Characterization of endothelin 1 receptor and signal transduction mechanisms in rat medullary interstitial cells
| Autor: | E. P. Nord, B. M. Wilkes, D. Hart, R. Barnett, M. Vander Molen, E. P. Girardi, P. Mento, A. S. Ruston |
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| Rok vydání: | 1991 |
| Předmět: |
Agonist
medicine.medical_specialty Physiology medicine.drug_class Inositol Phosphates Receptors Cell Surface Biology Binding Competitive Dinoprostone chemistry.chemical_compound Phospholipase A2 Phosphoinositide Phospholipase C Nickel Internal medicine medicine Extracellular Animals Inositol phosphate Receptor Cells Cultured chemistry.chemical_classification Kidney Medulla Manganese Phospholipase C Phosphoric Diester Hydrolases Receptors Endothelin Endothelins Phosphatidylinositol Diacylglycerol-Lyase Inositol trisphosphate Rats Kinetics Endocrinology chemistry biology.protein Calcium Calcium Channels Endothelin receptor Signal Transduction |
| Zdroj: | The American journal of physiology. 260(4 Pt 2) |
| ISSN: | 0002-9513 |
| Popis: | Previous autoradiographic studies have delineated the renal medullas the predominant site of renal endothelin (ET) receptors. Accordingly, cultured rat renal medullary interstitial cells (RMICs) were studied as a target tissue for ET action. Scatchard analysis revealed presence of a single class of high-affinity receptor sites (Kd, 57 +/- 10 pM; receptor density, 749 +/- 124 fmol/mg protein). Relative potency order for displacing 125I-ET-1 was ET-1 greater than ET-2 greater than sarafotoxin greater than big endothelin (human) = big endothelin (porcine). ET-3, unrelated pressor substances, vasodilators, Ca2+ channel antagonists, atrial natriuretic factor, GTP, and GppNHp did not inhibit binding. Challenge of monolayers with ET-1 evoked a biphasic elevation in cytosolic free Ca2+ concentration [Ca2+]i). Initial transient rise in [Ca2+]i observed in absence of extracellular Ca2+ and accumulation of inositol trisphosphate (IP3) was consistent with activation of phosphatidylinositol-specific phospholipase C (PI-PLC). Half-maximal activation concentration of ET-1 for the process was 0.5 and 1 nM for [Ca2+]i and IP3, respectively. The late sustained phase in [Ca2+]i elevation was completely blocked by Ni2+, unperturbed by nimodipine, and accompanied by influx of Mn2+, indicating presence of receptor-operated Ca2+ channels. Ca2+ channel opening was detected at 10(-16) MET-1, whereas greater than 10(-12) M agonist was required to mobilize Ca2+ from intracellular stores and/or stimulate phosphoinositol hydrolysis, indicating that ET activation of PI-PLC and Ca2+ channel opening were independent events. ET-1 markedly stimulated prostaglandin E2 synthesis in a concentration-dependent manner that paralleled PI-PLC activation and mobilization of [Ca2+]i. In summary, cultured rat RMICs possess ET receptors that are linked to PI-PLC, Ca2+ channels, and perhaps phospholipase A2. |
| Databáze: | OpenAIRE |
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