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1.

001-es BibID:BIBFORM006034
Első szerző:Gáspár Rezső (biofizikus)
Cím:Bretylium-induced voltage-gated sodium current in human lymphocytes / Rezső Gáspár, Zoltán Krasznai, Teréz Márián, Lajos Trón, Rina Recchioni, Marco Falasca, Fausto Moroni, Carlo Pieri, Sándor Damjanovich
Dátum:1992
ISSN:0167-4889
Megjegyzések:Using the whole-cell variation of the patch-clamp technique it has been determined that 0.25-3 mM bretylium tosylate (BT) exerts a repolarizing effect on partially depolarized human lymphocytes. The repolarizing effect was ouabain (40 microM)-sensitive, and was inhibited by the removal of external Na+ or by the Na(+)-channel-blocker amiloride (10-44 microM), but K(+)-channel-blockers 4-aminopyridine (0.1-5 mM) and quinine (100 microM) had no effect. The drug induced a sodium dependent, amiloride-sensitive transient inward current reaching its maximum value approx. 20-30 s after the administration of BT and lasting for 6-10 min. This current was activated by depolarization within 25 ms at around -42 mV, its inactivation took about 2 s and its reversal potential was +24 +/- 5 mV. An increase in the intracellular sodium concentration (1.8-3.2 mM) has been observed upon the addition of BT by monitoring the SBFI fluorescence of the dye-loaded cells. It has been shown that whole-cell K+ currents are significantly decreased by BT. The existence of voltage and ligand (BT)-gated sodium channels has been postulated in human lymphocytes. These channels are thought to participate in the initiation of membrane repolarization in human lymphocytes, and thereby influence mitogenic or antigen-induced cell-activation processes.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Bretylium
Ion channel
Patch-clamp
Human lymphocyte
Megjelenés:Biochimica et Biophysica Acta (BBA). Molecular Cell Research. - 1137 : 2 (1992), p. 143-147. -
További szerzők:Krasznai Zoltán (1950-) (biofizikus) Márián Teréz (1950-) (radiobiológus) Trón Lajos (1941-) (biofizikus) Recchioni, Rina Falasca, Marco Moroni, Fausto Pieri, Carlo Damjanovich Sándor (1936-2017) (biofizikus)
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DOI
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2.

001-es BibID:BIBFORM040003
Első szerző:Krasznai Zoltán (biofizikus)
Cím:A slow outward current and a hypoosmolality induced anion conductance in embryonic chicken osteoclasts / Krasznai, Z., Weidema, F., Ypey, D. L., Damjanovich, S., Gaspar, R., Marian, T.
Dátum:2001
ISSN:0236-5383
Megjegyzések:In this paper we report on a hypoosmolality induced current, I(osmo), in embryonic chicken osteoclasts, which could only be studied when blocking a simultaneously active, unidentified slow outward current, I(slo). I(slo) was observed in all of the examined cells when both the intracellular and extracellular solutions contained sodium as the major cation and no potassium. The current was outwardly rectifying and activated at membrane potentials more positive than -44 +/- 12 mV (n = 31). The time to half activation of the current was also voltage dependent and was 350 ms at Vm = +80 mV, and 78 ms at Vm = +120 mV. The current did not inactivate during periods up to 5 s. Extracellular 4-AP (5 mM), TEA (5 mM) and Ba2+ (1 mM), blockers of K+ conductances in chicken osteoclasts, did not influence I(slo). However, I(slo) was inhibited by 50 microM extracellular verapamil, which allowed us to study I(osmo) in isolation. Exposure of the osteoclasts to hypotonic solution resulted in the development of a depolarization activated I(osmo). It developed after a 1-min delay and reached its maximum within 10 minutes. Half-maximal activation occurred after 4.4 +/- 0.9 min (n = 9). The current activated within a few ms upon depolarization and did not inactivate during at least 5 sec. I(osmo) reversed around the calculated Nernst potential for Cl- (E(Cl) = +7.3 mV and V(rev) = +5.4 +/- 3.6 mV, n = 9). The underlying conductance, G(osmo) exhibited moderate outward rectification around 0 mV in symmetrical Cl- solutions. Ion substitution experiments showed that G(osmo) is an anion conductance with P(Cl) approximately = P(F) > P(gluc) >> P(Na). I(osmo) was blocked by 0.5 mM SITS but 50 microM verapamil, 5 mM TEA, 5 mM 4-AP, 1 mM Ba2+, 50 microM cytochalasin D and 0.5 mM alendronate did not have any effect on the current. Cl- currents have been implicated in charge neutralization during osteoclastic acid secretion for bone resorption. The present results imply that osmolality may be a factor controlling this charge neutralization.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény hazai lapban
Animal
Anions
Calcium
Calcium Channel Blockers
Chick Embryo
Cytochalasin D
drug effects
Hungary
Ion Transport
Membrane Potentials
metabolism
Osmolar Concentration
Osteoclasts
pharmacology
physiology
Potassium
Sodium
Support,Non-U.S.Gov't
Verapamil
Megjelenés:Acta Biologica Hungarica. - 52 : 1 (2001), p. 47-61. -
További szerzők:Weidema, F. Ypey, Dirk L. Gáspár Rezső (1944-) (biofizikus) Márián Teréz (1950-) (radiobiológus) Damjanovich Sándor (1936-2017) (biofizikus)
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DOI
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3.

001-es BibID:BIBFORM004731
Első szerző:Krasznai Zoltán (biofizikus)
Cím:Role of ion channels and membrane potential in the initiation of carp sperm motility / Krasznai, Z., Morisawa, M., Morisawa, S., Krasznai, Z. T., Tron, L., Gaspar, R., Marian, T.
Dátum:2003
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Ion Channels
Sperm Motility
Megjelenés:Aquatic living resources [electronic resource]. - 16 : 5 (2003), p. 445-449. -
További szerzők:Morisawa, Masaaki Morisawa, Sachiko Krasznai Zoárd Tibor (1973-) (szülész-nőgyógyász, gyermeknőgyógyász) Trón Lajos (1941-) (biofizikus) Gáspár Rezső (1944-) (biofizikus) Márián Teréz (1950-) (radiobiológus)
Internet cím:DOI
elektronikus változat
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4.

001-es BibID:BIBFORM039513
Első szerző:Márián Teréz (radiobiológus)
Cím:A1 and A2 adenosine receptor activation inversely modulates potassium currents and membrane potential in DDT1 MF-2 smooth muscle cells / Marian, T., Rubovszky, B., Szentmiklosi, A. J., Tron, L., Balkay, L., Boros, I., Gaspar, R., Szekely, A., Krasznai, Z.
Dátum:2002
ISSN:0021-5198
Megjegyzések:Adenosine receptors are widely distributed in mammalian tissues and have been possibly involved through transmembrane potential changes in cell function regulation. The effect of A1 and A2A adenosine receptor ligands on transmembrane potential measured with flow cytometry and potassium conductance measured by the patch-clamp technique was investigated in DDT1 MF-2 smooth muscle cells. The A1 adenosine-receptor agonist CPA (50 nM) and the A2A adenosine-receptor agonist CGS 21680 (50 nM) elicited a rapid and maintained increase and decrease in the potassium conductance, respectively, and a concomitant hyperpolarization and depolarization of the membrane, respectively. These effects were eliminated by subtype-selective adenosine receptor antagonists (DPCPX, CSC, ZM 241385, all 1 microM). The ligand induced membrane potential changes were reversible. Based on these detected membrane potential changes along with the published voltage dependence of the adenylyl cyclase, the regulation of cAMP production by A1- and A2A-receptor activation is suggested to be mediated through the induced early hyperpolarization and depolarization. The interaction between the effects of these receptor subtypes allows for a complex regulation mechanism.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:The Japanese Journal of Pharmacology. - 89 : 4 (2002), p. 366-372. -
További szerzők:Rubovszky Bálint (1975-) (élettanász) Szentmiklósi József András (1948-) (farmakológus, klinikai laboratóriumi szakorvos) Trón Lajos (1941-) (biofizikus) Balkay László (1963-) (biofizikus) Boros István Gáspár Rezső (1944-) (biofizikus) Székely Andrea Krasznai Zoltán (1950-) (biofizikus)
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DOI
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5.

001-es BibID:BIBFORM046089
Első szerző:Rubovszky Bálint (élettanász)
Cím:Comparative pharmacological studies on the A2 adenosine receptor agonist 5'-n-ethyl-carboxamidoadenosine and its F19 isotope labelled derivative / Rubovszky B., Szentmiklosi A. J., Marian T., Cseppento A., Gesztelyi R., Szekely A., Forizs F., Gaspar R., Tron L., Krasznai Z.
Dátum:2003
ISSN:1347-8613
Megjegyzések:Adenosine receptors are expressed in various mammalian tissues where they mediate the effects of adenosine on cellular functions through a number of signalling mechanisms. 18F-NECA is the positron-emitting derivative of the A(2)-receptor agonist NECA (5'-n-ethyl-carboxamidoadenosine) and is a radioligand for PET imaging of adenosine receptors. Contractility and relaxation studies were performed on guinea pig atrial myocardium, pulmonary artery, and thoracic aorta to compare the pharmacological effects of NECA and F-NECA (a non-emitting derivative) on tissues. Furthermore, the effect of NECA and F-NECA on the potassium conductance was investigated in DDT1 MF-2 smooth muscle cells with the patch-clamp technique. Both NECA and F-NECA reduced the contractile force in atrial myocardium and evoked phasic contraction in pulmonary artery (A(1) adenosine-receptor-mediated actions) in a dose dependent manner; however, the apparent affinity was lower for F-NECA. No difference was found in relaxation induced by these compounds in 1 microM noradrenaline-precontracted aorta and pulmonary artery (in the presence of DPCPX, an A(1) adenosine receptor antagonist, tissue containing A(2B) adenosine receptors). NECA (5 microM) and F-NECA (5 microM) also decreased the peak current and accelerated activation and inactivation properties of the potassium channels, but F-NECA was less effective. These results suggest that while NECA and F-NECA are equivalent agonists of vascular A(2B) receptors, they mediate different changes of some parameters. When evaluating the data obtained by the use of radiolabelled ligands, one has to take into consideration the possible physiological effects of the ligands besides its binding properties to tissues.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Journal of Pharmacological Sciences. - 93 : 3 (2003), p. 356-363. -
További szerzők:Szentmiklósi József András (1948-) (farmakológus, klinikai laboratóriumi szakorvos) Márián Teréz (1950-) (radiobiológus) Cseppentő Ágnes (1953-) (orvos) Gesztelyi Rudolf (1969-) (kísérletes farmakológus) Székely Andrea Forizs Fruzsina Gáspár Rezső (1944-) (biofizikus) Trón Lajos (1941-) (biofizikus) Krasznai Zoltán (1950-) (biofizikus)
Pályázati támogatás:T 043087
OTKA
T 038270
OTKA
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6.

001-es BibID:BIBFORM002766
Első szerző:Székely Andrea
Cím:Nutrition and immune system : certain fatty acids differently modify membrane composition and consequently kinetics of KV1.3 channels of human peripheral lymphocytes/ Szekely A., Kitajka K., Panyi G., Marian T., Gaspar R., Krasznai Z.
Dátum:2007
Megjegyzések:Potassium (K(+)) channels of human peripheral lymphocytes play a considerable role in the signalling processes required for immune responses. Modification of the fatty acid composition of the membrane influences the functions of various membrane enzymes and ion channels. We set out to establish how the incorporation of fatty acids with different carbon chain lengths and degrees of unsaturation into the cell membrane influences the function of K(V)1.3 channels of lymphocytes, thereby potentially modifying the immune responses of the cells. The incorporation of the fatty acids into the cell membrane was monitored by gas chromatography. Whole-cell patch-clamp experiments demonstrated that the polyunsaturated linoleic acid, arachidonic acid and docosahexaenoic acid all decreased the activation and inactivation time constants of the K(V)1.3 channels, but did not affect the voltage-dependence of steady-state activation and steady-state inactivation of the channels. Treatment with the saturated palmitic acid, stearic acid and the monounsaturated oleic acid did not result in significant changes in the biophysical parameters of K(V)1.3 gating studied. We conclude that the incorporation of fatty acids unsaturated to different degrees into the cell membrane of lymphocytes influenced the rate of gating transitions but not the equilibrium distribution of the channels between different states. This effect depended on the degree of unsaturation and the chain length of the fatty acids: no effects of saturated and monounsaturated fatty acids (16:0, 18:0 and 18:1) were observed whereas treatment with polyunsaturated fatty acids (18:2, 20:4 and 22:6) resulted in significant changes in the channel kinetics
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Biophysics
Cell Membrane
Cells
chemistry
Chromatography
Dietary Fats
Enzymes
Fatty Acids
Human
Humans
Hungary
Immune System
immunology
Ion Channels
Kinetics
Kv1.3 Potassium Channel
Lymphocyte Subsets
Lymphocytes
metabolism
pharmacology
physiology
Potassium
Research
Support
Megjelenés:Immunobiology. - 212 : 3 (2007), p. 213-227. -
További szerzők:Kitajka Klára Panyi György (1966-) (biofizikus) Márián Teréz (1950-) (radiobiológus) Gáspár Rezső (1944-) (biofizikus) Krasznai Zoltán (1950-) (biofizikus)
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