Please use this identifier to cite or link to this item: http://repositorio.unifesp.br/handle/11600/27269
Title: Voltage-gated potassium currents in rat vas deferens smooth muscle cells
Authors: Harhun, M. I.
Jurkiewicz, A.
Jurkiewicz, N. H.
Kryshtal, D. O.
Shuba, M. F.
Vladimirova, I. A.
Bogomoletz Inst Physiol
Universidade Federal de São Paulo (UNIFESP)
Keywords: vas deferens
smooth muscle
A-type potassium current
delayed rectifying potassium current
4-aminopyridine
clofilium
Issue Date: 1-Jun-2003
Publisher: Springer
Citation: Pflugers Archiv-european Journal of Physiology. New York: Springer-verlag, v. 446, n. 3, p. 380-386, 2003.
Abstract: Voltage-gated components of the outward current in single smooth muscle cells isolated from the epididymal part of the rat vas deferens were studied using amphotericin B perforated patch-clamp techniques. the complex kinetics of the net outward current elicited by positive voltage steps from -80 mV to +40 mV suggested the presence of several components. Bath application of 200 nM charybdotoxin, a potent blocker of large-conductance, Ca2+-dependent K+ channels (BKCa), reduced the current amplitude significantly. When BKCa channels were suppressed, fast-inactivating (I-K,I-f) and delayed rectifying (I-K,I-dr) components of the outward current were identified. I-K,I-f was characterized by fast kinetics of current decay, negative steady-state activation and inactivation dependencies and sensitivity to 4-aminopyridine with an apparent K-d of 0.32 mM, properties similar to those of the A-type K+ current. in contrast, I-K,I-dr activated and inactivated at more positive potentials. the time constant of activation of I-K,I-dr was voltage dependent with an e-fold decrease per 21 mV depolarization. I-K,I-dr was inhibited by clofilium, a blocker of voltage-gated K+ channels, with an IC50 of 12 muM and was not blocked by 5 mM 4-aminopyridine. the possible significance of the voltage-gated currents is discussed.
URI: http://repositorio.unifesp.br/handle/11600/27269
ISSN: 0031-6768
Other Identifiers: http://dx.doi.org/10.1007/s00424-002-0986-7
Appears in Collections:Em verificação - Geral

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