Tsakiris_2000_Clin.Biochem_33_103

OBJECTIVE: To investigate whether the preincubation of brain homogenates with L-phenylalanine (Phe) could reverse the free radical effects on brain acetylcholinesterase (AChE) activity, since it has been reported that Phe binds hydroxyl radicals ((*)OH). DESIGN AND
METHODS: Two well established systems were used for production of free radicals: (a) FeSO(4) (84 microM) plus ascorbic acid (400 microM), and (b) FeSO(4), ascorbic acid and H(2)O(2) (1 mM) at 37 degrees C in homogenates of adult rat whole brain. Changes in brain AChE activity were studied in the presence of each system separately.
RESULTS: AChE was inhibited (18-28%) by both systems of free radicals. This inhibition was reversed when the brain homogenate was preincubated with Phe 1.8 mM.
CONCLUSIONS: In accordance with our previous reports, Phe could protect against the direct action of (*)OH radicals on brain AChE and in this way it might be useful in the prevention of certain cholinergic neural dysfunctions.