Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Groschner, K; Kukovetz, WR.
Voltage-sensitive chloride channels of large conductance in the membrane of pig aortic endothelial cells.
Pflugers Arch. 1992; 421(2-3):209-217
Doi: 10.1007/BF00374829
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- Führende Autor*innen der Med Uni Graz
- Groschner Klaus
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- Abstract:
- Single, large-conductance chloride-selective channels were studied in the membrane of pig aortic endothelial cells. These channels were usually inactive in cell-attached recordings and activated spontaneously upon formation of inside-out patches or amphotericin B-perforated vesicles. Channel activity was voltage dependent, with a maximum open probability within the range of -20 mV to + 20 mV. Addition of 1 mM Zn2+ to either the cytoplasmic or extracellular side blocked channel activity reversibly. Extracellular 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS) blocked the channels; the concentration necessary for half-maximum blockade was 100 mumol/l. The frequency of observing channels in cell-attached patches increased from less than 5% to 27% when cells were treated for several minutes with 1 mumol/l bradykinin and to 80% in the presence of the calcium ionophore A23187 (1 mumol/l). Both agents increase the cytoplasmic Ca2+ concentration, thereby stimulating nitric oxide (NO) synthesis and cGMP formation in endothelial cells. Sodium nitroprusside (100 mumol/l), which spontaneously releases NO, did not increase Cl- channel activity in intact cells. Polymyxin B (100 mumol/l), an inhibitor of protein kinase C, clearly enhanced Cl- channel activity in intact cells, resulting in the observation of Cl- channels in 70% of cell-attached patches. Our results demonstrate the existence of a large-conductance (LC-type) Cl- channel in vascular endothelium which is subject to a complex cellular regulation, possibly involving inhibition via phosphorylation by protein kinase C, and activation by a Ca2(+)-dependent process which is different from the NO/cGMP pathway.
- Find related publications in this database (using NLM MeSH Indexing)
- Amphotericin B - pharmacology
- Animals -
- Calcium - metabolism
- Chlorides - metabolism
- Cytoplasm - drug effects Cytoplasm - metabolism
- Electrophysiology -
- Endothelium, Vascular - cytology Endothelium, Vascular - metabolism
- Ion Channels - metabolism
- Membrane Potentials - physiology
- Membranes - metabolism
- Protein Kinase C - metabolism
- Swine -
- Zinc - pharmacology
- Find related publications in this database (Keywords)
- ENDOTHELIAL CELLS
- CHLORIDE CHANNEL
- PATCH CLAMP
- PERFORATED VESICLES
- DIDS
- ZN2+ IONS
- CELLULAR REGULATION