Rats pretreated with
tranylcypromine and given
clomipramine, developed head and body twitches, forelimb flexor-extensor movements and wet dog shakes, phenomena which failed to develop when pretreatment incorporated
p-chlorophenylalanine (PCPA) but were unabated when this included
alpha-methyl-p-tyrosine (AMPT). Locomotor activity, itself enhanced by
tranylcypromine, was further and significantly elevated compared to saline, by
clomipramine or
imipramine in grouped rats (n = 3) but not in single or paired rats;
desipramine lacked such action. This effect of
clomipramine was prevented when PCPA was incorporated into the pretreatment and that of
imipramine by including PCPA or AMPT. Brain
monoamine oxidase (
MAO) A inhibition was 92% and that of
MAO B, 80%. Cortical
hydroxytryptamine (5-HT) and
noradrenaline concentrations as well as hypothalamic
5-HT, were significantly elevated by
tranylcypromine, as was
dopamine in the striatum, nucleus accumbens and tuberculum olfactorium.
Hyperthermia developed in
tranylcypromine pretreated rats given
paroxetine or
fluoxetine. Myoclonic phenomena were elicited by
paroxetine,
fluoxetine,
clomipramine or
imipramine in
nialamide pretreated rats but these were less intense than in rats pretreated with
phenelzine or
tranylcypromine. Fatalities were fewer than in rats pretreated with
tranylcypromine or
phenelzine. Brain
MAO A inhibition was 92% and that of
MAO B, 69%.