The effect of monoamine oxidase inhibitors on the rectal temperature of the rat

The monoamine oxidase (MAO) inhibitors, clorgyline, harmaline, nialamide, phenelzine and tranylcypromine, injected intraperitoneally into conscious unrestrained rats produced hypothermia. When clorgyline and tranylcypromine were compared, the latter produced a larger degree of hypothermia in spite of the fact that both drugs almost completely inhibited liver and hypothalamic MAO. Hypothermia produced by tranylcypromine, but not that produced by clorgyline, was attenuated by prior administration of haloperidol which indicated that it was partly mediated by a dopaminergic mechanism. In addition, tranylcypromine, but not clorgyline, inhibited uptake of (–)‐noradrenaline into rat hearts. Hypoglycaemia was not involved in the hypothermia produced by these MAO inhibitors in rats. 1974 Royal Pharmaceutical Society of Great Britain