Blocking Probability
Mostrando 25-36 de 52 artigos, teses e dissertações.
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25. Activation of ion channels in the frog endplate by several analogues of acetylcholine.
1. Single-ion-channel recording has been used to estimate the equilibrium concentration-response relationship for several acetylcholine analogues. The response, corrected for desensitization, was taken as the probability of a channel being open during clusters of openings that were separated by desensitized periods. 2. All agonists were able to block the cha
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26. Triple-barrel structure of inwardly rectifying K+ channels revealed by Cs+ and Rb+ block in guinea-pig heart cells.
1. The hypothesis that the inwardly rectifying K+ channel consists of a triple-barrel structure was investigated. Inward currents were recorded under the blocking effects of external Cs+ or Rb+ in the cell-attached configuration of the patch-clamp technique using single ventricular cells enzymatically isolated from guinea-pig hearts. 2. Cs+ (10-100 microM) o
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27. Open-channel block by internally applied amines inhibits activation gate closure in batrachotoxin-activated sodium channels.
We have studied the action of several pore-blocking amines on voltage-dependent activation gating of batrachotoxin(BTX)-activated sodium channels, from bovine heart and rat skeletal muscle, incorporated into planar lipid bilayers. Although structurally simpler, the compounds studied show general structural features and channel-inhibiting actions that resembl
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28. Dissecting lidocaine action: diethylamide and phenol mimic separate modes of lidocaine block of sodium channels from heart and skeletal muscle.
We have investigated block of sodium channels by diethylamide and phenol, which resemble the hydrophilic tertiary amine head and the hydrophobic aromatic tail of the lidocaine molecule, respectively. Diethylamide and phenol separately mimicked the fast and slow modes of block caused by lidocaine. Experiments were performed using single batrachotoxin-activate
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29. Three kinetically distinct potassium channels in mouse neuroblastoma cells.
1. Mouse neuroblastoma cells were utilized to examine the electrical properties of single K+ channels which might underlie multiple components of outward current in vertebrate neurones. The conductance, kinetics of activation, inactivation, and pharmacology of three types of channels were compared. 2. Two types of voltage-dependent channels, primarily permea
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30. Computerised linking of medical records: methodological guidelines.
OBJECTIVES--To report on the development of computer assisted methods for linking medical records and record abstracts. DESIGN--The methods include file blocking, to put records in an order which makes searching efficient; matching, which is the process of comparing records to determine whether they do or do not relate to the same person; linkage, which is t
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31. Effects of L-glutamate on the anomalous rectifier potassium current in horizontal cells of Carassius auratus retina.
The effects of externally applied L-glutamate (Glu) on K currents through the anomalous rectifier were studied in solitary horizontal cells dissociated from goldfish retinae under whole-cell voltage-clamp or cell-attached patch-clamp conditions using 'giga-seal' suction pipettes. In the whole-cell clamp experiments, hyperpolarization of the membrane below th
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32. Single inwardly rectifying potassium channels in cultured muscle cells from rat and mouse.
1. Inward unitary currents through inwardly rectifying K+ channels of myotubes derived from newborn rats or from a murine, clonal myoblast cell line were studied in the cell-attached configuration. Open-closed transitions of the channel were observed in the absence of blocking ions. 2. The single-channel conductance was 26.3 +/- 2.9 pS (mean + S.D., n = 14)
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33. Cross-talk between ATP-regulated K+ channels and Na+ transport via cellular metabolism in frog skin principal cells.
Isolated frog skin epithelium, mounted in an Ussing chamber and bathed in standard NaCl Ringer solution, recycles K+ across the basolateral membrane of principal cells through an inward-rectifier K+ channel (Kir) operating in parallel with a Na+-K+-ATPase pump. Here we report on the metabolic control of the Kir channel using patch clamping, short-circuit cur
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34. Interaction of Heparins and Dextran Sulfates with a Mesoscopic Protein Nanopore
A mechanism of how polyanions influence the channel formed by Staphylococcus aureus α-hemolysin is described. We demonstrate that the probability of several types of polyanions to block the ion channel depends on the presence of divalent cations and the polyanion molecular weight and concentration. For heparins, a 10-fold increase in molecular weight decrea
The Biophysical Society.
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35. Alternating translocation of protein substrates from both ends of ClpXP protease
In ClpXP protease complexes, hexameric rings of the ATP-dependent ClpX chaperone stack on one or both faces of the double-heptameric rings of ClpP. We used electron microscopy to record the initial binding of protein substrates to ClpXP and their accumulation inside proteolytically inactive ClpP. Proteins with N- or C-terminal recognition motifs bound to com
Oxford University Press.
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36. A Calcium-Selective Channel from Root-Tip Endomembranes of Garden Cress1
A Ca2+ channel from root-tip endomembranes of garden cress (Lepidium sativum L.) (LCC1) was characterized using the planar lipid-bilayer technique. Investigation of single-channel recordings revealed that LCC1 is voltage gated and strongly rectifying. In symmetrical 50 mm CaCl2 solutions, the single-channel conductance was 24 picosiemens. LCC1 showed a
American Society of Plant Physiologists.