THE ACTION OF PROTRIPTYLINE ON PERIPHERAL AUTONOMIC FUNCTION

¹ Department of Pharmacology, University of Melbourne, Victoria, Australia

Protriptyline, a new tricyclie antidepressant agent, possesses a spectrum of pharmacological activity similar to that described for imipramine, amitriptyline and their desmethyl derivatives.

It would appear, however, that protriptyline possesses stronger anticholinergic actions than other antidepressants of this type.

Protriptyline does not reverse the pressor action of epinephrine. In this respect it is similar to imipramine and desipramine, but differs from amitriptyline and nortriptyline.

Protriptyline potentiates the peripheral actions of exogenous and endogenously released norepinephrine, and antagonizes the sympathomimetic effects of tyramine and guanethidine.

It was demonstrated that cocaine, in the conditions studied, does not antagonize the systemic effects of guanethidine.

If cocaine acts mainly on the surface of the cell membrane, and guanethidine has an intracellular action, the results described are consistent with the hypothesis that protriptyline has an intracellular action, in addition to a cocaine-like effect.