[Effect of transmembrane potential on noradrenaline transport in chromaffin granules]

Imposing a transmembrane potential positive with respect to the medium on chromaffin granule ghosts increased the initial rate of the delta pH-induced uptake of noradrenaline, whereas imposing a negative potential decreased this rate. The increase of the uptake rate was proportional to the potential. The ATP-induced uptake of noradrenaline was also sensitive to the potential since imposing a transient negative potential onto the positive potential generated by the membrane ATPase induced a latency in this transport.