title: L-cysteine supplementation prevents exercise-induced alterations in human erythrocyte membrane acetylcholinesterase and Na+,K+-ATPase activities.
abstract: BACKGROUND
  L-Cysteine (L-Cys) is implicated in the reduction of free radical production. The aim of this study was to investigate whether L-Cys supplementation prevents modulation of the activities of erythrocyte membrane acetylcholinesterase (AChE), Na(+),K(+)-ATPase and Mg(2+)-ATPase induced by free radicals in basketball players during training.
  
  
  METHODS
  Blood was obtained from 10 basketball male players before (group A) and after a game (group B) and after 1 week of L-Cys (0.5 g/24 h orally) supplementation before (group C) and after training (group D). Lactate, pyruvate and total antioxidant status (TAS) were measured using commercial kits and the enzyme activities were determined spectrophotometrically.
  
  
  RESULTS
  Both lactate and pyruvate levels remarkably increased after exercise. In contrast, TAS levels significantly decreased in group B, increased in group C and then declined (group D), reaching those of group A. AChE activity was statistically increased post-exercise (3.98+/-0.04 Delta OD/min x mg protein) compared with pre-training (2.90+/-0.05 Delta OD/min x mg protein, p<0.01). Na(+),K(+)-ATPase activity was also higher post-exercise (1.27+/-0.05 micromol Pi/h x mg protein) than that pre-exercise (0.58+/-0.04 micromol Pi/h x mg protein, p<0.001). When the players were supplemented with L-Cys, both AChE and Na(+),K(+)-ATPase activities remained unaltered post-exercise. Mg(2+)-ATPase activities were unchanged in all groups studied.
  
  
  CONCLUSIONS
  L-Cys supplementation may protect the enzyme activities studied against stimulation induced by free radical production during training in athletes by ameliorating their total antioxidant capacity.
authors.affiliation: Department of Experimental Physiology, Medical School, University of Athens, Athens, Greece.
authors.forename: Theodore
authors.initials: T
authors.lastname: Parthimos
authors.forename: Christi
authors.initials: C
authors.lastname: Tsopanakis
authors.forename: Panagoula
authors.initials: P
authors.lastname: Angelogianni
authors.forename: Kleopatra H
authors.initials: KH
authors.lastname: Schulpis
authors.forename: Nickolaos
authors.initials: N
authors.lastname: Parthimos
authors.forename: Stylianos
authors.initials: S
authors.lastname: Tsakiris
mesh_terms: D000110:Acetylcholinesterase / Q000097:blood*; D000328:Adult; D000975:Antioxidants / Q000494:pharmacology; D017301:Ca(2+) Mg(2+)-ATPase / Q000097:blood; D003545:Cysteine / Q000008:administration & dosage*; D019587:Dietary Supplements; D004910:Erythrocyte Membrane / Q000201:enzymology*; D015444:Exercise; D005609:Free Radicals / Q000378:metabolism; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood*
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D000110:Acetylcholinesterase; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase; D003545:Cysteine