Modulatory Effects of L- Tyrosine on Neurobehavioural Consequences of Combat Stress in Rats
AbstractThe paper presents the results of a study conducted to elucidate tile potentiality of tyrosine, aprecursor of catecholaminergic neurotransmitters, against combat stress-associated behavioural changes and brain catecholamine status in an animal model. The results obtained showed that stressimpaired the performance on Morris water maze (MWM) in saline-injected rats and concurrentlylowered norepinephrine (NE) levels in brain. This could be due to decreased dopamine J3-hydroxylase(DBH) activity and increased monoamine oxidase (MAO) activity. On the contrary, there was asignificant improvement in post-stress performance in MWM test in animals receiving tyrosine.Stress-induced increase in catecholamine metabolites, homovanillic acid and vanillylmandelic acid inbrain was prevented by treatment with tyrosine. The present fmdings imply that precursor availabilitycould be a limiting factor to sustain intensified catecholamine synthesis during stress and hencesupplementation of L-tyrosine could be beneficial to improve performance during stress
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