Concentrations of 4 trace amines in diencephalon and hippocampus of the rat were measured by integrated-ion-current mass spectrometry after administration of the antidepressant drug, tranylcypromine. Much larger increases were observed for 2-phenylethylamine and tryptamine than for m- and p-tyramine.

The effects of p-chloroamphetamine (pCA) on the regional distribution of dopamine, noradrenaline and 5-hydroxytryptamine in rat brain were studied at both 3 and 30 days after a single injection. It was found that pCA has no signifícant effect on the levels of dopamine or noradrenaline at either of the times studied. Conversely pCA had an effect on the levels of 5-hydroxytryptamine but the effect was both time and area dependent. pCA has been shown to be an effective antidepressant. Since the levels of 5-hydroxytryptamine were reduced in all areas studied and there was no effect on the levels of the two catecholamines, the results found in the study do not support an amine hypothesis in which these transmitters are implicated.

Solvent extraction of pooled rat brain stem tissues analyzed by a sensitive (long) TLC technique failed to identify 5-methoxytryptamine in these tissues. Since 5-methoxytrypamine has been suggested to be the identity of an unknown monoamine in rat brain this work cannot support this conjecture. Suggestion is made that this unknown amine could be tryptamine.

ECG changes occur with therapeutic doses of tricyclic antidepressants and cardiovascular conduction alteration is the lethal effect in overdoses on these drugs. These ECG changes depend on the plasma level and metabolism of the particular antidepressant. Information about the relative toxicity and metabolism characteristics can be obtained by studying overdoses if the attempt simply involves one tricyclic and no other drug ingestion. Such a case report involving a known quantity of imipramine is presented. The early toxic signs leading to cardiac arrest and the recovery from coma are discussed. The ECG along with corresponding plasma levels of imipramine and its metabolite desmethylimipramine are given as a function of time after ingestion. The relative toxicity of these metabolites and the use of anticholinesterase in the acute management is considered.