The effects of paradoxical sleep deprivation and valine on spatial learning and brain 5-HT metabolism

Bradley D. Youngblood, Gennady N. Smagin, Phillip D. Elkins, Donna H. Ryan, Ruth B.S. Harris

Research output: Contribution to journalArticle

48 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)643-649
Number of pages7
JournalPhysiology and Behavior
Volume67
Issue number5
DOIs
StatePublished - Nov 1999
Externally publishedYes

Keywords

  • Reference memory
  • Serotonin metabolism
  • Sleep deprivation
  • Stress

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Behavioral Neuroscience

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