CCL

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1.

001-es BibID:BIBFORM083093
Első szerző:Almássy János (élettanász, biológus, angol-magyar szakfordító)
Cím:Investigation of BK Channel Gating using Mallotoxin / Almassy Janos, Begenisich Ted
Dátum:2011
ISSN:0006-3495
Tárgyszavak:Orvostudományok Elméleti orvostudományok idézhető absztrakt
folyóiratcikk
Megjelenés:Biophysical Journal. - 100 : 3 (2011), p. 583a. -
További szerzők:Begenisich, Ted B.
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DOI
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2.

001-es BibID:BIBFORM049387
Első szerző:Almássy János (élettanász, biológus, angol-magyar szakfordító)
Cím:Apical Ca2+-activated K+-channels in mouse parotid acinar cells / Janos Almassy, Ted Begenisich, David Yule
Dátum:2012
ISSN:0006-3495
Megjegyzések:Ca2+ activation of Cl-- and K+-channels are key events underlying stimulated fluid secretion from parotid salivary glands. Cl--channels are exclusively present on the apical plasma membrane (PM) while the localization of K+-channels has not been established. Mathematical models have suggested that localization of some K+-channels to the apical PM is optimum for fluid secretion. A combination of whole cell electrophysiology and temporally resolved digital imaging with local manipulation of intracellular [Ca2+] was used to investigate if Ca2+-activated K+-channels are present in the apical PM of parotid acinar cells. Initial experiments established Ca2+ buffering conditions that produced brief, localized increases in [Ca2+] following focal laser photolysis of caged-Ca2+. Conditions were employed to isolate K+ and Cl- conductances. Photolysis at the apical PM resulted in a robust increase in K+ and Cl- currents. A localized reduction in [Ca2+] at the apical PM following photolysis of Diazo-2, a caged-Ca2+ chelator, resulted in a decrease in both K+ and Cl- currents. The K+ currents evoked by apical photolysis were partially blocked by both paxilline and TRAM-34, specific blockers of BK and IK respectively and almost abolished by incubation with both antagonists. Apical TRAM-34 sensitive K+ currents were also observed in BK null parotid acini. In contrast, when the [Ca2+] was increased at the basal PM no increase in either K+ or Cl- currents was evoked. These data provide strong evidence that K+- and Cl--channels are similarly distributed in the apical PM. Furthermore, both IK and BK channels are present in this domain and that the density of these channels appears higher in the apical vs. basal PM. In total, this study provides support for a model in which fluid secretion is optimized following expression of K+-channels specifically in the apical PM.
Tárgyszavak:Természettudományok Biológiai tudományok idézhető absztrakt
calcium release
Megjelenés:Biophysical Journal. - 102 : 3 (2012), p. 650a-651a. -
További szerzők:Begenisich, Ted B. Yule, David I.
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3.

001-es BibID:BIBFORM049160
035-os BibID:PMID:21984254
Első szerző:Almássy János (élettanász, biológus, angol-magyar szakfordító)
Cím:The LRRC26 protein selectively alters the efficacy of BK channel activators / Janos Almassy, Ted B. Begenisich
Dátum:2012
ISSN:0026-895X
Megjegyzések:Large conductance, Ca2+-activated K channel proteins are involved in a wide range of physiological activities, so there is considerable interest in the pharmacology of large conductance calcium-activated K (BK) channels. One potent activator of BK channels is mallotoxin (MTX), which produces a very large hyperpolarizing shift of the voltage gating of heterologously expressed BK channels and causes a dramatic increase in the activity of BK channels in human smooth muscle cells. However, we found that MTX shifted the steady-state activation of BK channels in native parotid acinar cells by only 6 mV. This was not because the parotid BK isoform (parSlo) is inherently insensitive to MTX as MTX shifted the activation of heterologously expressed parSlo channels by 70 mV. Even though MTX had a minimal effect on steady-state activation of parotid BK channels, it produced an approximate 2-fold speeding of the channel-gating kinetics. The BK channels in parotid acinar cells have a much more hyperpolarized voltage activation range than BK channels in most other cell types. We found that this is probably attributable to an accessory protein, LRRC26, which is expressed in parotid glands: expressed parSlo + LRRC26 channels were resistant to the actions of MTX. Another class of BK activators is the benzimidazalones that includes 1,3-dihydro-1-(2-hydroxy-5-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-2H-benzimidazol-2-one (NS-1619). Although the LRRC26 accessory protein strongly inhibited the ability of MTX to activate BK channels, we found that it had only a small effect on the action of NS-1619 on BK channels. Thus, the LRRC26 BK channel accessory protein selectively alters the pharmacology of BK channels.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
parotid cell
Megjelenés:Molecular Pharmacology. - 81 : 1 (2012), p. 21-30. -
További szerzők:Begenisich, Ted B.
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4.

001-es BibID:BIBFORM049159
035-os BibID:PMID:22291145
Első szerző:Almássy János (élettanász, biológus, angol-magyar szakfordító)
Cím:Apical Ca2+-activated potassium channels in mouse parotid acinar cells / Janos Almassy, Jong Hak Won, Ted B. Begenisich, David I. Yule
Dátum:2012
Megjegyzések:Ca2+ activation of Cl and K channels is a key event underlying stimulated fluid secretion from parotid salivary glands. Cl channels are exclusively present on the apical plasma membrane (PM), whereas the localization of K channels has not been established. Mathematical models have suggested that localization of some K channels to the apical PM is optimum for fluid secretion. A combination of whole cell electrophysiology and temporally resolved digital imaging with local manipulation of intracellular [Ca2+] was used to investigate if Ca2+-activated K channels are present in the apical PM of parotid acinar cells. Initial experiments established Ca2+-buffering conditions that produced brief, localized increases in [Ca2+] after focal laser photolysis of caged Ca2+. Conditions were used to isolate K+ and Cl? conductances. Photolysis at the apical PM resulted in a robust increase in K+ and Cl? currents. A localized reduction in [Ca2+] at the apical PM after photolysis of Diazo-2, a caged Ca2+ chelator, resulted in a decrease in both K+ and Cl? currents. The K+ currents evoked by apical photolysis were partially blocked by both paxilline and TRAM-34, specific blockers of large-conductance "maxi-K" (BK) and intermediate K (IK), respectively, and almost abolished by incubation with both antagonists. Apical TRAM-34?sensitive K+ currents were also observed in BK-null parotid acini. In contrast, when the [Ca2+] was increased at the basal or lateral PM, no increase in either K+ or Cl? currents was evoked. These data provide strong evidence that K and Cl channels are similarly distributed in the apical PM. Furthermore, both IK and BK channels are present in this domain, and the density of these channels appears higher in the apical versus basolateral PM. Collectively, this study provides support for a model in which fluid secretion is optimized after expression of K channels specifically in the apical PM.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
parotid cell
Megjelenés:Jopurnal of General Physiology. - 139 : 2 (2012), p. 121-133. -
További szerzők:Won, Jong Hak Begenisich, Ted B. Yule, David I.
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