Regional 5-HT analysis in Roman high- and low-avoidance rats following MAO inhibition.

5-HT and 5-HIAA levels were investigated in three brain regions of Roman high- and low-avoidance rats, following 10, 30 and 60 min of MAO inhibition (pargyline injection). Higher levels of 5-HT in the cortex at 30 and 60 min, as well as a higher disappearance rate of 5-HIAA in the midbrain/medulla region were exhibited by Roman high-avoidance rats, thus further characterizing the differences previously observed in whole brain 5-HT synthesis between these selected rat lines.