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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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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
Intézményi repozitóriumban (DEA) tárolt változat
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3.

001-es BibID:BIBFORM038939
Első szerző:Krasznai Zoltán (biofizikus)
Cím:Membrane hyperpolarization removes inactivation of Ca2+ channels, leading to Ca2+ influx and subsequent initiation of sperm motility in the common carp / Krasznai, Z., Marian, T., Izumi, H., Damjanovich, S., Balkay, L., Tron, L., Morisawa, M.
Dátum:2000
Megjegyzések:Change of osmolality surrounding spawned sperm from isotonic to hypotonic causes the initiation of sperm motility in the common carp. Here we show that membrane-permeable cAMP does not initiate motility of carp sperm that is quiescent in isotonic solution, and that motility of the demembranated sperm can be reactivated without cAMP. Furthermore, the cAMP level does not change during the initiation of sperm motility, and inhibitors of protein kinase do not affect sperm motility, suggesting that no cAMP-dependent system is necessary for the regulation of sperm motility. Sperm motility could not be initiated in Ca(2+)-free hypoosmotic solutions, and significant increase in the intracellular Ca(2+) level was observed by a Ca-sensitive fluorescence dye during hypoosmolality-induced active motion period. The demembranated sperm cells were fully reactivated in the solutions containing 10(-7) to 10(-5) M Ca(2+). Ca(2+) channel blockers such as verapamil and omega-conotoxin reversibly inhibited the initiation of sperm motility, suggesting that Ca(2+) influx is the prerequisite for the initiation of carp sperm motility. Motility of intact sperm was completely blocked; however, that of the demembranated sperm was not inhibited by the calmodulin inhibitor W7, suggesting that the calmodulin bound close to the plasma membrane participated in the initiation of sperm motility. Flow cytometric membrane potential measurements and spectrophotometric measurements by using fluorescence dyes showed transient membrane hyperpolarization on hypoosmolality-induced motility. This article discusses the role of membrane hyperpolarization on removal of inactivation of Ca(2+) channels, leading to Ca(2+) influx at the initiation of carp sperm motility.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Proceedings of the National Academy of Sciences of the United States of America. - 97 : 5 (2000), p. 2052-2057. -
További szerzők:Márián Teréz (1950-) (radiobiológus) Izumi, Hiroko Damjanovich Sándor (1936-2017) (biofizikus) Balkay László (1963-) (biofizikus) Trón Lajos (1941-) (biofizikus) Morisawa, Masaaki
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4.

001-es BibID:BIBFORM005987
Első szerző:Pieri, Carlo
Cím:Ligand and voltage gated sodium channels may regulate electrogenic pump activity in human, mouse and rat lymphocytes / C. Pieri, R. Recchioni, F. Moroni, L. Balkay, T. Márián, L. Trón, S. Damjanovich
Dátum:1989
Megjegyzések:Bretylium tosylate - a sodium channel opener - resulted in an increase of membrane potential of depolarized human, rat and mouse T and B lymphocytes. Flow cytometric membrane potential measurements with bis-oxonol revealed that the above hyperpolarizing effect was amiloride, ouabain, tetrodotoxin, azide and temperature sensitive. The effect showed an absolute dependence on the extracellular sodium but it was insensitive to the extracellular Ca2+ level. The voltage gating of the effect can be eliminated by either an increase of the extracellular potassium concentration or low doses of veratrin. The existence of a voltage and ligand gated sodium channel is suggested in the plasma membrane of all kinds of lymphocytes. The hyperpolarization is explained by an increased activity of the electrogenic sodium-potassium ATP-ase. Induced opening of such sodium channels may regulate the electrogenic pump activity and indirectly cell activation.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Amiloride
Animal
B-Lymphocytes
Bretylium Tosylate
Calcium
Cell Membrane
drug effects
Dyes
Electrochemistry
Female
Flow Cytometry
Fluorescent Dyes
Human
Lymphocytes
Membrane Potentials
Mice
Mice,Inbred BALB C
Mice,Nude
pharmacology
physiology
Potassium
Rats
Sodium
Sodium Channels
Support,Non-U.S.Gov't
Tetrodotoxin
Thiobarbiturates
Megjelenés:Biochemical and Biophysical Research Communications. - 160 : 3 (1989), p. 999-1002. -
További szerzők:Recchioni, Rina Moroni, Fausto Balkay László (1963-) (biofizikus) Márián Teréz (1950-) (radiobiológus) Trón Lajos (1941-) (biofizikus) Damjanovich Sándor (1936-2017) (biofizikus)
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5.

001-es BibID:BIBFORM006056
Első szerző:Trón Lajos (biofizikus)
Cím:Bretylium causes a K(+)-Na+ pump activation that is independent of Na+/H+ exchange in depolarized rat, mouse and human lymphocytes / Tron, L., Pieri, C., Marian, T., Balkay, L., Emri, M., Damjanovich, S.
Dátum:1990
Megjegyzések:We have studied a bretylium tosylate induced increase of the membrane potentials of partially depolarized rat, mouse and human lymphocytes, using the potential sensitive dye, bis [1,3, dibutylbarbituric acid-(5) trimethine oxonol]. The extent of this repolarization is dose-dependent and decreased in magnitude as the temp was reduced from 37 degrees C to room temp. The repolarizing effect is inhibited by K(+)-Na(+)-pump blockers or lack of extracellular Na+. Sodium ion channel blockers are effective in abolishing repolarization only if applied prior to, or simultaneously with, bretylium. Activation of Na+/H+ exchange is not involved in the mechanism of the phenomenon as the latter is completely eliminated in the presence of 10 microM amiloride (concn of the diuretics having no measurable inhibition on the action of the exchanger). These data suggest that bretylium opens ligand- and voltage-gated Na+ channels, and repolarization occurs due to higher activity of the K(+)-Na(+)-pump stimulated by the enhanced intracellular Na+ accumulation.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Animal
Bretylium Compounds
Bretylium Tosylate
drug effects
Human
Hungary
In Vitro
Lymphocytes
Membrane Potentials
metabolism
Mice
Na(+)-K(+)-Exchanging ATPase
pharmacology
physiology
Potassium
Protons
Rats
Rats,Inbred Strains
Sodium
Support,Non-U.S.Gov't
Megjelenés:Molecular Immunology. - 27 : 12 (1990), p. 1307-1311. -
További szerzők:Pieri, Carlo Márián Teréz (1950-) (radiobiológus) Balkay László (1963-) (biofizikus) Emri Miklós (1962-) (fizikus) Damjanovich Sándor (1936-2017) (biofizikus)
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