FOSCARNET INHIBITS VASCULAR SMOOTH-MUSCLE CONTRACTION

Foscarnet inhibited noradrenaline and calcium-mediated contractions of the isolated perfused tail artery of the rat. When the noradrenaline contractile response was split into two components, where the first was due to the release of calcium from intracellular stores and the second to the influx of calcium from the extracellular fluid, foscarnet (30 muM) inhibited only the first component of the response. Foscarnet did not inhibit the calcium influx component of the noradrenaline contraction, nor did it affect the inhibition of this component by the L-type calcium channel antagonists verapamil and nicardipine. These results indicate that foscarnet inhibits vascular smooth muscle contraction by inhibiting calcium release from intracellular stores.