Effect of mealing on plasma and brain amino acid, and brain monoamine in rats after oral aspartame.
Aspartame (APM; L-aspartyl-L-phenylalanine methyl ester) was investigated for its ability to alter brain amino acids and monoamines in overnight fasted rats allowed to consume commercial diets for 60 minutes. In addition, the effects of mealing on the changes in plasma and brain amino acids and brain monoamines induced by glucose and/or insulin, and known pharmacologically active compounds, were studied. The consumption of the commercial chow largely prevented changes in blood glucose and amino acids, and brain amino acids and the monoamines dopamine, norepinephrine and serotonin that might be expected to occur following glucose with or without insulin. Feeding failed to prevent changes in the above parameters when 5-hydroxy-tryptophan, p-chlorophenylalanine and reserpine were administered. The oral administration of up to 250 mg/kg BW APM with water or glucose followed by free feeding failed to alter brain monoamines. These studies demonstrate the potent ability of food to normalize biochemical parameters in blood and brain that otherwise might occur, and clearly show the lack of effect on brain monoamine levels of abuse doses of APM when administered with food.
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000596:Amino Acids / Q000097:blood / Q000378:metabolism*; D000818:Animals; D001218:Aspartame / Q000494:pharmacology*; D001679:Biogenic Amines / Q000378:metabolism*; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004151:Dipeptides / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism; D010134:Fenclonine / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012110:Reserpine / Q000494:pharmacology; D012701:Serotonin / Q000378:metabolism
D000596:Amino Acids; D001679:Biogenic Amines; D004151:Dipeptides; D007328:Insulin; D012701:Serotonin; D012110:Reserpine; D006916:5-Hydroxytryptophan; D005947:Glucose; D010134:Fenclonine; D004298:Dopamine; D009638:Norepinephrine; D001218:Aspartame