Treatment with 0.5 mM Cd++ suppressed the K+ (30 mM)-stimulated uptake and influx of 45Ca and abolished the K+-induced contraction in helical strips of rabbit aortae. The rapid and slow efflux of 45Ca previously accumulated was not appreciably affected by Cd++. It is concluded that interference with the transmembrane influx of Ca++ is a major mechanism of Cd++ action.
