TY - JOUR
T1 - The effects of paradoxical sleep deprivation and valine on spatial learning and brain 5-HT metabolism
AU - Youngblood, Bradley D.
AU - Smagin, Gennady N.
AU - Elkins, Phillip D.
AU - Ryan, Donna H.
AU - Harris, Ruth B.S.
N1 - Funding Information:
This work was supported by the U.S. Army Medical Research and Development Command Grant DAMD 17-97-2-7013. The authors thank Stephen M. Redmann, Jr. for statistical analysis of the data.
PY - 1999/11
Y1 - 1999/11
N2 - We have previously reported that rapid eye movement sleep deprivation (REMSD), induced by the flower pot technique, causes a deficit in reference spatial memory and increases rates of serotonin (5-HT) metabolism in the brain. In this study we used increased concentrations of dietary valine to inhibit tryptophan (TRP) transport across the blood-brain barrier in an attempt to modify the REMSD-induced increase of 5-HT metabolism. Rats were fed either a control diet or the same diet supplemented to 2% by weight valine, and were allocated to one of three experimental groups: cage control (CC), stress tank control (TC), or REMSD. Reference and working spatial memory of all rats was tested in a Morris water maze on Days 2, 3, and 4. REMSD produced a significant decrement in reference memory on Days 2 and 4, independent of dietary condition. The valine diet had a detrimental effect on the reference memory of TC rats on Day 2 but not Day 4. Measurements made on Day 4 indicated that the valine diet decreased brain TRP only in the CC rats. In contrast, the valine diet did not prevent increases in brain TRP or 5-HT metabolism in REMSD rats, and increased hypothalamic and brain stem TRP concentrations and the hippocampal 5-HIAA/5-HT ratio in TC rats. These results indicate that dietary valine does not prevent REMSD-induced changes in spatial memory or serotonin metabolism, although it does reduce brain TRP in nonstressed rats.
AB - We have previously reported that rapid eye movement sleep deprivation (REMSD), induced by the flower pot technique, causes a deficit in reference spatial memory and increases rates of serotonin (5-HT) metabolism in the brain. In this study we used increased concentrations of dietary valine to inhibit tryptophan (TRP) transport across the blood-brain barrier in an attempt to modify the REMSD-induced increase of 5-HT metabolism. Rats were fed either a control diet or the same diet supplemented to 2% by weight valine, and were allocated to one of three experimental groups: cage control (CC), stress tank control (TC), or REMSD. Reference and working spatial memory of all rats was tested in a Morris water maze on Days 2, 3, and 4. REMSD produced a significant decrement in reference memory on Days 2 and 4, independent of dietary condition. The valine diet had a detrimental effect on the reference memory of TC rats on Day 2 but not Day 4. Measurements made on Day 4 indicated that the valine diet decreased brain TRP only in the CC rats. In contrast, the valine diet did not prevent increases in brain TRP or 5-HT metabolism in REMSD rats, and increased hypothalamic and brain stem TRP concentrations and the hippocampal 5-HIAA/5-HT ratio in TC rats. These results indicate that dietary valine does not prevent REMSD-induced changes in spatial memory or serotonin metabolism, although it does reduce brain TRP in nonstressed rats.
KW - Reference memory
KW - Serotonin metabolism
KW - Sleep deprivation
KW - Stress
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U2 - 10.1016/S0031-9384(99)00120-1
DO - 10.1016/S0031-9384(99)00120-1
M3 - Article
C2 - 10604833
AN - SCOPUS:0032714198
SN - 0031-9384
VL - 67
SP - 643
EP - 649
JO - Physiology and Behavior
JF - Physiology and Behavior
IS - 5
ER -