A K+ channel in Xenopus nerve fibres selectively blocked by bee and snake toxins: binding and voltage-clamp experiments.
نویسندگان
چکیده
منابع مشابه
Voltage-dependent conformational changes in human Ca(2+)- and voltage-activated K(+) channel, revealed by voltage-clamp fluorometry.
Large conductance voltage- and Ca(2+)-activated K(+) (BK(Ca)) channels regulate important physiological processes such as neurotransmitter release and vascular tone. BK(Ca) channels possess a voltage sensor mainly represented by the S4 transmembrane domain. Changes in membrane potential displace the voltage sensor, producing a conformational change that leads to channel opening. By site-directe...
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Passive transport of potassium through the plasma membrane of a protoplasmic droplet isolated from large internodal cells of Chara corallina Klein ex Willd., em, R.D.W. has been investigated using the patchclamp technique. When the membrane is hyperpolarized the conductance of a single K(+)-channel is of the order of magnitude of 100 picoSiemens and is reduced by tetraethylammonium chloride. It...
متن کاملVoltage Clamp Experiments in Striated Muscle Fibers
1. Membrane currents during step depolarizations were determined by a method in which three electrodes were inserted near the end of a fibre in the frog's sartorius muscle. The theoretical basis and limitations of the method are discussed.2. Measurements of the membrane capacity (C(M)) and resting resistance (R(M)) derived from the current during a step change in membrane potential are consiste...
متن کاملVoltage clamp fluorimetry studies of mammalian voltage-gated K(+) channel gating.
VCF (voltage clamp fluorimetry) provides a powerful technique to observe real-time conformational changes that are associated with ion channel gating. The present review highlights the insights such experiments have provided in understanding Kv (voltage-gated potassium) channel gating, with particular emphasis on the study of mammalian Kv1 channels. Further applications of VCF that would contri...
متن کاملControl of Gastric H,K-ATPase Activity by Cations, Voltage and Intracellular pH Analyzed by Voltage Clamp Fluorometry in Xenopus Oocytes
Whereas electrogenic partial reactions of the Na,K-ATPase have been studied in depth, much less is known about the influence of the membrane potential on the electroneutrally operating gastric H,K-ATPase. In this work, we investigated site-specifically fluorescence-labeled H,K-ATPase expressed in Xenopus oocytes by voltage clamp fluorometry to monitor the voltage-dependent distribution between ...
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ژورنال
عنوان ژورنال: The Journal of Physiology
سال: 1990
ISSN: 0022-3751
DOI: 10.1113/jphysiol.1990.sp017918