Some Effects of Tranylcypromine and Trifluoperazine on Electrocortical Activity (EEG Activation)

In the deafferented cat devoid of the complicating effect of extraneous pharmacological agents (anaesthesia, muscle relaxants) the intra-innominate administration of tranylcypromine elicits immediate EEG activation. With high doses (7.5 mg/kg), EEG activation is immediate, intense, and persists for several hours. With lower doses (2.5 mg/kg) this effect is transient (20 seconds), giving way to a long period of deactivation (35–45 minutes), which in turn is followed by a secondary period of activation.

The immediate EEG activating response of tranylcypromine appears to be a direct effect, the secondary delayed phase of EEG activation appears to be an indirect action, such as might be expected from the retarded inactivation of central amines.

Trifluoperazine (2 mg/kg) elicits EEG deactivation with characteristics similar to those observed following the administration of “equi-deactivating” doses of chlorpromazine (5 mg/kg). When both trifluoperazine (2 mg/kg) and tranylcypromine (7.5 mg/kg) are introduced simultaneously, the activating effects of the latter dominate the earlier phases of the recording.

Preliminary experiments in some preparations in which gross unilateral lesions have been made in the mesencephalic tegmentum raises the possibility that this subcortical area may be a possible site for the arousal effect observed following the administration of tranylcypromine.

Narcotic antagonist activity of several metabolites of naloxone and naltrexone tested in morphine dependent mice (38558)

A rabbit liver enzyme system was used to produce the 6beta-OH reduced metabolites of naloxone and naltrexone. GC analysis indicated the presence of some 6alpha-OH metabolite in these samples. The narcotic antagonist activity of these 6beta-OH metabolite samples were compared to naloxone, naltrexone and standard 6alpha-OH naltrexone (EN-2260A) using the jumping response of morphine pellet implanted mice. For the naloxone series, the potencies were: Naloxone greater than EN 2265A greater than 6 beta-OH maloxone. For the naltrexone series: Naltrexone greater than EN 2260A greater than beta-OH naltrexone. The low potency of the reduced metabolites the rapid onset of action of the parent compounds militate against the formation of these metabolites contributing substantially to the overall narcotic antagonist action of the parent compounds.

Combined Tranylcypromine and Trifluoperazine Therapy in General Medicine

The tranylcypromine-trifluoperazine combination was used in several hundred patients in the past twenty months. It was tabulated in 26 cases for the purpose of this report. This evaluation is consistent with reported results of the use of the preparation in the treatment of emotional disorders where coexistent anxiety and depression are present. In my opinion, this drug combination is superior to any other psychopharmacological aid available for the treatment of the emotional disorders seen in my general practice.

Neuropharmacology of Tranylcypromine and Trifluoperazine

Tranylcypromine was compared to trifluoperazine in a number of pharmacological test procedures. Both compounds were effective in producing catalepsy, a selective blockade of the conditioned stimulus, and potentiation of hexobarbital-induced sleep. Unlike trifluoperazine, tranylcypromine was very effective as a tryptamine potentiator, a reflection of its activity as an in vivo inhibitor of the enzyme monoamine oxidase. Tranylcypromine was ineffective in producing any appreciable decrease in spontaneous motor activity at doses up to 20 mg/kg, whereas the DD50 for trifluoperazine was 1.1 mg/kg.