The time course of adenosine, nitric oxide (NO) and inducible NO synthase changes in the brain with sleep loss and their role in the non-rapid eye movement sleep homeostatic cascade.
Both adenosine and nitric oxide (NO) are known for their role in sleep homeostasis, with the basal forebrain (BF) wakefulness center as an important site of action. Previously, we reported a cascade of homeostatic events, wherein sleep deprivation (SD) induces the production of inducible nitric oxide synthase (iNOS)-dependent NO in BF, leading to enhanced release of extracellular adenosine. In turn, increased BF adenosine leads to enhanced sleep intensity, as measured by increased non-rapid eye movement sleep EEG delta activity. However, the presence and time course of similar events in cortex has not been studied, although a frontal cortical role for the increase in non-rapid eye movement recovery sleep EEG delta power is known. Accordingly, we performed simultaneous hourly microdialysis sample collection from BF and frontal cortex (FC) during 11 h SD. We observed that both areas showed sequential increases in iNOS and NO, followed by increases in adenosine. BF increases began at 1 h SD, whereas FC increases began at 5 h SD. iNOS and Fos-double labeling indicated that iNOS induction occurred in BF and FC wake-active neurons. These data support the role of BF adenosine and NO in sleep homeostasis and indicate the temporal and spatial sequence of sleep homeostatic cascade for NO and adenosine.
Laboratory of Neuroscience, Department of Psychiatry, VA Boston Healthcare System and Harvard Medical School, West Roxbury, Massachusetts, USA. anna_kalinchuk@hms.harvard.edu
Anna V
AV
Kalinchuk
Robert W
RW
McCarley
Tarja
T
Porkka-Heiskanen
Radhika
R
Basheer
D000241:Adenosine / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism* / Q000502:physiology; D004569:Electroencephalography / Q000379:methods; D006706:Homeostasis / Q000502:physiology*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism* / Q000502:physiology; D016548:Prosencephalon / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012892:Sleep Deprivation / Q000378:metabolism*; D012894:Sleep Stages / Q000502:physiology*; D013997:Time Factors
D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D000241:Adenosine