Chronic aspartame affects T-maze performance, brain cholinergic receptors and Na+,K+-ATPase in rats.
This study demonstrated that chronic aspartame consumption in rats can lead to altered T-maze performance and increased muscarinic cholinergic receptor densities in certain brain regions. Control and treated rats were trained in a T-maze to a particular side and then periodically tested to see how well they retained the learned response. Rats that had received aspartame (250 mg/kg/day) in the drinking water for 3 or 4 months showed a significant increase in time to reach the reward in the T-maze, suggesting a possible effect on memory due to the artificial sweetener. Using [(3)H]quinuclidinyl benzilate (QNB) (1 nM) to label muscarinic cholinergic receptors and atropine (10(-6) M) to determine nonspecific binding in whole-brain preparations, aspartame-treated rats showed a 31% increase in receptor numbers when compared to controls. In aspartame-treated rats, there was a significant increase in muscarinic receptor densities in the frontal cortex, midcortex, posterior cortex, hippocampus, hypothalamus and cerebellum of 80%, 60%, 61%, 65%, 66% and 60%, respectively. The midbrain was the only area where preparations from aspartame-treated rats showed a significant increase in Na(+),K(+)-ATPase activity. It can be concluded from these data that long-term consumption of aspartame can affect T-maze performance in rats and alter receptor densities or enzymes in brain.
Christian
Brandon
B
Department of Pharmacology, Brody School of Medicine, East Carolina University, Greenville, NC 27858, USA.
McConnaughey
Kenneth
K
Bethea
Elena
E
Brantley
Scott
S
Coffey
Amy
A
Hammond
Leigha
L
Harrell
Shelly
S
Metcalf
Kasee
K
Muehlenbein
Danielle
D
Spruill
Willie
W
Brinson
Leslie
L
McConnaughey
Mona
M
D000818:Animals; D001218:Aspartame / Q000008:administration & dosage*; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D018782:Maze Learning / Q000187:drug effects* / Q000502:physiology; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D011597:Psychomotor Performance / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011950:Receptors, Cholinergic / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D011950:Receptors, Cholinergic; D000254:Sodium-Potassium-Exchanging ATPase; D001218:Aspartame