Kinetics of Ca2+-activated K+ channels from rabbit muscle incorporated into planar bilayers: Vidence for a Ca2+ and Ba2+ blockade
Author
dc.contributor.author
Vergara Montecinos, Cecilia
Author
dc.contributor.author
Latorre, Ramón
Admission date
dc.date.accessioned
2019-01-29T14:20:46Z
Available date
dc.date.available
2019-01-29T14:20:46Z
Publication date
dc.date.issued
1983
Cita de ítem
dc.identifier.citation
Journal of General Physiology, Volumen 82, Issue 4, 2018, Pages 543-568
Identifier
dc.identifier.issn
15407748
Identifier
dc.identifier.issn
00221295
Identifier
dc.identifier.other
10.1085/jgp.82.4.543
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/160504
Abstract
dc.description.abstract
The interaction of Ca2+ and Ba2+ with a Ca2+-activated K+ channel from rabbit skeletal muscle membranes is studied in planar lipid bilayers. At [Ca2+]≥100 µM in the cis side (the side to which the vesicles are added) and at positive voltages, the channel kinetics consisted of bursts of activity interrupted by long periods of quiescence. We found that the reciprocal of the mean burst time increases linearly with [Ca2+], whereas the mean time for the quiescent (closed) periods is independent of [Ca2+]. The number of quiescent periods is reduced by increasing [K+]. Micromolar amounts of cis Ba2+ do not activate the channel, but induce similar "slow" closings. Also, in this case, the mean burst time is inversely proportional to the [Ba2+] and the mean closed time is independent of [Ba2+]. Raising [K+] either symmetrically or only in the trans side relieved the Ba2+ effect. trans Ba2+ also induces changes in the slow kinetics, but in millimolar amounts. These results suggest that the quiesc