Allosteric Block of KCa2 Channels by Apamin
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چکیده
منابع مشابه
Determinants of apamin and d-tubocurarine block in SK potassium channels.
Small conductance calcium-activated potassium channels show a distinct pharmacology. Some, but not all, are blocked by the peptide toxin apamin, and apamin-sensitive channels are also blocked by d-tubocurarine. Cloned SK channels (small conductance calcium-activated potassium channel) recapitulate these properties. We have investigated the structural basis for these differences and found that t...
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Results In PC12 cells stably expressing rat P2Y1 receptors (PC12P2Y1), but not in wild type PC12 cells (PC12-wt), ADP induced rises in intracellular Ca2+ with half-maximal effects at 15 ± 1.3 μM. In whole-cell patch-clamp recordings, ADP inhibited ICa of PC12-P2Y1 cells (EC50: 6.3 ± 1.7 μM) and of PC12-wt (EC50: 3.8 ± 1.3 μM); this effect was not altered by the P2Y1 antagonist MRS 2216 (1 μM), ...
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Small conductance calcium-activated potassium channels (KCa2.1,2.2,2.3) are blocked with high affinity by both peptide toxins (e.g. apamin) and small molecule blockers (e.g. UCL 1848). In electrophysiological experiments, apamin shows subtype selectivity with IC50s of ∼100 pM and ∼1 nM for block KCa2.2 and KCa2.3 respectively. In binding studies, however, apamin appears not to discriminate betw...
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Ivermectin acts as a positive allosteric regulator of several ligand-gated channels including the glutamate-gated chloride channel (GluCl), gamma aminobutyric acid type-A receptor, glycine receptor, neuronal alpha7-nicotinic receptor and purinergic P2X4 receptor. In most of the ivermectin-sensitive channels, the effects of ivermectin include the potentiation of agonist-induced currents at low c...
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Activation of large conductance Ca(2+)-activated K(+) channels is controlled by both cytoplasmic Ca(2+) and membrane potential. To study the mechanism of voltage-dependent gating, we examined mSlo Ca(2+)-activated K(+) currents in excised macropatches from Xenopus oocytes in the virtual absence of Ca(2+) (<1 nM). In response to a voltage step, I(K) activates with an exponential time course, fol...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2010
ISSN: 0021-9258
DOI: 10.1074/jbc.m110.110072