Effect of p-chlorophenylalanine on avoidance learning of two differentially housed mouse strains.

The effect of p-chlorophenylalanine (PCPA) has been studied on the acquisition of avoidance learning and on brain concentrations of 5-hydroxytryptamine, 5-hydroxyindoleacetic acid and tryptophan of differentially housed male mice of Albino Swiss and DBA strains. The results obtained do not support the hypothesis that learning ability varies inversely with the concentration of brain 5-hydroxytryptamine. PCPA can appear as influencing learning ability of different strains of mice differentially housed, depending more on the emotional baseline of the animals than on brain 5-hydroxytryptamine modification.