title: Protective effect of L-phenylalanine on rat brain acetylcholinesterase inhibition induced by free radicals.
abstract: 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).
  
  
  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.
authors.affiliation: Department of Experimental Physiology, University of Athens, Medical School, P.O. Box 65257, GR-154 01, Athens, Greece. stsakir@cc.uoa.gr
authors.forename: S
authors.initials: S
authors.lastname: Tsakiris
authors.forename: P
authors.initials: P
authors.lastname: Angelogianni
authors.forename: K H
authors.initials: KH
authors.lastname: Schulpis
authors.forename: J C
authors.initials: JC
authors.lastname: Stavridis
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000375:Aging; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D001921:Brain / Q000201:enzymology* / Q000254:growth & development; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D005260:Female; D005290:Ferric Compounds / Q000494:pharmacology*; D005296:Ferrous Compounds / Q000494:pharmacology; D005609:Free Radicals / Q000494:pharmacology; D005625:Frontal Lobe / Q000201:enzymology; D006624:Hippocampus / Q000201:enzymology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007031:Hypothalamus / Q000201:enzymology; D007700:Kinetics; D008297:Male; D010649:Phenylalanine / Q000494:pharmacology*; D010902:Pituitary Gland / Q000201:enzymology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002800:Cholinesterase Inhibitors; D005290:Ferric Compounds; D005296:Ferrous Compounds; D005609:Free Radicals; C020748:ferrous sulfate; D010649:Phenylalanine; C061126:iron(III)-ascorbic acid complex; D006861:Hydrogen Peroxide; D000110:Acetylcholinesterase; D001205:Ascorbic Acid