A glibenclamide sensitive potassium conductance in terminal arterioles isolated from guinea pig heart

Klieber, Hans-Georg; Daut, Jürgen

doi:10.1093/cvr/28.6.823

Cited by 25 publications

(30 citation statements)

References 4 publications

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“…4). This value is consistent with the slope factors of 5-10 mV reported for strong inwardly rectifying K+ channels in other tissues (Hille, 1992) and with the chord conductance-voltage relationship determined by Silver & DeCoursey (1990) (Olesen & Bundgaard, 1993 Beny, 1993;Beny & Pacicca, 1994;Klieber & Daut, 1994). Thus our data support the hypothesis that potential changes in capillary endothelial cells, induced by local release of vasoactive substances, could lead to changes in the tone of the feeding arteriole .…”

Section: Cell Isolationsupporting

confidence: 92%

“…Isolated guinea-pig hearts from animals weighing 250-350 g were enzymatically dispersed by a modification of a procedure described previously (Klieber & Daut, 1994). After decapitation the hearts were rapidly excised and perfused with oxygenated physiological salt solution at a constant flow rate of 10 ml min-.…”

Section: Cell Isolationmentioning

confidence: 99%

“…Isolated vascular smooth muscle cells can be identified morphologically. Nevertheless, we applied some electrophysiological tests to make sure that we were not recording from (possibly hypercontracted) vascular smooth muscle cells, which also show inward rectification (Klieber & Daut, 1994). In twelve spherical cells showing the typical strong inward rectification we applied 2 /SM levrocromakalim.…”

Section: Cell Isolationmentioning

confidence: 99%

“…In none of these cells did the drug affect the I-Vrelationship. In previous studies we have shown that cromakalim can activate a K+ conductance in vascular smooth muscle cells ( Klieber & Daut, 1994), whereas coronary endothelial cells are unresponsive to this drug (Mehrke, Pohl & Daut, 1991 In order to get some information about the I-V relationship in the absence of the leak component a procedure similar to the one used by Standen & Stanfield (1978) was employed, as illustrated in Fig. 3.…”

Section: Cell Isolationmentioning

confidence: 99%

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Inwardly rectifying K+ channels in freshly dissociated coronary endothelial cells from guinea‐pig heart.

Beckerath

Dittrich

Klieber

et al. 1996

The Journal of Physiology

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1. Inwardly rectifying K+ ('K(IR)) currents of freshly dissociated coronary endothelial cells from guinea-pig heart were investigated with the perforated-patch technique. 2. The whole-cell current-voltage relationship of endothelial cells showed strong inward rectification. Increasing the extracellular K+ resulted in an increase of inward currents. The slope conductance of the cells in the potential range negative to the calculated potassium equilibrium potential (EK) with 5, 60 and 150 mm external potassium was 0-18 + 0'14, 0.55 + 0 50 and 0-63 + 0-29 nS (mean + S.D.), respectively. 3. To quantify the steepness of inward rectification, the voltage dependence of the chord conductance of the cells was fitted with a Boltzmann function. The slope factor k describing the steepness of the relationship was 6-8 + 1'5 mV. 4. Extracellular barium induced a potential-and time-dependent block of inward currents through endothelial KIR channels. Half-maximum inhibition of IK(IR) currents was achieved with < 1 AM barium at a membrane potential of -70 mV in a solution containing 60 mM K+.5. Whole-cell inward currents revealed the opening and closing of single KIR channels. The single-channel conductance was 26 + 3 pS with 60 mm external K+ and 33 + 6 pS with 150 mm external K+. 6. Our results suggest that the electrical properties of freshly dissociated endothelial cells are to a large extent determined by five to sixty active strong inwardly rectifying K+ (KIR) channels.

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Section: Cell Isolationsupporting

confidence: 92%

Section: Cell Isolationmentioning

confidence: 99%

Section: Cell Isolationmentioning

confidence: 99%

Section: Cell Isolationmentioning

confidence: 99%

See 2 more Smart Citations

Inwardly rectifying K+ channels in freshly dissociated coronary endothelial cells from guinea‐pig heart.

Beckerath

Dittrich

Klieber

et al. 1996

The Journal of Physiology

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“…Large diameter coronary arteries express several types of potassium channel, including voltage-activated potassium (Kv) channels, calcium-activated potassium channels, and ATP-sensitive potassium channels (Toro, Vaca & Stefani, 1991;Volk, Matsuda & Shibata, 1991;Ishikawa, Hume & Keef, 1993;Dart & Standen, 1993). More recently, preliminary reports have identified inward rectifier potassium (KIR) channels in small diameter coronary arteries or arterioles (Bonev, Robertson & Nelson, 1994;Klieber & Daut, 1994;Quayle, Dart & Standen, 1995).…”

mentioning

confidence: 99%

The properties and distribution of inward rectifier potassium currents in pig coronary arterial smooth muscle.

Quayle

Dart

Standen

1996

The Journal of Physiology

136

124

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1. Whole-cell potassium currents were studied in single smooth muscle cells enzymatically isolated from pig coronary arteries. 2. In cells isolated from small diameter branches of the left anterior descending coronary artery (LAD), an inward rectifier potassium current (IK(IR)) was identified, which was inhibited by extracellular barium ions, suggesting the presence of inward rectifier potassium (KIR) channels.3. The conductance for IK(IR) measured in 6, 12, 60 and 140 mm extracellular potassium was a function of membrane potential and the extracellular potassium concentration. 4. On hyperpolarization, IK(IR) activated along an exponential time course with a time constant that was voltage dependent. 5. Inward rectifier current was compared in cells isolated from coronary vessels taken from different points along the vascular tree. Current density was greater in cells isolated from small diameter coronary arteries; at -140 mV it was -20f5 + 4f4 pA pF-' (n = 23) in 4th order branches of the LAD, but -0 8 + 0 2 pA pF-' (n = 11) in the LAD itself.6. In contrast to 'K(IR)' there was little effect of arterial diameter on the density of voltagedependent potassium current; densities at +30 mV were 12 8 + 1 3 pA pF-' (n = 19) in 4th order branches and 17 4 + 3 1 pA pF-' (n = 11) in the LAD.7. We conclude that KIR channels are present in pig coronary arteries, and that they are expressed at a higher density in small diameter arteries. The presence of an enhanced IK(IR) may have functional consequences for the regulation of cell membrane potential and tone in small coronary arteries.

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Regulation of Coronary Blood Flow

Goodwill

Dick

Kiel

et al. 2017

Comprehensive Physiology

244

248

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The heart is uniquely responsible for providing its own blood supply through the coronary circulation. Regulation of coronary blood flow is quite complex and, after over 100 years of dedicated research, is understood to be dictated through multiple mechanisms that include extravascular compressive forces (tissue pressure), coronary perfusion pressure, myogenic, local metabolic, endothelial as well as neural and hormonal influences. While each of these determinants can have profound influence over myocardial perfusion, largely through effects on end-effector ion channels, these mechanisms collectively modulate coronary vascular resistance and act to ensure that the myocardial requirements for oxygen and substrates are adequately provided by the coronary circulation. The purpose of this series of Comprehensive Physiology is to highlight current knowledge regarding the physiologic regulation of coronary blood flow, with emphasis on functional anatomy and the interplay between the physical and biological determinants of myocardial oxygen delivery.

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A glibenclamide sensitive potassium conductance in terminal arterioles isolated from guinea pig heart

Cited by 25 publications

References 4 publications

Inwardly rectifying K+ channels in freshly dissociated coronary endothelial cells from guinea‐pig heart.

Inwardly rectifying K+ channels in freshly dissociated coronary endothelial cells from guinea‐pig heart.

The properties and distribution of inward rectifier potassium currents in pig coronary arterial smooth muscle.

Regulation of Coronary Blood Flow

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