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001-es BibID:BIBFORM004643
Első szerző:Berecki G.
Cím:Anion channels in chara corallina tonoplast membrane : calcium dependence and rectification / Berecki, G., Varga, Z., Van Iren, F., Van Duijn, B.
Dátum:1999
Megjegyzések:Tonoplast K(+) channels of Chara corallina are well characterized but only a few reports mention anion channels, which are likely to play an important role in the tonoplast action potential and osmoregulation of this plant. For experiments internodal cells were isolated. Cytoplasmic droplets were formed in an iso-osmotic bath solution according to a modified procedure. Ion channels with conductances of 48 pS and 170 pS were detected by the patch-clamp technique. In the absence of K(+) in the bath solution the 170 pS channel was not observed at negative pipette potential values. When Cl(-) on either the vacuolar side or the cytoplasmic side was partly replaced with F(-), the reversal potential of the 48 pS channel shifted conform to the Cl(-) equilibrium potential with similar behavior in droplet-attached and excised patch mode. These results showed that the 48 pS channel was a Cl(-) channel. In droplet-attached mode the channel rectified outward current flow, and the slope conductance was smaller. When Chara droplets were formed in a bath solution containing low (10(-8) m) Ca(2+), then no Cl(-) channels could be detected either in droplet-attached or in inside-out patch mode. Channel activity was restored if Ca(2+) was applied to the cytoplasmic side of inside-out patches. Rectification properties in the inside-out patch configuration could be controlled by the holding pipette potential. Holding potential values negative or positive to the calculated reversal potential for Cl(-) ions induced opposite rectification properties. Our results show Ca(2+)-activated Cl(-) channels in the tonoplast of Chara with holding potential dependent rectification
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Action Potentials
agonists
Algae, Green
Animal
Anions
antagonists and inhibitors
Calcium
Cesium
Chloride Channels
Chlorides
cytology
Cytoplasm
drug effects
Electric Conductivity
Fluorine
Ion Channel Gating
metabolism
Osmolar Concentration
Patch-Clamp Techniques
pharmacology
Plant Proteins
Potassium
Potassium Channels
Sodium
Substrate Specificity
Support, Non-U.S.Gov't
Vacuoles
Zinc
Megjelenés:The Journal of Membrane Biology. - 172 : 2 (1999), p. 159-168. -
További szerzők:Varga Zoltán (1969-) (biofizikus, szakfordító) Iren, F., Van Duijn, B., Van
Internet cím:elektronikus változat
DOI
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