title: The role of adenosine in the maturation of sleep homeostasis in rats.
abstract: Sleep homeostasis in rats undergoes significant maturational changes during postweaning development, but the underlying mechanisms of this process are unknown. In the present study we tested the hypothesis that the maturation of sleep is related to the functional emergence of adenosine (AD) signaling in the brain. We assessed postweaning changes in 1) wake-related elevation of extracellular AD in the basal forebrain (BF) and adjacent lateral preoptic area (LPO), and 2) the responsiveness of median preoptic nucleus (MnPO) sleep-active cells to increasing homeostatic sleep drive. We tested the ability of exogenous AD to augment homeostatic responses to sleep deprivation (SD) in newly weaned rats. In groups of postnatal day (P)22 and P30 rats, we collected dialysate from the BF/LPO during baseline (BSL) wake-sleep, SD, and recovery sleep (RS). HPLC analysis of microdialysis samples revealed that SD in P30 rats results in significant increases in AD levels compared with BSL. P22 rats do not exhibit changes in AD levels in response to SD. We recorded neuronal activity in the MnPO during BSL, SD, and RS at P22/P30. MnPO neurons exhibited adult-like increases in waking neuronal discharge across SD on both P22 and P30, but discharge rates during enforced wake were higher on P30 vs. P22. Central administration of AD (1 nmol) during SD on P22 resulted in increased sleep time and EEG slow-wave activity during RS compared with saline control. Collectively, these findings support the hypothesis that functional reorganization of an adenosinergic mechanism of sleep regulation contributes to the maturation of sleep homeostasis.
  
  
  
  Brain mechanisms that regulate the maturation of sleep are understudied. The present study generated first evidence about a potential mechanistic role for adenosine in the maturation of sleep homeostasis. Specifically, we demonstrate that early postweaning development in rats, when homeostatic response to sleep loss become adult like, is characterized by maturational changes in wake-related production/release of adenosine in the brain. Pharmacologically increased adenosine signaling in developing brain facilitates homeostatic responses to sleep deprivation.
authors: Research Service (151A3), Veterans Affairs Greater Los Angeles Healthcare System, North Hills, California; igvilia@ucla.edu.|Department of Medicine, University of California, Los Angeles, California.|Ilia State University, Tbilisi, Georgia; and.
authors: Irma
authors: 0000-0003-2504-9698
authors: I
authors: Gvilia
authors: Research Service (151A3), Veterans Affairs Greater Los Angeles Healthcare System, North Hills, California.|Department of Medicine, University of California, Los Angeles, California.
authors: Natalia
authors: N
authors: Suntsova
authors: Research Service (151A3), Veterans Affairs Greater Los Angeles Healthcare System, North Hills, California.
authors: Andrey
authors: A
authors: Kostin
authors: Department of Psychiatry, Harvard Medical School, Boston, Massachusetts.
authors: Anna
authors: A
authors: Kalinchuk
authors: Research Service (151A3), Veterans Affairs Greater Los Angeles Healthcare System, North Hills, California.|Department of Psychology, University of California, Los Angeles, California.
authors: Dennis
authors: D
authors: McGinty
authors: Department of Psychiatry, Harvard Medical School, Boston, Massachusetts.
authors: Radhika
authors: R
authors: Basheer
authors: Research Service (151A3), Veterans Affairs Greater Los Angeles Healthcare System, North Hills, California.|Department of Medicine, University of California, Los Angeles, California.
authors: Ronald
authors: R
authors: Szymusiak
mesh_terms: D000241:Adenosine / Q000378:metabolism* / Q000494:pharmacology; D000367:Age Factors; D000375:Aging / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002851:Chromatography, High Pressure Liquid; D004569:Electroencephalography; D004576:Electromyography; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology*; D011301:Preoptic Area / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D016548:Prosencephalon / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012890:Sleep / Q000187:drug effects / Q000502:physiology*; D012892:Sleep Deprivation / Q000503:physiopathology; D014851:Wakefulness
chemical_list: D000241:Adenosine
keywords: adenosine; postweaning development; preoptic hypothalamus; rats; sleep homeostasis