lung >heart >brain >muscle. Measurement of AK activity in cytosolic fractions of rat tissues showed the highest activity in the liver (0.58 U/g), which decreased in the order kidney >spleen >lung >brain >heart >skeletal muscle. Kinetic studies on recombinant AK as well as on AK in the cytosolic fraction of various rat tissues showed that this enzyme is not affected by phosphate ions. The data presented indicate that in the rat tissues investigated at least two isoforms of adenosine kinase are expressed, and that the expression of the AK gene appears to have some degree of tissue specificity.
Źródło:
Acta Biochimica Polonica; 2001, 48, 3; 745-754
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Purinergic signaling in the pancreas and the therapeutic potential of ecto-nucleotidases in diabetes
Autorzy:
Cieślak, Marek
Roszek, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/1039191.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
ATP
adenosine
pancreas
diabetes mellitus
P-type receptors
ecto-nucleotidases
Opis:
It is widely accepted that purinergic signaling is involved in the regulation of functions of all known tissues and organs. Extracellular purines activate two classes of receptors, P1-adenosine receptors and P2-nucleotide receptors, in a concentration-dependent manner. Ecto-enzymes metabolizing nucleotides outside the cell are involved in the termination of the nucleotide signaling pathway through the release of ligands from their receptors. The pancreas is a central organ in nutrient and energy homeostasis with endocrine, exocrine and immunoreactive functions. The disturbances in cellular metabolism in diabetes mellitus lead also to changes in concentrations of intra- and extracellular nucleotides. Purinergic receptors P1 and P2 are present on the pancreatic islet cells as well as on hepatocytes, adipocytes, pancreatic blood vessels and nerves. The ATP-dependent P2X receptor activation on pancreatic β-cells results in a positive autocrine signal and subsequent insulin secretion. Ecto-NTPDases play the key role in regulation of extracellular ATP concentration. These enzymes, in cooperation with 5'-nucleotidase can significantly increase ecto-adenosine concentration. It has been demonstrated that adenosine, through activation of P1 receptors present on adipocytes and pancreatic islets cells, inhibits the release of insulin. Even though we know for 50 years about the regulatory role of nucleotides in the secretion of insulin, an integrated understanding of the involvement of purinergic signaling in pancreas function is still required. This comprehensive review presents our current knowledge about purinergic signaling in physiology and pathology of the pancreas as well as its potential therapeutic relevance in diabetes.
Źródło:
Acta Biochimica Polonica; 2014, 61, 4; 655-662
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent advances in studies on biochemical and structural properties of equilibrative and concentrative nucleoside transporters
Autorzy:
Podgorska, Marzena
Kocbuch, Katarzyna
Pawelczyk, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1041310.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
nucleoside transporters
structure
gene locus
substrate specificity
tissue distribution
adenosine
Opis:
Nucleoside transporters (NT) facilitate the movement of nucleosides and nucleobases across cell membranes. NT-mediated transport is vital for the synthesis of nucleic acids in cells that lack de novo purine synthesis. Some nucleosides display biological activity and act as signalling molecules. For example, adenosine exerts a potent action on many physiological processes including vasodilatation, hormone and neurotransmitter release, platelet aggregation, and lipolysis. Therefore, carrier-mediated transport of this nucleoside plays an important role in modulating cell function, because the efficiency of the transport processes determines adenosine availability to its receptors or to metabolizing enzymes. Nucleoside transporters are also key elements in anticancer and antiviral therapy with the use of nucleoside analogues. Mammalian cells possess two major nucleoside transporter families: equilibrative (ENT) and concentrative (CNT) Na+-dependent ones. This review characterizes gene loci, substrate specificity, tissue distribution, membrane topology and structure of ENT and CNT proteins. Regulation of nucleoside transporters by various factors is also presented.
Źródło:
Acta Biochimica Polonica; 2005, 52, 4; 749-758
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Role of Adenosine A2a Receptors in Antidepressant Activity in An Experimental Animal Model of Depression
Autorzy:
DZIUBINA, Anna
ZYGMUNT, Małgorzata
FILIPEK, Barbara
SAŁAT, Kinga
BRYŁA, Adrian
LIBROWSKI, Tadeusz
GDULA-ARGASIŃSKA, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/1033607.pdf
Data publikacji:
2017
Wydawca:
Zakład Opieki Zdrowotnej Ośrodek Umea Shinoda-Kuracejo
Tematy:
A2A receptor
Parkinson’s disease
adenosine
antidepressant activity
depression
Opis:
Intensive studies on the role of adenosine A2A receptors in Parkinson’s disease have been carried out for many years,. These studies have indicated that the antagonists of these receptors not only alleviate motor deficits but also exhibit neuroprotective effects in various animal models. Little is known about the role of these receptors in ailments accompanying Parkinson’s disease, such as depression and anxiety. This paper provides a summary of existing research on the role of A2A receptors in comorbid depression in Parkinson’s disease.
Źródło:
Medicina Internacia Revuo; 2017, 28, 109; 228-236
0465-5435
Pojawia się w:
Medicina Internacia Revuo
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elevation of the adenylate pool in rat cardiomyocytes by S-adenosyl-L-methionine.
Autorzy:
Smolenski, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/1044271.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
cardiomyocytes
ribose
adenylate pool
ATP
adenine
S-adenosyl-L-methionine
adenosine
Opis:
Rapid resynthesis of the adenylate pool in cardiac myocytes is important for recovery of contractility and normal function of regulatory mechanisms in the heart. Adenosine and adenine are thought to be the most effective substrates for nucleotide synthesis, but the possibility of using other compounds has been studied very little in cardiomyocytes. In the present study, the effect of S-adenosyl-L-methionine (SAM) on the adenylate pool of isolated cardiomyocytes was investigated and compared to the effect of adenine and adenosine. Adult rat cardiomyocytes were isolated using the collagenase perfusion technique. The cells were incubated in the presence of adenine derivatives for 90 min followed by nucleotide determination by HPLC. The concentrations of adenine nucleotides expressed in nmol/mg of cell protein were initially 22.1 ± 1.4, 4.0 ± 0.3 and 0.70 ± 0.08 for ATP, ADP and AMP, respectively (n = 10, ±S.E.M.), and the total adenylate pool was 26.8 ± 1.6. In the presence of 1.25 mM SAM in the medium, the adenylate pool increased by 5.2 ± 0.4 nmol/mg of cell protein, but only if 1 mM ribose was additionally present in the medium. No changes were observed with SAM alone. A similar increase (by 4.9 ± 0.6 nmol/mg protein) was observed after incubation with 1.25 mM adenine plus 1 mM ribose, but no increase was observed if ribose was omitted. Adenosine at 0.1 or 1.25 mM concentrations also caused an increase in the adenylate pool (by 5.2 ± 1.0 and 5.2 ± 0.9 nmol/mg protein, respectively), which in contrast to the SAM or adenine was independent of the additional presence of ribose. Thus, S-adenosyl-L-methionine could be used as a precursor of the adenylate pool in cardiomyocytes, which is as efficient in increasing the adenylate pool after 90 min of incubation as adenosine or adenine. Nucleotide synthesis from SAM involves the formation of adenine as an intermediate with its subsequent incorporation by adenine phosphoribosyltransferase.
Źródło:
Acta Biochimica Polonica; 2000, 47, 4; 1171-1178
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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