Varieties of Calcium-Activated Potassium Channels

Latorre, Ramón; Oberhauser, Andrés F.; Labarca, Pedro; Álvarez, Osvaldo

doi:10.1146/annurev.ph.51.030189.002125

Cited by 703 publications

(460 citation statements)

References 42 publications

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“…In addition, this odorant-triggered inhibitory conductance is sensitive to charybdotoxin (CTX), a toxin that blocks Ca 2+ -activated K+ channels [11]. In support of this notion, a CTX-sensitive Ca 2+ -activated K+ conductance has been recently reported to be present in toad olfactory cilia [12].…”

Section: Introductionmentioning

confidence: 90%

Calcium mediates the activation of the inhibitory current induced by odorants in toad olfactory receptor neurons

1997

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In toad olfactory neurons, a putrid odorant mixture inducing inhibitory responses increases Ca 2+ -activated K + conductance, developing a hyperpolarizing receptor potential. Removal of extracellular Ca 2+ or exposure to nifedipine reversibly reduced the inhibitory response, suggesting that odorants induce a Ca 2+ influx. We show evidence for an odorant-induced Ca 2+ current. Using confocal microscopy, it is shown that odorants induce a nifedipine-sensitive elevation of Ca 2+ in the apical end of the cell. These results suggest an inhibitory mechanism in which an apical Ca 2+ influx causes an increase in internal Ca 2+ , opening Ca 2+ -activated K 2+ channels that lead to membrane hyperpolarization.

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Section: Introductionmentioning

confidence: 90%

Calcium mediates the activation of the inhibitory current induced by odorants in toad olfactory receptor neurons

1997

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“…Channel activity was determined by the mean channel open probability (P o ), which was calculated as (1) where N is the number of maximally activated channels with [Ca 2ϩ ] i of 10 Ϫ3 M. t n (t 1 , t 2 , . .…”

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Modulation of the Ca2+-Activated Large Conductance K+ Channel by Intracellular pH in Human Renal Proximal Tubule Cells.

Hirano

Nakamura²,

Itazawa³

et al. 2002

JJP

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sensitive large conductance (big) K ϩ channels (BK channels) have been reported in the cell membranes of a variety of tissues [1,2]. An elevation of cytoplasmic Ca 2ϩ concentration ([Ca 2ϩ ] i ) and depolarization of the membrane commonly stimulates activity of the BK channels [1][2][3]. It has already been proved by the use of cloned BK channels that the channel protein possesses the Ca 2ϩ -binding sites [4,5] and the voltagesensing domain [6,7]. Besides Ca 2ϩ and voltage, other factors such as ATP [8-11], pH [8, 9, 12-21], and Mg 2ϩ [19,[22][23][24] were also reported to modulate BK channels. Among these factors, intracellular pH (pH i ) is one of the significant factors that affect channel activity [8,9,[12][13][14][15][16][17][18][19][20][21], i.e., channel activity is inhibited by intracellular acidification and stimulated by its alkalization. Although the mechanism for pH i effects on channel activity was not precisely understood, two different mechanisms have been proposed. One is that an increased cytoplasmic H ϩ can compete with Ca 2ϩ in binding to the same sites, thereby inhibiting channel activity [14][15][16], whereas the other is that the pH i -mediated change in channel activity is not competitive with Ca 2ϩ [17]. Moreover, it was demonstrated that the conductance of some BK channels was reduced by lowering pH i and enhanced by raising it [9,15,20].In the renal tubules, BK channels have been reported in cultured rabbit proximal tubule cells [25]

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“…Ca~"--activated K'-(K~'(Ca-~*)) channels were first identified in human erythrocytes [I] and are now known to be present in most cell types [2][3][4]. They show a wide range of single-channel conductances and differ in their dependence on Ca '~* and voltage.…”

Section: Introductionmentioning

confidence: 99%

Nitrendipine is a potent inhibitor of the Ca²⁺‐activated K⁺ channel of human erythrocytes

et al. 1992

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Nitrendipine, a classical blocker of L‐type Ca2+ channels, is shown to be a potent inhibitor of the Ca2+‐activated K+ channel of human erythrocytes. In erythrocytes suspended in a solution with physiological Na+ and K+ concentrations and in which the channel was activated using the Ca2+ ionophore ionomycin, nitrendipene inhibited K+(80Rb+) influx with an I 50 of around 130 nM. Similar results were obtained for K+(80Rb+) efflux, and for K+(80Rb+) influx into cells suspended in a high‐K+ medium.

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Varieties of Calcium-Activated Potassium Channels

Cited by 703 publications

References 42 publications

Calcium mediates the activation of the inhibitory current induced by odorants in toad olfactory receptor neurons

Calcium mediates the activation of the inhibitory current induced by odorants in toad olfactory receptor neurons

Modulation of the Ca2+-Activated Large Conductance K+ Channel by Intracellular pH in Human Renal Proximal Tubule Cells.

Nitrendipine is a potent inhibitor of the Ca²⁺‐activated K⁺ channel of human erythrocytes

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Varieties of Calcium-Activated Potassium Channels

Cited by 703 publications

References 42 publications

Calcium mediates the activation of the inhibitory current induced by odorants in toad olfactory receptor neurons

Calcium mediates the activation of the inhibitory current induced by odorants in toad olfactory receptor neurons

Modulation of the Ca2+-Activated Large Conductance K+ Channel by Intracellular pH in Human Renal Proximal Tubule Cells.

Nitrendipine is a potent inhibitor of the Ca2+‐activated K+ channel of human erythrocytes

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Nitrendipine is a potent inhibitor of the Ca²⁺‐activated K⁺ channel of human erythrocytes