Neuroprotective effect of L-lysine monohydrochloride on acute iterative anoxia in rats with quantitative analysis of electrocorticogram.

Lysine is one of the indispensible amino acids and L-lysine monohydrochloride (LMH) is widely available to public as a nonprescription oral supplement. Potential clinical usefulness of oral LMH supplements has been indicated in stroke, hypertension, and seizure induced by pentylenetetrazole (PTZ), etc. We compared the effects of LMH and flunarizine on the Electrocorticogram (EcoG) of rats intragastrically administered 1 hour before anoxia. LMH dose-dependently prolonged the time reaching the lowest ECoG average amplitude after anoxia and decreased the recovery time after recirculation in both 0.63 g/kg and 1.26 g/kg groups. There was significant difference between the LMH- and saline-pretreated groups but no significant difference between the 1.26 g/kg LMH- and 2.5 mg/kg flunarizine-pretreated groups. The difference was not significant in the 2.52 g/kg group. The ECoG average amplitude did not reach isoelectric point and the lowest average amplitude was 10 percent of that of nomoxia in the 1.26 g/kg LMH-pretreated group during 2-min anoxia. The average amplitude pretreated with LMH (0.63 and 1.26 g/kg) was lower than that of those pretreated with saline and flunarizine. The results tend to indicate that LMH can protect brain cells against anoxia by means of providing energy, reducing cerebral metabolic rate and inhibiting the effect of the excitable amino acids.