Noradrenaline contracts arteries by activating voltage-dependent calcium channels

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作者：

MT Nelson，NB Standen，JE Brayden，JF Worley

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摘要：

Noradrenaline (NA) regulates arterial smooth muscle tone and hence blood vessel diameter and blood flow 1 . NA apparently increases tone by causing a calcium influx through the cell membrane 1–3 . Two calcium influx pathways have been proposed: voltage-activated calcium channels and NA-activated calcium-permeable channels that are voltage-insensitive 1 . Although voltage-activated calcium channels have been identified in arterial smooth muscle 4, 5 , voltage-insensitive calcium channels activated by NA have not. We show here that NA contractions of rabbit mesenteric arteries increase with depolarization. The increase parallels the elevation of open-state probability ( P ) of single, voltage-dependent calcium channels. The action of noradrenaline can be explained by NA-activating voltage-dependent calcium channels, rather than by opening a second type of channel. We show directly that N A increases the open-state probability of single calcium channels. Thus, in the presence of NA, calcium entry through voltage-dependent calcium channels can regulate smooth muscle tone at physiological membrane potentials. These results may have relevance to pathophysiological conditions such as hypertension.

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DOI：

10.1038/336382a0

被引量：

780

年份：

1988