Format

Send to

Choose Destination
Sleep. 2012 Jun 1;35(6):861-9. doi: 10.5665/sleep.1890.

Decoupling of sleepiness from sleep time and intensity during chronic sleep restriction: evidence for a role of the adenosine system.

Author information

1
VA Boston Healthcare System, Research Service and Harvard Medical School, Department of Psychiatry, Brockton, MA 02301-5596, USA. youngsoo_kim@hms.harvard.edu

Abstract

STUDY OBJECTIVE:

Sleep responses to chronic sleep restriction (CSR) might be very different from those observed after short-term total sleep deprivation. For example, after sleep restriction continues for several consecutive days, animals no longer express compensatory increases in daily sleep time and sleep intensity. However, it is unknown if these allostatic, or adaptive, sleep responses to CSR are paralleled by behavioral and neurochemical measures of sleepiness.

DESIGN:

This study was designed to investigate CSR-induced changes in (1) sleep time and intensity as a measure of electrophysiological sleepiness, (2) sleep latency as a measure of behavioral sleepiness, and (3) brain adenosine A1 (A1R) and A2a receptor (A2aR) mRNA levels as a putative neurochemical correlate of sleepiness.

SUBJECTS:

Male Sprague-Dawley rats

INTERVENTIONS:

A 5-day sleep restriction (SR) protocol consisting of 18-h sleep deprivation and 6-h sleep opportunity each day.

MEASUREMENT AND RESULTS:

Unlike the first SR day, rats did not sleep longer or deeper on days 2 through 5, even though they exhibited significant elevations of behavioral sleepiness throughout all 5 SR days. For all SR days and recovery day 1, A1R mRNA in the basal forebrain was maintained at elevated levels, whereas A2aR mRNA in the frontal cortex was maintained at reduced levels.

CONCLUSION:

CSR LEADS TO A DECOUPLING OF SLEEPINESS FROM SLEEP TIME AND SLEEP INTENSITY, SUGGESTING THAT THERE ARE AT LEAST TWO DIFFERENT SLEEP REGULATORY SYSTEMS: one mediating sleepiness (homeostatic) and the other mediating sleep time/intensity (allostatic). The time course of changes observed in adenosine receptor mRNA levels suggests that the basal forebrain and cortical adenosine system might mediate sleepiness rather than sleep time or intensity.

KEYWORDS:

Chronic sleep restriction; adenosine; allostasis; rat; receptor; sleep latency

PMID:
22654205
PMCID:
PMC3353031
DOI:
10.5665/sleep.1890
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center