Activation of BKCa channel via endothelin ETA receptors in porcine coronary artery smooth muscle cells
| Autor: | Paula Savage, Helen S. Kim, Arco Y. Jeng, Shiling Hu |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
medicine.hormone
medicine.medical_specialty Potassium Channels Swine Biology Muscle Smooth Vascular Endothelins Potassium Channels Calcium-Activated Internal medicine medicine Animals Large-Conductance Calcium-Activated Potassium Channels Patch clamp Receptor education Pharmacology Endothelin-3 education.field_of_study Endothelin-1 Receptors Endothelin Coronary Vessels Endothelin 1 Potassium channel Endothelin 3 Endocrinology cardiovascular system Calcium medicine.symptom Endothelin receptor Muscle contraction |
| Zdroj: | European Journal of Pharmacology. 324:277-282 |
| ISSN: | 0014-2999 |
| DOI: | 10.1016/s0014-2999(97)00079-4 |
| Popis: | It has been demonstrated previously that endothelin-1 stimulates the Ca2+-activated K+ (BK(Ca)) channel activity in porcine coronary artery smooth muscle cells. The purpose of the present study was to delineate the endothelin receptor subtype involved in this action. In receptor binding studies, [125I]endothelin-1 was shown to bind to the homogenate of porcine primary coronary artery smooth muscle cells in a single class of binding sites with K(D) and Bmax values of 73 pM and 99 fmol/mg protein, respectively. Furthermore, endothelin-1 and endothelin-3 displaced the binding of [125I]endothelin-1 to these cells with respective IC50 values of 70 and 17000 pM, a 240-fold difference in potency. The effects of endothelin-3 on the activity of the BK(Ca) channel in porcine coronary artery smooth muscle cells were examined using the cell-attached patch-clamp technique. Similar to endothelin-1, endothelin-3 also exhibited a bell-shaped concentration-response curve. A maximal increase of 95% in channel open-state probability (Po) was induced by 100 nM endothelin-3 as compared with the 320% increase in Po by 1 nM endothelin-1. Thus, endothelin-1 was about 100-fold more potent and 3.4-fold more efficacious than endothelin-3 in this action. Both the receptor binding and the electrophysiological results suggest that the effects of endothelins on the BK(Ca) channel are mediated through the endothelin ET(A) receptor subtype. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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