[Postsynaptic attack of tricyclic antidepressive agents in the circulatory system]

Tricyclic antidepressives (TA) exert differential effects on the circulatory system, though all of them have one principle in common: inhibition of back resorption of noradrenaline in the adrenergic synapses. Of more importance, however, seems to be the dose rather than the type of substance used. Smaller doses were found to potentiate the pressoric effects of noradrenaline, while higher doses frequently had an inhibitory action. In rats pretreated with 6-OH-dopamine, only an inhibitory action has been established. It is concluded that the TA must have a postsynaptic influence that becomes effective either through the membrane receptors and/or other factors within the cell.