the effect of oral administration of l-tyrosine, folic acid and pyridoxine on perphenazine induced catatonia in rat

l-tyrosine, b6 and folic acid are involved in biosynthesis of dopa and consequently dopamine. the aim of this study was to investigate the antiparkinsonian effect of these agents in perphenazine-induced catatonia in rats. murprogo method or scored muscular rigidity, which is induced by a phenothiazine, was used to evaluate the antiparkinsonian effect of these agents. a significant decrease in muscular rigidity was observed in groups that received l-tyrosine. however, groups which had received vitamin(s) only showed no significant decrease in muscular rigidity as compared with the control group. on the other hand, the group receiving folic acid plus l-tyrosine showed a lower degree of muscular rigidity in comparison with the other groups. in conclusion, l-tyrosine has been found to be effective in improving perphenazine-induced muscular rigidity. furthermore, when used in combination with folic acid, l-tyrosine could be found advantageous in the early stages of parkinson’s disease.