Interaction of D 600 with phenoxybenzamine-induced adrenergic blockade.

Pretreatment of the vas deferens with D 600 (1 x 10(-5) M/10 min) prior to addition of phenoxybenzamine (PB) (1 x 10(-7) M/5 min) had no effect on the magnitude of initial adrenergic blockade but significantly increased the rate of recovery from blockade. These results suggest that the long duration of action of PB may be due to its action at calcium mobilization sites.