| || Modulatory Effects of L Tyrosine on Neurobehavioural Consequences of Combat Stress in Rats
Author : Satija, Narinder K. ;Vij, Anjana G.
Source : Defence Science Journal ; Vol:48(2) ; 1998 ; pp 149-154
Subject : 57.089 Biomedical Sciences ;61 Medical Sciences;612 Physiology
Keywords : Post stress performance ;Monoamine oxidase;Saline injected rats;Morris water maze;Catecholaminergic neurotransmitters
Abstract : The paper presents the results of a study conducted to elucidate the potentiality of tyrosine, a precursor of catecholaminergic neurotransmitters, against combat stress-associated behavioural changes and brain catecholamine status in an animal model. The results obtained showed that stress impaired the performance on Morris water maze (MWM) in saline-injected rats and concurrently lowered norepinephrine (NE) levels in brain. This could be due to decreased dopamine Beeta-hydroxylase (DBH) activity and increased monoamine oxidase (MAO) activity. On the contrary, there was a significant improvement in post-stress performance in MWM test in animals receiving tyrosine. Stress-induced increase in catecholamine metabolites, homovanillic acid and vanillylmandelic acid in brain was prevented by treatment with tyrosine. The present findings imply that precursor availability could be a limiting factor to sustain intensified catecholamine synthesis during stress and hence supplementation of L-tyrosine could be beneficial to improve performance during stress.