Ca2+ entry and vasoconstriction during osmotic swelling of vascular smooth muscle cells
| Autor: | Günther Zempel, Helmut Heinle, Ute Emerich, Horst Apfel, Florian Lang, Dorothee Axel, Peter Krippeit-Drews, Sabine Meierkord, Matthias Hoch, Jürgen Fingerle, Gillian L. Busch, Jens Ditlevsen |
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| Rok vydání: | 1995 |
| Předmět: |
Vascular smooth muscle
Patch-Clamp Techniques Physiology Clinical Biochemistry Guinea Pigs Aorta Thoracic In Vitro Techniques Muscle Smooth Vascular Membrane Potentials Physiology (medical) Extracellular fluid medicine Animals Humans Channel blocker Patch clamp Cells Cultured Cell Size Chemistry Osmolar Concentration Depolarization Hydrogen-Ion Concentration Electrophysiology Biochemistry Hypotonic Solutions Vasoconstriction Muscle Tonus Biophysics Tonicity Calcium Channels medicine.symptom Fura-2 Intracellular |
| Zdroj: | Pflugers Archiv : European journal of physiology. 431(2) |
| ISSN: | 0031-6768 |
| Popis: | Exposure of aortic strips from guinea-pigs to hypotonic extracellular fluid is followed by marked vasoconstriction, which is inhibited by D-600 (3 microM), a blocker of voltage-sensitive Ca2+ channels. Conventional electrophysiology, patch-clamp studies, pH determination with 2',7' bis(2-carboxyethyl)-5,6-carboxyfluorescein (BCECF) and Ca2+ measurements with Fura-2 have been performed on smooth muscle cells cultured either from rat or human aorta to further elucidate the underlying mechanisms. Exposure of the cells to a 25% hypotonic extracellular fluid leads to a rapid and fully reversible depolarization, paralleled by an increase of the selectivity and conductance of the cell membrane to Cl-, an acidification of the cytoplasm and an increase of intracellular Ca2+ concentration ([Ca2+]i). The latter is inhibited by the Ca2+ channel blocker D-600 (1-3 microM). It is concluded that osmotic cell swelling leads to the activation of an anion channel. The subsequent depolarization of the cell membrane activates voltage-sensitive Ca2+ channels which increases [Ca2+]i, thus stimulating the contraction of vascular smooth muscle cells. |
| Databáze: | OpenAIRE |
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