Intracellular cAMP involvement in the synchronized activity of noradrenaline in response to evoked release of the transmitter quanta in the frog synapses

An analogue of cyclic AMP (db-cAMP) penetrating into the frog neuromuscular junction's cell, as well as the adenylyl cyclase activator forskolin, and inhibitor of nucleotide-depending phosphodiesterase isobutilmethylxantine alter the kinetics of the quanta secretion resulting in synchronizing of the process of the transmitter release. Following a db-cAMP preliminary action, no such synchronizing of the transmitter release occurred. Action of noradrenaline on the time course of the secretion seems to be realised through activation of presynaptic beta-adrenoreceptors, augmentation of the adenylyl cyclase activity, and the rise of the intracellular cAMP.