The effects of lithium on phenylethylamine behavior in rats are counteracted by monoamine oxidase A and B inhibitors.

Rats given a subcutaneous injection of beta-phenylethyl-amine (PEA) (30 or 60 mg/kg) showed stereotyped behavior and autonomic effects which were suppressed by LiCl. Inhibition of Type A MAO by clorgyline or Lilly 51641 (2 or 8 mg/kg) or of Type B MAO by l-deprenyl (2 or 8 mg/kg) counteracted the suppressant effects of LiCl on PEA-behavior. The findings suggest that both Type A MAO and Type B MAO play a role in the effects of LiCl on PEA-behavior.