Article
Oxygen-sensitive calcium channels in vascular smooth muscle and their possible role in hypoxic arterial relaxation
Author/s | Franco Obregón, Alfredo
Ureña López, Juan López Barneo, José |
Department | Universidad de Sevilla. Departamento de Fisiología Médica y Biofísica |
Publication Date | 1995 |
Deposit Date | 2015-01-14 |
Published in |
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Abstract | We have investigated the modifications of cytosolic [Ca2+] and the activity of Ca2+ channels in freshly dispersed arterial myocytes to test whether lowering 02 tension (P02) directly influences Ca2+ homeostasis in these ... We have investigated the modifications of cytosolic [Ca2+] and the activity of Ca2+ channels in freshly dispersed arterial myocytes to test whether lowering 02 tension (P02) directly influences Ca2+ homeostasis in these cells. Unclamped cells loaded with fura-2 AM exhibit oscillations of cytosolic Ca22+ whose frequency depends on extracellular Ca2+ influx. Switching from a P02 of 150 to 20 mmHg leads to a reversible attenuation of the Ca2' oscillations. In voltage-clamped cells, hypoxia reversibly reduces the influx of Ca2+ through voltage-dependent channels, which can account for the inhibition of the Ca2+ oscillations. Low P02 selectively inhibits L-type Ca2' channel activity, whereas the current mediated by T-type channels is unaltered by hypoxia. The effect of low P02 on the L-type channels is markedly voltage dependent, being more apparent with moderate depolarizations. These findings demonstrate the existence of 02- sensitive, voltage-dependent, Ca2' channels in vascular smooth muscle that may critically contribute to the local regulation of circulation. |
Citation | Franco Obregón, A., Ureña López, J. y López Barneo, J. (1995). Oxygen-sensitive calcium channels in vascular smooth muscle and their possible role in hypoxic arterial relaxation. Proceedings of the National Academy of Sciences of the United States of America, 92 (10), 4715-4719. |
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