Noradrenaline release and uptake in isolated small dense cored vesicles from rat seminal ducts

Noradrenaline (NA) release and uptake was investigated in an improved preparation of isolated small dense cored vesicles from rat seminal ducts. The vesicle preparation exhibited an Mg2+-ATP-dependent uptake of NA. Half maximal uptake after 20 min was seen at 22 muM. Exchangeability of NA between medium and vesicles was 100%. The kinetics of exchange suggested that mos NA is stored in a single pool. The t1/2 for release of NA was 43 min in the presence of Mg2+-ATP, as compared to 15 min in the absence of Mg2+-ATP. Addition of reserpine (20 muM) did not significantly alter the NA release. The kinetic properties of this preparation was compared to those of earlier reported noradrenergic vesicle preparations from different tissues.