Abstract
The patch-clamp technique was used to examine the presence of large conductance calcium-activated potassium channels (BKCa) in human endothelial cells and to characterize their properties in terms of voltage dependence, ion conduction and blockade by iberiotoxin (IbTX). Experiments were performed using cell-attached and outside-out configurations on human umbilical vein endothelial cells (HUVEC). For the experiments HUVECs, which were passaged 6–19 times, were used. In early passages channel activities were absent suggesting the appearance of BKCa depending on cell culture time. The inverse logarithmic voltage sensitivity was 10.17 mV (median) for cell-attached recordings and 12.10 mV (median) for outside-out patches (membrane voltage range: 60–120 mV, symmetrical 140 mM K+ solutions). The I/V relationship was quasilinear in the range of 0–80 mV and exhibited a nonlinear behaviour under further depolarization suggesting some kind of saturation mechanism. Using a sigmoid function to fit the data, channel conductance was calculated as 172.9 pS (median) for cell-attached patches and as 262.1 pS (median) for outside-out patches. IbTX, known as one of the most selective blockers of BKCa was perfused to outside-out patches. In two out of three experiments there was complete block of the ion channel after 1 min.
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References
Barrett J, Magleby KL, Pallotta B (1983) Properties of single calcium?activated potassium channels in cultured rat muscle. J Physiol 344:585–604
Berridge M (1995) Calcium signalling and cell proliferation. BioEssays 17(6):491–500
Blatz A, Magleby K (1984) Ion conductance and selectivity of single calcium?activated potassium channels in cultured rat muscle. J Gen Physiol 84:1–23
Blatz A, Magleby KL (1987) Calcium?activated potassium channels. TINS 10(11):463–467
Candia S, Garcia M, Latorre R (1992) Mode of action of iberiotoxin, a potent blocker of the large conductance Ca2+ activated K+ channel. Biophys J 63:583–590
Colden-Stanfield M, Schilling W, Possani L, Kunze D (1990) Bradykinin-induced potassium current in cultured bovine aortic endothelial cells. J Membr Biol 116(3):227–238
Daut J, Standen N, Nelson M (1994) The role of the membrane potential of endothelial and smooth muscle cells in the regulation of coronary blood flow. J Cardiovasc Electrophysiol 5(2)155–181
Demirel E, Rusko J, Laskey R, Adams D, Breemen C van (1994) TEA inhibits ACh-induced EDRF release:endothelial Ca2+-dependent K+ channels contribute to vascular tone. Am J Physiol 267(3):H1135–H1141
Deutsch C, Price M, Lee S, King V, Garcia M (1991) Characterization of high affinity binding sites for charybdotoxin in human T lymphocytes. J Biol Chem 266:3668–3674
Fichtner HU, Froebe RB, Kohlhardt M (1987) Single nonselective cation channels and Ca2+-activated k+ channels in aortic endothelial cells. J Membr Biol 98:125–133
Gallin E, McKinney L (1988) Patch-clamp studies in human macrophages:single-channel and whole-cell characterization of two K+ conductances. J Membr Biol 103(1)55–66
Giangiacomo K, Garcia M, McManus O (1992) Mechanism of iberiotoxin block of the large?conductance calcium?activated potassium channel from bovine aortic smooth muscle. Biochemistry 31:6719–6727
Groschner K, Graier W, Kukovetz W (1992) Activation of a small?conductance Ca2+-dependent K+ channel contributes to bradykinin?induced stimulation of nitric oxide synthesis in pig aortic endothelial cells. Biochim Biophys Acta 1137(2)162–170
Hamill O, Marty A, Neher E, Sakmann B, Sigworth F (1981) Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflügers Arch 391:85–100
Hille B (ed) (1992) Ionic channels of exitable membranes, 2 edn. Sinauer Associates, Sunderland, Mass
Hoyer J, Distler A, Haase W, Goegelein H (1994) Ca2+ influx through stretch?activated cation channels activates maxi K+ channels in porcine endocardial endothelium. Proc Natl Acad Sci 91(6):2367–2371
Jaffe E, Nachman R, Becker C, Minick C (1973) Culture of human endothelial cells derived from umibilical veins. J Clin Invest 52:2745
Kolb H (1990) Potassium channels in excitable and non-excitable cells. Rev Physiol Biochem Pharmacol 115:51–91
Latorre R, Oberhauser A, Labarca P, Alvarez O (1989) Varieties of calcium?activated potassium channels. Ann Rev Physiol 51:385–399
Leonard R, Garcia M, Slaughter R, Reuben J (1992) Selective blockers of voltage?gated K+ channels depolarize human T lymphocytes:mechanism of the antiproliferative effect of charybdotoxin. Proc Natl Acad Sci USA 89:10094–10098
Luckhoff A, Busse R (1990) Calcium influx into endothelial cells and formation of endothelium-derived relaxing factor is controlled by the membrane potential. Pflügers Arch 416(3):305–311
Magleby KL, Pallotta B (1983) Burst kinetics of single calcium?activated potassium channels in cultured rat muscle. J Physiol 344:602–623
Magleby KL, Pallotta B (1983) Calcium dependence of open and shut interval distributions from calcium?activated potassium channels in cultured rat muscle. J Physiol 344:585–604
Manabe K, Ito H, Matsuda H, Noma A, Shibata Y (1995) Classification of ion channels in the luminal and abluminal membranes of guineapig endocardial endothelial cells. J Physiol 484:41–52
Marty A (1981) Ca-dependent K channels with large unitary conductance in chromaffin cell membranes. Nature (London) 291:497–500
Methfessel C, Boheim G (1982) The gating of single calcium-dependent potassium channels is described by an activation/blockade mechanism. Biophys Struct Mech 9:35–60
Moczydlowski E, Latorre R (1983) Gating kinetics of Ca2+-activated K+ channels from rat muscle incorporated into planar lipid bilayers. J Gen Physiol 82:511–542
Nilius B, Riemann D (1990) Ion channels in human endothelial cells. Gen Physiol Biophys 9(2):89–111
Perry P, O’Neill W (1994) Swelling?activated K+ fluxes in vascular endothelial cells:role of intracellular Ca2+. Am J Physiol 267(6)C1535–C1542
Petersen O, Maruyama Y (1984) Calcium?activated potassium channels and their role in secretion. Nature 307:693–696
Ross R (1993) The pathogenesis of atherosclerosis:a perspective for the 1990s. Nature 362:801–809
Rusko J, Tanzi F, Breemen C van, Adams D (1992) Calcium?activated potassium channels in native endothelial cells from rabbit aorta:conductance, Ca2+ sensitivity and block. J Physiol 455:601–621
Sakai T (1990) Acetylcholine induces Cadependent K currents in rabbit endothelial cells. Jpn J Pharmacol 53(2)235–246
Sauvé R, Parent L, Simoneau C, Roy G (1988) External ATP triggers a biphasic activation process of a calcium-dependent K+ channel in cultured bovine aortic endothelial cells. Pflügers Arch 412(5):469–481
Sauvé R, Chahine M, Tremblay J, Hamet P (1990) Single-channel analysis of the electrical response of bovine aortic endothelial cells to bradykinin stimulation:contribution of a Ca2+-dependent K+ channel. J Hypertension 8 [Suppl 7]:S193–S201
Singer JJ, Walsh JV, Jr (1987) Characterization of calcium-activated potassium channels in single smooth muscle cells using the patch-clamp technique. Pflügers Arch 408(2):98–111
Soltoff S, Cantley L (1988) Mitogens and ion fluxes. Ann Rev Physiol 50:207–223
Takeda K, Klepper M (1990) Voltage-dependent and agonist-activated ionic currents in vascular endothelial cells:a review. Blood vessels 27:169–183
Vázquez J, Feigenbaum P, King V, Kaczorowski G, Garcia M (1990) Characterization of high affinity binding sites for charybdotoxin in synaptic plasma membranes from rat brain. J Biol Chem 265:15564–15571
Vergara C, Latorre R (1983) Kinetics of Ca2+-activated K+ channels from rabbit muscle incorporated into planar bilayers. Evidence for a Ca2+ and Ba2+ blockade. J Gen Physiol 82:543–568
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Kestler, H.A., Janko, S., Häußler, U. et al. A remark on the high-conductance calcium-activated potassium channel in human endothelial cells. Res. Exp. Med. 198, 133–143 (1998). https://doi.org/10.1007/s004330050097
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DOI: https://doi.org/10.1007/s004330050097