tetraethylammonium

..1 subunits. Compared with Kv2.1 currents in expression systems, the Kv2.1 current in neocortical pyramidal cells activated and inactivated at relatively negative potentials and was very sensitive to holding potential...

..b>Tetraethylammonium (TEA(+)), a K(v) blocker, attenuated cell proliferation in a concentration-dependent manner...

..displayed rapid activation and deactivation kinetics, and was selectively blocked by a low concentration of tetraethylammonium (TEA; 1 mM). 4...

b>Tetraethylammonium (TEA) induces a form of long-term potentiation (LTP) that is independent on N-methyl-D-aspartate (NMDA) receptor activation (LTP(K)). LTP(K) may be a suitable chemical model to study molecular mechanisms underlying LTP...

..In contrast to previous reports based on slower and less sensitive assays, we found no effects of tetraethylammonium ions (TEA+) and acetazolamide on Lp...

..of equine chondrocyte Kv currents showed them to be powerfully inhibited by the potassium channel blockers tetraethylammonium and 4-aminopyridine but not by dendrotoxin-I. Immunohistochemical studies using polyclonal antibodies to Kv1...

..Application of internal tetraethylammonium (an open channel blocker) induced Off charge immobilization for large depolarizations, suggesting that the ..

..OCT2p-mediated uptake of the prototypical organic cation [14C]tetraethylammonium ([14C]TEA) into 293 cells was saturable...

..studied the activation and inhibition of the mouse muscle adult-type nicotinic acetylcholine receptor by tetraethylammonium (TEA) and related quaternary ammonium derivatives...

..Collectively, these data distinguish between open-state and closed-state inactivation, and suggest the presence of multiple possible mechanisms of inactivation coexisting in Kv1 channels...

..The architecture of the pore establishes the physical principles underlying selective K+ conduction...

..Our results indicate that acute oxidative stress has neuron- and conductance-specific actions in intestinal neurons that may underlie pathophysiological conditions...

..rat superior cervical ganglion (SCG) neurons, by comparing the block of these currents produced by tetraethylammonium (TEA) with the block of currents generated by a tandem KCNQ3/2 construct...

..METHODS: The transcellular transport and accumulation of [14C]creatinine and [14C]tetraethylammonium (TEA) were assessed using LLC-PK1 cell monolayers cultured on porous membrane filters...

..Finally, native or recombinant channels inhibited by muscarinic agonists can be activated by PIP(2). Our data strongly suggest that PIP(2) acts as a membrane-diffusible second messenger to regulate directly the activity of KCNQ currents...

..the side chain at position 470 makes it possible for the mutant channel, unlike native Shaker, to close with tetraethylammonium (TEA+) or the long-chain TEA-derivative C10+ trapped inside the channel...

..These results indicate that S6(T) residues have an influence on the conformation of the open activation gate, reflected in both the stability of the open state and the energy barriers it presents to ions...

..1 can be distinguished by the sensitivity to intracellular tetraethylammonium and extracellular potassium and lead to the same inactivated conformation. The functional properties of Kv2...

..We introduce the term U-type inactivation for the mechanism that is dominant in Kv2.1 and Kv3.1. U-type inactivation also makes a major but previously unrecognized contribution to slow inactivation of Shaker...

Intracellular tetraethylammonium (TEA) inhibition was studied at the single-channel level in the KcsA potassium channel reconstituted in planar lipid bilayers...

..These observations argue that between the intracellular solution and the QA-binding locus, there exists a constricted pathway, whose dimension ( approximately 9 A) is comparable to that of a K+ ion with a single H2O shell...

..These results lead to a refined picture of the number and location of ion binding sites at the inner end of the pore in Shaker K channels...

The location of the tetraethylammonium (TEA) binding site in the outer vestibule of K+ channels, and the mechanism by which external TEA slows C-type inactivation, have been considered well-understood...

..We show that in a Shaker K+ channel, the extracellular ends of S1 and S3 are approximately 30 ¿ from the tetraethylammonium (TEA) blocking site at the external opening of the pore...

..of a tyrosine residue, just downstream of the pore signature sequence GYG, determines sensitivity to tetraethylammonium (TEA). The KCNQ family of channels has a variety of amino acid residues in the equivalent position...

..These results provide information on the fine-structure of ion interactions with the inner end of the pore in K+ channels...

..These results suggest that important structural differences between sqKv1A homotetramers and native squid channels are likely to exist around the external and internal mouths of the pore...

..Several mutations in the P region affect tetraethylammonium binding but have minimal effects on longer blockers, suggesting that the hydrophobic tail contributes to ..

..Here, we determined the specificity, potency, and binding site of tetraethylammonium (TEA) to block Aquaporin water permeability...

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..A useful probe for the pore of potassium-selective channels is the organic ion tetraethylammonium (TEA), which binds with millimolar affinity to the intracellular opening of the pore and blocks potassium ..

..BaCl(2), a K(IR) blocker), and 100 nM iberiotoxin (a BK(Ca) blocker), but was nearly abolished by 10 mM tetraethylammonium (TEA, a non-selective potassium channel blocker)...

..only after opening, remaining trapped in closed channels, and that in the open state it competes with tetraethylammonium for binding...

..with the native V438 inactivate very slowly, and the canonical foot-in-the-door effect of extracellular tetraethylammonium (TEA) is not only absent, but the time course of slow inactivation is accelerated by TEA...

Open-channel blockers such as tetraethylammonium (TEA) have a long history as probes of the permeation pathway of ion channels...

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..A lack of competition with either agitoxin or tetraethylammonium indicates that BrMT binds channel subunits outside of the external pore region in an allosterically ..

..b>Tetraethylammonium (TEA) blocks ion conduction through potassium channels in a voltage-dependent manner from both sides of the ..

..This bend would occur at a Pro-X-Pro sequence that is highly conserved in Kv channels, near the site of activation gating...

..To examine mechanisms underlying the plateau, we studied the effects of potassium channel blockers tetraethylammonium (TEA) and 4-aminopyridine (4-AP) on membrane potentials in CM from rats on gestation Days 14, 15, 16, 21 (..

..This report represents the first functional and molecular characterization of Kv channels in mouse CB chemoreceptor cells, and strongly suggests that O(2)-sensitive Kv channels in this preparation belong to the Kv3 subfamily...

..Moreover, the insensitivity of Kv2.1 current magnitude to changes in K+ driving force promotes a more uniform modulation of current over a wide range of membrane potentials by the K+-dependent regulation of outer vestibule conformation...

..In agreement with experiment the Et4N+ blocker shows several kcal/mol better binding than the other tetraalkylammonium ions...

..We examined the ionic strength dependence of extracellular block of Shaker K+ channels by tetraethylammonium ions (TEA+) and by a trivalent quaternary ammonium ion, gallamine3+...

Extracellular tetraethylammonium (TEA+) inhibits the current carried out by K+ ions in potassium channels...

..b>Tetraethylammonium chloride (TEA; 0...

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..E-4031 also inhibited tetraethylammonium (TEA)-insensitive outward current indicating that the ERG K+ current is operating at depolarizing potentials...

..related gene product (HERG) channel is a form of C-type inactivation and is decelerated by external tetraethylammonium (TEA) and potassium...

..Our analysis further suggests that the four K(+) sites in the selectivity filter are spaced between 20 and 25% of the membrane electric field...

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We report results from automated docking and microscopic molecular dynamics simulations of the tetraethylammonium (TEA) complexes with KcsA...

..This was accompanied by the occurrence of a highly tetraethylammonium (TEA)- and quinine-sensitive delayed rectifier current, which gradually masked a rapidly inactivating A-type ..

..The H9c2 I(Kur) can be completely blocked by tetraethylammonium and 4-aminopyridine...

..These data suggest that the A-type current in murine antral smooth muscle cells is likely to be due to Kv4 channels. This current contributes to the maintenance of negative resting membrane potentials...

..I(Kv) in neonates was insensitive to a high concentration of tetraethylammonium (TEA, 10 mM) but blocked 4-aminopyridine (4-AP, IC(50)=0.5+/-0...

..medium, and this long-term depolarizing effect of PACAP was mimicked by the I(K) specific blocker tetraethylammonium chloride (TEA)...

..The K(+) channel blockers BaCl(2) (0.1, 1 mM) and tetraethylammonium (TEA; 30 mM) depolarized resting pericytes but did not affect membrane potential of ANG II-treated pericytes...

..We characterized membrane ionic currents underlying the action potential in single myocytes freshly isolated from the stroma of the guinea pig prostate...

..1 is an important component of beta-cell stimulus-secretion coupling, and a compound that enhances, but does not initiate, beta-cell electrical activity by acting on Kv2.1 would be a useful antidiabetic agent...

..fast activating and inactivating 4-aminopyridine-sensitive component and a slowly activating and maintained tetraethylammonium-sensitive component...

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..4-Aminopiridyne (4-AP) (10 mM) and tetraethylammonium (TEA) (100 mM) produced 98% and 92% reductions of I(Af) current, respectively and 27% and 66% of I(As) ..

..Thus, the currents were blocked by 4-aminopyridine, tetraethylammonium, verapamil, margatoxin, and charybdotoxin, with highly similar IC(50)s for given blockers...

..3 pA/pF. We suggest that the upregulation of voltage-gated time-dependently-inactivated K(+) currents and their faster recovery from inactivation serve to restrain the activity of glandular sympathetic neurons after decentralization...

..I(K,dr) was inhibited by clofilium, a blocker of voltage-gated K(+) channels, with an IC(50) of 12 micro M and was not blocked by 5 mM 4-aminopyridine. The possible significance of the voltage-gated currents is discussed...

..This suggests that a reduction of potassium currents may contribute to the antiepileptic effect(s) of levetiracetam...

..The IK(V) was blocked by tetraethylammonium ions with an IC50 of 5.2 mM and was unaffected by 1 mM 4-aminopyridine...

..To identify K+ channels of smooth muscle of human umbilical artery using the patch-clamp technique and to study their effect on resting tone of umbilical artery rings...

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..I(Kur) was resistant to tetraethylammonium, but sensitive to inhibition by 4-aminopyridine (4-AP) (IC(50) = 71.7 +/- 3.5 micromol/l)...

..Kv3 currents were differentiated from other tetraethylammonium-sensitive currents to establish their role in Purkinje cells under physiological conditions with current-..

..responsiveness of femoral arterial rings of 1-wk and 4-wk tail-suspended rats to potassium channel blockers, tetraethylammonium chloride (TEA) and 4-aminopyridine (4-AP), were recorded, and the currents of large conductance calcium-..

..Consistent with this, either increasing the external concentration of K+ or external application of tetraethylammonium caused a decrease in the rate of inactivation. Pharmacologically, XKv1...

..However, inhibition of the highly 4-AP- or DTX-I-sensitive component did not alter the rapidly inactivating nature of the firing pattern of the cells...

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..K(+) efflux from perfused bovine parotid tissues was not inhibited by a maxi-K(+) channel blocker, tetraethylammonium (TEA)...

..To investigate the role of endothelin-1 (ET-1) in the physiological and pathophysiological regulating mechanisms of voltage-gated K+ current (IKV) inhibition in rat intrapulmonary arterial smooth muscle cells (PASMCs)...

..The findings suggest a role for SNAP-25 in regulation of esophageal muscle cell excitability and contractility, and point to potential new targets for treatment of esophageal motor disorders...

..In the presence of tetraethylammonium (TEA) and 4-aminopyridine (4-AP), PACAP reduced a background K(+) current...

..to their inactivation time constants, relative amplitude, and response to K(+) channel blockers 4-AP and tetraethylammonium. The percentage (65%) of neurons displaying K(+) currents which were reduced to 30% in amplitude by 5 mM ..

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..I(A) in hair cells is also smaller in amplitude than in RPeD1 and is activated at more depolarized potentials. In like manner, I(KV) is smaller in hair cells and is activated at more depolarized potentials than in RPeD1...

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..The A-type current was insensitive to tetraethylammonium (TEA) at 1 mM, but was partially suppressed by higher concentrations (10 mM)...

..These results support the hypothesis that postnatal maturation of glomus cell O(2) sensitivity involves developmental regulation of the expression and/or O(2)-sensitivity of background ionic conductances...

..In the presence of tetraethylammonium (1mM), 5-HT caused Em depolarization similar to the control condition...

..the current had a transient component and a sustained component, which were blocked by 4-aminopyridine and tetraethylammonium, respectively; and both had a reversal potential of -66 mV, indicating that they were carried by K(+) ions...

..The mechanism underlying the different effects of SMF on the I(K,A) and I(K,V) inactivation was also discussed...

..05-50 mM), which inhibited the I(A) by 50%, was 0.7 mM. That for tetraethylammonium (TEA, 0.02-20 mM) to inhibit 50% of I(K) was 1.5 mM. In the current-clamp mode, we used 0...

..To investigate the potassium channel currents and response thereof to the blocker of potassium channel in epithelium of prostate of Sprague Dawley (SD) rats...

..Whole cell I(K(V)) were very sensitive to tetraethylammonium (TEA), as 1 mM TEA decreased the current amplitude by 32% while it took 10 mM 4-AP to decrease I(K(V)) by a ..

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..identified a voltage- and Ca(2+)-dependent 238 +/- 21-pS unitary K(+) currents that are inhibitable by tetraethylammonium (TEA, 1 mM) or iberiotoxin (100 nM)...

..Ramp-evoked current at subthreshold voltages was unaffected by 10 mM tetraethylammonium and likely represents I(A), because its voltage dependence overlaps that of I(A) activation (midpoint near -..

..b>Tetraethylammonium (TEA) is frequently used to inhibit delayed rectifier K(+) currents (I(DR)) during electrophysiological ..

..The voltage-dependent outward K+ currents were sensitive to tetraethylammonium (TEA; 10 mM) and 4-aminopyridine (4-AP; 2 mM)...

..Their activation might modulate the shape of sodium and calcium action potentials, their propagation along the dendrite, and thereby the electrotonic distance between the somatic and dendritic action potential initiation zones...

..5 mM 4-aminopyridine (4-AP). The sustained component was partially blocked by 2 mM tetraethylammonium (TEA)...

..The potassium channel blockers tetraethylammonium (TEA, 10 mM) and 4-aminopyridine (4-AP, 3 mM and 30 microM) reduced I(K), but only TEA attenuated the ..

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..The objectives of this proposal are to develop marketable, topical formulations of tetraethylammonium chloride (TEAC) for the treatment of human papillomavirus-induced common warts...

..Ethanol excitation is completely blocked by quinidine, but not by the other K channel blockers apamin, tetraethylammonium, barium or cesium...

..Ethanol excitation is completely blocked by quinidine, but not by the other K channel blockers apamin, tetraethylammonium, barium or cesium...

..Wall thickness was similar between groups. In a separate series of experiments, the contractile effect of tetraethylammonium (TEA; a KCa channel blocker) was determined in cerebral arteries from neonatal and adult mice...

..Wall thickness was similar between groups. In a separate series of experiments, the contractile effect of tetraethylammonium (TEA; a KCa channel blocker) was determined in cerebral arteries from neonatal and adult mice...

..Surprisingly the Kv2.1-/- islets remain sensitive to tetraethylammonium, a blocker of Kv channels and Ca2+-activated K+ channels (KCa)...

..Surprisingly the Kv2.1-/- islets remain sensitive to tetraethylammonium, a blocker of Kv channels and Ca2+-activated K+ channels (KCa)...

..Importantly, these studies will provide a view of the potential role of luminal events in drug-drug interactions and the development of nephrotoxicity, making it important work for improving overall health. ..

..The results of these studies will help predict and, ideally, preempt unwanted drug-drug interactions in both the kidney and liver, and can be expected to assist in development of programs of rational drug design. ..

..The results of these studies will help predict and, ideally, preempt unwanted drug-drug interactions in both the kidney and liver, and can be expected to assist in development of programs of structure-based rational drug design. ..

..The proposed studies will result in a new, general model of the cellular strategy for secretion of a diverse array of xenobiotic OAs, and a more specific understanding of the action of heavy metal chelators on renal cells. ..

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..Application of the information gained through these studies holds the promise of predicting potential drug-interactions and the basis of genetic differences in renal secretion of cationic xenobiotics. ..

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..These studies will define a novel therapeutic target for antihypertensive drug development based upon the mechanism(s) of Ca2+-Kv channel modulation. ..

..In addition, these studies will provide a new molecular target for genetic linkage studies in hypertension as well as new potential therapeutic targets. ..

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..The results from the experiments will be used to examine the mechanism and structural requirements in the ethanol-mediated modulation of the GABAA receptor function. ..

..The work described in this proposal will elucidate how these control mechanisms work and will enhance our understanding of how hypertension develops and impact how it is treated. ..

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..Changes in calcium cooperativity add a new facet to our thinking of synaptic plasticity. ..

..This project will increase the understanding of the importance process of NaCl reabsorption by epithelia, defects in which have been implicated in such diseases as cystic fibrosis, congestive heart failure and diarrhea...

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..It will be a great benefit to the public if an effective drug delivery system such as ocular iontophoresis can replace injections and systemic administration for drug delivery to the back of the eye. ..

..There will not be any significant change in the level of effort for key personnel in the next budget period. The estimated unobligated balance will not be greater than 25% of the current year's budget. ..

..In addition, the calculations are used to characterize various microscopic factors which cannot easily be accessed experimentally, but are essential for understanding the molecular determinants of channel function. ..

..The work described in this proposal will elucidate how these control mechanisms work and will enhance our understanding of how hypertension develops and impact how it is treated. ..

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..This latter will allow us to determine whether there is an actual mismatch between physiological and anatomical estimates of connectivity (i.e. non-functional synaptic connections). ..

..3 will be made and studied. The experiments will employ a range of techniques, including biochemical and electrophysiological assays in Xenopus oocytes and microsomal membranes of the endoplasmic reticulum. ..

..Our results will also advance the knowledge of the transport mechanisms and the barrier properties of the skin pathways during iontophoresis for future strategy development to enhance iontophoretic transport. ..

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..We will test whether DVR contractions to norepinephrine, Angll and KCI are increased, measure NO production and assess effects of OH on endothelial and pericyte Ca2+ signaling. ..