Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New research explores ’early bird’ and ’night owl’ sleep patterns

19.04.2004


An animal study finds a link in genetics that determines our sleep patterns



Are you annoyed by cheerful "morning people?" Do you ever wonder how "night owls" can keep going? Most of us ask these questions because we are in between these two extremes, and take a while to get going early in the morning and tire long before midnight. This entire spectrum reflects the broad, normal variation in sleep patterns in humans that is rooted in the very genetic foundations of how our body works. Because these variations occur within our population and differ with age, the presumption exists that the differences in sleep patterns are controlled by complex mechanisms with contributions from multiple genes and influenced by environmental factors.

Linking our genetic make-up and sleep related disorders require data that compare genetic differences that might explain the basis of sleep disorders. Knowing what causes these disorders is important -- getting a good night sleep is now a challenge for some 50 to 70 millions American of all ages. A 2002 National Sleep Foundation annual survey reported that nearly 40 percent of adults 30 to 64 years old, and 44 percent of those age 18 to 29, reported that daytime sleepiness is so severe that it interferes with work and social functioning at least a few days each month. Excessive daytime sleepiness has been blamed on interference in cognitive functioning, motor vehicle crashes (especially at night), poor job performance and reduced productivity. While researchers have learned much about the basic mechanism underlying the control of sleep and its importance on our daily function and health, they have only just begun to examine the complex genetic and environmental interactions that shape sleep and health.


A New Study

An important step in this research is a new study that involved three different strains of inbred laboratory rats and measurements of their movement and continuous sleep in controlled environmental chambers for three days and nights. The study examined 24-hour variations in the animals’ slow wave sleep, activity and changes from rest to activity. The comparisons between the three strains have led the researchers to conclude that there were significant variations in these measures, strongly suggesting that the findings were due to genetic differences.

The authors of "Circadian Slow Wave Sleep and Movement Behavior are under Genetic Control in Inbred Strains of Rat," are Thom R. Feroah, Todd Sleeper, Dan Brozoski, Joan Forder, Tom B. Rice, and Hubert V. Forster from the Medical College of Wisconsin, Milwaukee, WI. Dr. Feroah will present his team’s findings at the American Physiological Society’s (APS) (www.the-aps.org) annual scientific conference, Experimental Biology 2004, being held April 17-21, 2004, at the Washington, D.C. Convention Center.

Methodology

Research in inbred strains of mice has previously shown distinct variations in the pattern of slow wave sleep between some strains. This study investigated differences in circadian slow wave sleep and activity patterns in three inbred strains of rats previously used in sequencing the rat genome. If a difference in the pattern of slow wave sleep and activity was found, then a dissection of the multigenic basis of the neurophysiological mechanisms involved in the control of slow wave sleep and behavior could then be explored using consomic (chromosomal substitution) rat panels.

In Brown Norway (BN/mcw), Dahl Salt Sensitive (SS), and Fawn Hooded (FH) inbred rats, movement and slow wave sleep were measured continuously for three days in an environmental controlled chambers in which temperature and humidity were held within a limited operating range. Slow wave sleep was determined from electroencephalograph electrodes attached to the skull and electromyograph electrodes in the neck muscles of the rat. The percent of slow wave sleep (percent of SWS; SWS bout length relative to rest time interval), percent of rest (total rest time relative to interval time) and fragmentation of rest (Frag; calculated as the number of transitions (per hour) from a minimum six second rest period to a minimum four second period of activity) was obtained from a computerized open-field activity monitoring system that was integrated with the sleep system.

Results

Unique and significant differences were found within and between strains over the study period. The researchers found that the percentage of slow wave sleep, rest and transitions between rest and activity varied uniquely between strains. This suggests that these findings are due to genetic differences. Furthermore, the inverse relationship between the percentages of slow wave sleep and rest within strains supports the homeostatic control theory of slow wave sleep, which is to restore glycogen during non-REM sleep.

Conclusions

The next step in this research is to examine the consomic rat panels cross of FH and BN that could aid in locating the chromosome region(s) that are at the very basis of the relationship between the slow wave sleep and activity. Similarly, examining the consomic rat panel cross between the SS and FH inbred strains for the chromosomal region(s) that influence the phase shift in the circadian pattern of slow wave sleep and activity could also help understand the complex basis of the early bird and night owl pattern of sleep that is observed in our society.

This research would be important in establishing the genomic basis of normal and abnormal variation in sleep patterns. Further research into the genetic basis of these differences may very well help dissect the multigenic and physiologic mechanistic pathways involved in circadian sleep and behavior in rats that would be homologous to those in humans.


The American Physiological Society (APS) was founded in 1887 to foster basic and applied science, much of it relating to human health. The Bethesda, MD-based Society has more than 11,000 members and publishes 3,800 articles in its 14 peer-reviewed journals every year.

Editor’s Note: For further information or to schedule an interview with Dr. Feroah, please contact Donna Krupa at 703-967-2751 (cell), 703-527-7357 (office) or at djkrupa1@aol.com. Or contact the APS newsroom at 202-249-4009 between 9:00 AM and 6:00 PM EDT April 17-21, 2004.

Donna Krupa | EurekAlert!
Further information:
http://www.the-aps.org/

More articles from Social Sciences:

nachricht Geographers provide new insight into commuter megaregions of the US
01.12.2016 | Dartmouth College

nachricht Sustainable Development Goals lead to lower population growth
30.11.2016 | International Institute for Applied Systems Analysis (IIASA)

All articles from Social Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

IHP presents the fastest silicon-based transistor in the world

05.12.2016 | Power and Electrical Engineering

InLight study: insights into chemical processes using light

05.12.2016 | Materials Sciences

High-precision magnetic field sensing

05.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>