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1.

001-es BibID:BIBFORM018458
Első szerző:Kecskeméti Valéria
Cím:Norfluoxetine and fluoxetine have similar anticonvulsant and Ca channel blocking potencies / Kecskeméti V., Rusznák Z., Riba P., Pál B., Wagner R., Harasztosi C., Nánási P. P., Szűcs G.
Dátum:2005
ISSN:0361-9230
Megjegyzések:Norfluoxetine is the most important active metabolite of the widely used antidepressant fluoxetine but little is known about its pharmacological actions. In this study the anticonvulsant actions of norfluoxetine and fluoxetine were studied and compared to those of phenytoin and clonazepam in pentylenetetrazol-induced mouse epilepsy models. Pretreatment with fluoxetine or norfluoxetine (20 mg/kg s.c.), as well as phenytoin (30 mg/kg s.c.) and clonazepam (0.1 mg/kg s.c.) significantly increased both the rate and duration of survival, demonstratinga significant protective effect against pentylenetetrazol-induced epilepsy. These effects of norfluoxetine were similar to those of fluoxetine. According to the calculated combined protection scores, both norfluoxetine and fluoxetine were effective from the concentration of 10 mg/kg,while the highest protective action was observed with clonazepam. Effects of norfluoxetine and fluoxetine on voltage-gated Ca2+ channels were evaluated by measuring peak Ba2+ current flowing through the Ca2+ channels upon depolarization using whole cell voltage clamp in enzymatically isolated rat cochlear neurons. The current was reduced equally in a concentration-dependent manner by norfluoxetine (EC50 = 20.4?2.7M, Hill coefficient = 0.86?0.1) and fluoxetine(EC50 = 22.3?3.6M, Hill coefficient = 0.87?0.1). It was concluded that the efficacy of the two compounds in neuronal tissues was equal, either in preventing seizure activity or in blockingthe neuronal Ca2+ channels.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Fluoxetine
Norfluoxetine
Anticonvulsants
Neuronal Ca2+ currents
Voltage clamp
Megjelenés:Brain Research Bulletin. - 67 : 1-2 (2005), p. 126-132. -
További szerzők:Rusznák Zoltán (1965-) (élettanász) Riba Pál Pál Balázs (1975-) (élettanász) Wagner Róbert Harasztosi Csaba Nánási Péter Pál (1956-) (élettanász) Szűcs Géza (1948-) (élettanász)
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2.

001-es BibID:BIBFORM030258
035-os BibID:WOS:000181565400020
Első szerző:Magyar János (élettanász)
Cím:Differential effects of fluoxetine enantiomers in mammalian neural and cardiac tissues / János Magyar, Zoltán Rusznák, Csaba Harasztosi, Ágnes Körtvély, Pál Pacher, Tamás Bányász, Csaba Pankucsi, László Kovács, Géza Szűcs, Péter P. Nánási, Valéria Kecskeméti
Dátum:2003
ISSN:1107-3756
Megjegyzések:Racemic fluoxetine is a widely used SSRI antidepressant compound having also anticonvulsant effect. In addition, it was shown that it blocked several types of voltage gated ion channels including neural and cardiac calcium channels. In the present study the effects of enantiomers of fluoxetine (R(-)-fluoxetine and S(+)-fluoxetine) were compared on neuronal and cardiac voltage-gated Ca2+ channels using the whole cell configuration of patch clamp techniques, and the anticonvulsant action of these enantiomers was also evaluated in a mouse epilepsy model. In isolated pyramidal neurons of the dorsal cochlear nucleus of the rat the effect of fluoxetine (S(+), R(-) and racemic) was studied on the Ca2+ channels by measuring peak Ba2+ current during ramp depolarizations. All forms of fluoxetine reduced the Ba2+ current of the pyramidal cells in a concentration-dependent manner, with a K, value of 22.3 +/- 3.6 muM for racemic fluoxetine. This value of K, was higher by one order of magnitude than found in cardiac myocytes with fluoxetine enantiomers (2.4 +/- 0.1 and 2.8 +/- 0.2 muM). Difference between the effects of the two enantiomers on neuronal Ba2+, current was observed only at 5 muM concentration: R(-)-fluoxetine inhibited 28 +/- 3% of the peak current, while S(+)-fluoxetine reduced the current by 18 +/- 2% (n=13, P<0.05). In voltage clamped canine ventricular cardiomyocytes both enantiomers of fluoxetine caused a reversible concentration-dependent block of the peak Ca2+ current measured at 0 mV. Significant differences between the two enantiomers in this blocking effect was observed at low concentrations only: S(+)-fluoxetine caused a higher degree of block than R(-)-fluoxetine (56.3 +/- 2.2% versus 49.1 +/- 2.2% and 95.5 +/- 0.9% versus 84.5 +/- 3.1% block with 3 and 10 &mu;M S(+) and R(-)-fluoxetine, respectively, P<0.05, n=5). Studied in current clamp mode, micromolar concentrations of fluoxetine shortened action potential duration of isolated ventricular cells, while higher concentrations also suppressed maximum velocity of depolarization and action potential amplitude. This shortening effect was significantly greater in the case of S(+) than R(-)-fluoxetine at 1 and 3 muM concentrations, whereas no differences in their effects on depolarization were observed. In pentylenetetrazole-induced mouse epilepsy model fluoxetine pretreatment significantly increased the 60 min survival rate, survival duration and seizure latency. These effects were more pronounced with the R(-) than the S(+) enantiomer. The results indicate that fluoxetine exerts much stronger suppressive effect on cardiac than neuronal calcium channels. At micromolar concentrations (between 1 and 10 muM) R(-)-fluoxetine is more effective than the S(+) enantiomer on neuronal, while less effective on cardiac calcium channels. The stronger anticonvulsant effect of the R(-) enantiomer may, at least partially, be explained by these differences. Used as an antidepressant or anticonvulsant drug, less severe cardiac side-effects are anticipated with the R(-) enantiomer.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:International Journal of Molecular Medicine. - 11 : 4 (2003), p. 535-542. -
További szerzők:Rusznák Zoltán (1965-) (élettanász) Harasztosi Csaba Körtvély Ágnes Pacher Pál Bányász Tamás (1960-) (élettanász) Pankucsi Csaba (farmakológus) Kovács László (1939-) (élettanász) Szűcs Géza (1948-) (élettanász) Nánási Péter Pál (1956-) (élettanász) Kecskeméti Valéria
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3.

001-es BibID:BIBFORM018463
Első szerző:Pál Balázs (élettanász)
Cím:Depolarization-activated K+ currents of the bushy neurones of the rat cochlear nucleus in a thin brain slice preparation / Pál B., Rusznák Z., Harasztosi C., Szücs G.
Dátum:2004
Megjegyzések:Depolarization-activated outward currents of bushy neurones of 6-14-day-old Wistar rats have been investigated in a brain slice preparation. Under current-clamp, the cells produced a single action potential at the beginning of suprathreshold depolarizing current steps. On voltage-clamp depolarizations, the cells produced a mixed outward K+ current that included a component with rapid activation and rapid inactivation, little TEA+ sensitivity, a half-inactivation voltage of -77 +/- 2 mV (T = 25 degrees C; n = 7; Mean +/- S.E.M.) and single-exponential recovery from inactivation (taurecovery= 12 +/- 1 ms at -100 mV; n=3). This transient component was identified as an A-type K+ current. Bushy cells developed a high-threshold TEA-sensitive K+ current that exhibited less prominent inactivation. These characteristics suggested that this current was associated with the activation of delayed rectifier K+ channels. Bushy neurones also possessed a low-threshold outward K+ current that showed partial inactivation and high 4-aminopyridine sensitivity. Part of this current component was blocked by 200 nmol/l dendrotoxin-I. Application of 100 micromol/l 4-aminopyridine changed the firing behaviour of the bushy neurones from the primary-like pattern to a much less rapidly adapting one, suggesting that the low-threshold current might have important roles in maintaining the physiological function of the cells.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény hazai lapban
cochlear nucleus
bushy cell
outward K+ currents
dendrotoxin-I
4-aminopyridine
Megjelenés:Acta Physiologica Hungarica. - 91 : 2 (2004), p. 83-98. -
További szerzők:Rusznák Zoltán (1965-) (élettanász) Harasztosi Csaba Szűcs Géza (1948-) (élettanász)
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Intézményi repozitóriumban (DEA) tárolt változat
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4.

001-es BibID:BIBFORM040769
Első szerző:Szabo Zsolt
Cím:A detailed procedure and dissection guide for the isolation of spiral ganglion cells of the guinea pig for electrophysiological experiments / Szabó, Zs., Harasztosi, Cs., Szűcs, G., Sziklai, I., Rusznák, Z.
Dátum:2003
ISSN:1385-299X
Megjegyzések:In the present study step-by-step instructions are provided for a preparative technique employed for the removal of the spiral ganglion from the inner ear of the guinea pig. Removal of the temporal bone is followed by opening of the bulla and excision of the modiolus. All major steps of the technique are illustrated with photographs. A procedure to obtain surviving, acutely separated spiral ganglion neurones is also described. By this procedure small tissue pieces are removed from the modiolus which contain the spiral ganglion neurones. The tissue fragments then undergo a mild enzyme treatment (collagenase and pronase). After the enzyme exposure, the tissue pieces are gently triturated, and the isolated cells are allowed to settle. Poly-D-lysine ensured the firm attachment of the spiral ganglion cells to the cover-slips. The application of this adhesive coating seemed to be desirable in functional studies when microelectrode techniques and/or rapid exchange of the extracellular solution were employed.
Tárgyszavak:Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Brain Research Protocols. - 10 : 3 (2003), p. 139-147. -
További szerzők:Harasztosi Csaba Szűcs Géza (1948-) (élettanász) Sziklai István (1954-) (fül-orr-gégész) Rusznák Zoltán (1965-) (élettanász)
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Intézményi repozitóriumban (DEA) tárolt változat
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5.

001-es BibID:BIBFORM039760
035-os BibID:PMID:12453052
Első szerző:Szabo Zsolt
Cím:Ionic currents determining the membrane characteristics of type I spiral ganglion neurons of the guinea pig / Zs. Szabó, Cs. Harasztosi, I. Sziklai, G. Szűcs, Z. Rusznák
Dátum:2002
ISSN:0953-816X
Megjegyzések:Enzymatically isolated type I spiral ganglion neurons of the guinea pig have been investigated in the present study. The identity of the cells was confirmed by using anti-neuron-specific enolase immunostaining. The presence and shredding of the myelin sheath was also documented by employing anti-S100 immunoreaction. The membrane characteristics of the cells were studied by using the whole-cell patch-clamp technique. The whole-cell capacitance of the cells was 9 +/- 2 pF (n = 51), while the resting membrane potential of the cells was -62 +/- 9 mV (n = 19). When suprathreshold depolarizing stimuli were applied, the neurons fired a single action potential at the beginning of the stimulation. It was confirmed in this study that type I spiral ganglion cells possess a hyperpolarization-activated nonspecific cationic current (Ih). The major characteristics of this current component were unaffected by the enzyme treatment. Type I spiral ganglion cells also expressed various depolarization-activated K+ current components. A high-threshold outward current was sensitive to 1-10 mm TEA+ application. The ganglion cells also expressed a relatively small, but nevertheless present, transient outward current component which was less sensitive to TEA+ but could be inhibited by 100 micro m 4-aminopyridine. A DTX-I-sensitive current was responsible for some 30% of the total outward current (at 0 mV), showed rapid activation at membrane potentials positive to -50 mV and demonstrated very little inactivation. However, inhibition of the highly 4-AP- or DTX-I-sensitive component did not alter the rapidly inactivating nature of the firing pattern of the cells.
Tárgyszavak:Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:European Journal of Neuroscience. - 16 : 10 (2002), p. 1887-1895. -
További szerzők:Harasztosi Csaba Sziklai István (1954-) (fül-orr-gégész) Szűcs Géza (1948-) (élettanász) Rusznák Zoltán (1965-) (élettanász)
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Intézményi repozitóriumban (DEA) tárolt változat
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6.

001-es BibID:bibEBI13804
Első szerző:Szabó Zsolt
Cím:Tengerimalacból izolált I. típusú ganglion spirale neuron depolarizációja által kiváltott K+ áramok jellemzése / Szabó, Zs., Harasztosi, Cs., Kovács, I., Szűcs, G., Rusznák, Z., Sziklai, I.
Dátum:2003
Tárgyszavak:Orvostudományok Klinikai orvostudományok magyar nyelvű folyóiratközlemény hazai lapban
Megjelenés:Fül-Orr-Gégegyógyászat. - 49 (2003), p. 114-123. -
További szerzők:Harasztosi Csaba Kovács Ilona (1965-) (patológus) Szűcs Géza (1948-) (élettanász) Rusznák Zoltán (1965-) (élettanász) Sziklai István (1954-) (fül-orr-gégész)
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