Effects of alpha methyltyrosine and parachlorophenylalanine on open field behavior in rats given tranylcypromine stereoisomers and lithium carbonate.

Parachlorophenylalanine (PCPA) and alpha methyltyrosine (AMT) were used to study the roles of serotonin and catecholamines in hyperactivity produced by the stereoisomers of Tranylcypromine (d-Tc and 1-Tc) in male Wistar rats fed a normal diet (control groups) or a diet containing lithium carbonate (lithium groups). Components of locomotor activity were measured in an open field. Lithium decreased ambulation. d-Tc increased ambulation and caused jerky side-to-side movements. PCPA and AMT prevented the effects of d-Tc on ambulation while only PCPA prevented the effects of d-Tc on movement. 1-Tc increased ambulation. The effects of 1-Tc on ambulation were potentiated by PCPA and prevented by AMT. Rearing was increased by 1-Tc and d-Tc in rats given lithium. PCPA and AMT prevented the effects of 1-Tc and d-Tc on rearing in lithium groups. The findings suggest that the roles of serotoninergic and catecholaminergic mechanisms differ for components of open field behavior in control rats and rats given lithium.