Abstract
The Roborovskii hamster （P. roborovskii） has high locomotor activity （hyperactivity）and low dopamine levels in the brain compared with the congeneric Djungarian hamster （P. sungorus）. In the present study, we investigated the effects of acute administration of L-tyrosine, the primary precursor of dopamine, on the locomotor activity of and brain monoamine levels in Roborovskii hamsters to clarify the efficacy of L tyrosine in ameliorating signs of hyperactivity such as those observed in hyperactive dogs. Acute administration of L-tyrosine had no effect on locomotor activity in the open field, but increases in dopamine and norepinephrine turnover rates and decrease in serotonin turnover rate in the brain were observed. These findings suggest that acute feeding of L-tyrosine may be effective in modifying brain monoamine metabolism,but not ameliorating signs of hyperactivity in the Roborovskii hamster.
