The decrease of serotonin release induced by a tryptophan-free amino acid diet does not affect spatial and passive avoidance learning.
We assessed whether consumption of a diet lacking in tryptophan (TRP) resulted in alteration in learning and memory performance and hippocampal 5-HT release in rats. Two hours after the acute administration of TRP-free (T) and balanced (B) diet rats were trained in a one-trial passive avoidance task. The two groups of rats showed no significant difference in retention latencies. Two other groups of rats, fed with the above diets during the acquisition of a radial-arm maze task, showed no difference in baseline performance. The acute ingestion of the T diet produced a significant and long lasting decrease of hippocampal and cortical 5-HT release in rats when compared to the B diet, while the 12th day of the T diet, 5-HT was not detectable in the dialysate. These data indicate that the diminished brain release of 5-HT induced by a T diet is not sufficient to impair cognitive processes.
Stancampiano
R
R
Institute of Human Physiology, University of Cagliari, Italy.
Cocco
S
S
Melis
F
F
Cugusi
C
C
Sarais
L
L
Fadda
F
F
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D002540:Cerebral Cortex / Q000737:chemistry / Q000378:metabolism; D004032:Diet; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D013037:Spatial Behavior / Q000187:drug effects*; D014364:Tryptophan / Q000494:pharmacology*
D012701:Serotonin; D014364:Tryptophan