Dexfenfluramine increases pulmonary artery smooth muscle intracellular Ca2+, independent of membrane potential
| Autor: | Helen L. Reeve, Marjorie Soper, E. Kenneth Weir, Stephen L. Archer |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Male
Pulmonary and Respiratory Medicine medicine.medical_specialty Physiology Pulmonary Artery Muscle Smooth Vascular Calcium in biology Membrane Potentials Rats Sprague-Dawley Dexfenfluramine Physiology (medical) Internal medicine medicine.artery Appetite Depressants medicine Animals Anorexic agent Chemistry Electric Conductivity Intracellular Membranes Cell Biology medicine.disease Pulmonary hypertension Rats Endocrinology medicine.anatomical_structure Circulatory system Pulmonary artery Potassium Calcium Intracellular medicine.drug Blood vessel |
| Zdroj: | American Journal of Physiology-Lung Cellular and Molecular Physiology. 277:L662-L666 |
| ISSN: | 1522-1504 1040-0605 |
| Popis: | The anorexic agent dexfenfluramine causes the development of primary pulmonary hypertension in susceptible patients by an unknown mechanism that may include changes in K+-channel activity and intracellular Ca2+concentration ([Ca2+]i). We investigated the dose-dependent effects of dexfenfluramine on [Ca2+]i, K+current, and membrane potential in freshly dispersed rat pulmonary artery smooth muscle cells. Dexfenfluramine caused a dose-dependent (1–1,000 μM) increase in [Ca2+]i, even at concentrations lower than those necessary to inhibit K+currents (10 μM) and cause membrane depolarization (100 μM). The [Ca2+]iresponse to 1 and 10 μM dexfenfluramine was completely abolished by pretreatment of the cells with 0.1 μM thapsigargin, whereas the response to 100 μM dexfenfluramine was reduced. CoCl2(1 mM), removal of extracellular Ca2+, and pretreatment with caffeine (1 mM) reduced but did not abolish the response to 100 μM dexfenfluramine. We conclude that dexfenfluramine increases [Ca2+]iin rat pulmonary artery smooth muscle cells by both release of Ca2+from the sarcoplasmic reticulum and influx of extracellular Ca2+. |
| Databáze: | OpenAIRE |
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