Preoptic area neurons and the homeostatic regulation of rapid eye movement sleep.
The median preoptic nucleus (MnPN) and the ventral lateral preoptic area (vlPOA) of the hypothalamus express sleep-related Fos immunoreactivity, and a subset of Fos-immunoreactive neurons (IRNs) in these nuclei contain glutamic acid decarboxylase (GAD), a marker of GABAergic cells. We recently showed that the numbers of Fos-positive (Fos+) and Fos+ GAD-IRNs in both the MnPN and the vlPOA are positively correlated with the total amount of preceding sleep. The present study was designed to clarify whether or not activation of sleep-related neurons in the rat MnPN and vlPOA is associated with rapid eye movement (REM) sleep regulation. Expression of c-fos in MnPN and vlPOA neurons was examined under conditions of spontaneous sleep, REM sleep restriction, and REM sleep recovery after REM sleep restriction. Across all conditions, the number of Fos-IRNs was highest in REM-sleep-restricted rats displaying the highest levels of REM sleep homeostatic pressure/drive, i.e., those rats exhibiting the most frequent attempts to enter REM sleep. This finding provides the first evidence that activation of subsets of MnPN and vlPOA neurons is more strongly related to REM sleep pressure than to REM sleep amount.
Research Service, Veterans Affairs Greater Los Angeles Healthcare System, North Hills, California 91343, USA. irmagvilia@hotmail.com
Irma
I
Gvilia
Amanda
A
Turner
Dennis
D
McGinty
Ronald
R
Szymusiak
D000818:Animals; D015415:Biomarkers; D004569:Electroencephalography; D016762:Genes, fos; D005968:Glutamate Decarboxylase / Q000032:analysis; D006706:Homeostasis / Q000502:physiology*; D007527:Isoenzymes / Q000032:analysis; D008297:Male; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000096:biosynthesis; D009474:Neurons / Q000737:chemistry / Q000502:physiology*; D011301:Preoptic Area / Q000166:cytology / Q000502:physiology*; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012892:Sleep Deprivation / Q000503:physiopathology; D012895:Sleep, REM / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology
D015415:Biomarkers; D007527:Isoenzymes; D009419:Nerve Tissue Proteins; D016760:Proto-Oncogene Proteins c-fos; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1