Noradrenaline augments tetanic potentiation of transmitter release by a calcium dependent process

Noradrenaline (25 microM-50 microM) causes an increase in tetanic potentiation and in the augmentation phase of posttetanic potentiation of miniature and plate potential frequency. These effects were observed at both the frog and the rat neuromuscular junctions. The action of noradrenaline on quantal transmitter release depends on the presence of calcium ions in the extracellular medium.