Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

Heart and liver have rhythm

22.04.2002


The heart beats its own drum.
© SPL


Organ clocks orchestrate physiology.

Your body may feel in tune but your organs are doing their own thing. Our hearts and livers follow their own daily routines, say Boston researchers.

The brain carries a central circadian clock whose activity has a 24-hour cycle. Like town clocks set by the Greenwich tones, the body’s organs run secondary timekeepers. These coordinate regular activities such as metabolism, digestion and blood pressure.



The chiming of each organ clock triggers different waves of gene activity, Charles Weitz and his team now show1. In liver and heart, different sets of genes cycle in a 24-hour phase, they found, with peaks and troughs at different times.

"It shows that different tissues have to be cycling for different reasons," says Ueli Schibler of the University of Geneva in Switzerland. This allows organs to reset their activities according to their own priorities. "It makes a lot of sense," Schibler says.

"Feeding time appears to be the strongest synchronizer," he says. Shifting a mouse’s mealtimes from night to day resets the activity cycles of genes in peripheral organs, he has found; the brain’s clock is unaffected. This allows the appropriate organs to gear up for food processing in anticipation of meals, similar to how a night-shift worker might readjust.

Alcohol, for example, is detoxified most efficiently between 5 and 6 in the evening - in time for the first gin and tonic. "A lot of people are beginning to recognize that the timing of taking drugs is critically important," says Michael Menaker, who studies circadian rhythms at the University of Virginia in Charlottesville. Studies such as Weitz’s will fuel this emerging field of ’chronopharmacology’, he predicts.

Clock watching

Weitz, of Harvard Medical School, and his team compared more than 12,000 genes active in liver and heart over two days while mice were exposed to constant light. Between 8 and 10% of genes in each tissue varied their activity following the 24-hour cycle, they found - a measure of the large influence of time on the body.

But few of the genes cycling in the heart were also cycling in the liver. And although heart genes tend to peak synchronously, liver genes peak through morning, noon and night.

Weitz took a crude look at what these genes do. He found that, despite their dissimilarity, they span a similar range of functions in each tissue, including cell communication, metabolism and transport.

The central clock, meanwhile, keeps the other clocks ticking in time. "They’re marching to a drum beaten by the brain," says Weitz, "but peripheral clocks can step out and do their own thing."

How the central clock sends signals to its followers remains unknown - but this study may identify some candidates, says Menaker.

References

  1. Storch, K-F. Extensive and divergenet circadian gene expression in liver and heart. Nature, advanced online publication, doi:10.1038/nature744 (2002).

HELEN PEARSON | © Nature News Service

Weitere Nachrichten aus der Kategorie Medizin Gesundheit:

nachricht Aromatherapie bei COPD
12.05.2015 | Airnergy AG

nachricht Chronische Wunden können heilen
16.10.2017 | Universitätsklinik der Ruhr-Universität Bochum - Herz- und Diabeteszentrum NRW Bad Oeynhausen

Alle Nachrichten aus der Kategorie: Medizin Gesundheit >>>

Die aktuellsten Pressemeldungen zum Suchbegriff Innovation >>>

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

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Topologische Isolatoren: Neuer Phasenübergang entdeckt

Physiker des HZB haben an BESSY II Materialien untersucht, die zu den topologischen Isolatoren gehören. Dabei entdeckten sie einen neuen Phasenübergang zwischen zwei unterschiedlichen topologischen Phasen. Eine dieser Phasen ist ferroelektrisch: das bedeutet, dass sich im Material spontan eine elektrische Polarisation ausbildet, die sich durch ein äußeres elektrisches Feld umschalten lässt. Dieses Ergebnis könnte neue Anwendungen wie das Schalten zwischen unterschiedlichen Leitfähigkeiten ermöglichen.

Topologische Isolatoren zeichnen sich dadurch aus, dass sie an ihren Oberflächen Strom sehr gut leiten, während sie im Innern Isolatoren sind. Zu dieser neuen...

Im Focus: Smarte Sensoren für effiziente Prozesse

Materialfehler im Endprodukt können in vielen Industriebereichen zu frühzeitigem Versagen führen und den sicheren Gebrauch der Erzeugnisse massiv beeinträchtigen. Eine Schlüsselrolle im Rahmen der Qualitätssicherung kommt daher intelligenten, zerstörungsfreien Sensorsystemen zu, die es erlauben, Bauteile schnell und kostengünstig zu prüfen, ohne das Material selbst zu beschädigen oder die Oberfläche zu verändern. Experten des Fraunhofer IZFP in Saarbrücken präsentieren vom 7. bis 10. November 2017 auf der Blechexpo in Stuttgart zwei Exponate, die eine schnelle, zuverlässige und automatisierte Materialcharakterisierung und Fehlerbestimmung ermöglichen (Halle 5, Stand 5306).

Bei Verwendung zeitaufwändiger zerstörender Prüfverfahren zieht die Qualitätsprüfung durch die Beschädigung oder Zerstörung der Produkte enorme Kosten nach...

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics
Veranstaltungen

DFG unterstützt Kongresse und Tagungen - Dezember 2017

17.10.2017 | Veranstaltungen

Intelligente Messmethoden für die Bauwerkssicherheit: Fachtagung „Messen im Bauwesen“ am 14.11.2017

17.10.2017 | Veranstaltungen

Meeresbiologe Mark E. Hay zu Gast bei den "Noblen Gesprächen" am Beutenberg Campus in Jena

16.10.2017 | Veranstaltungen

 
VideoLinks
B2B-VideoLinks
Weitere VideoLinks >>>
Aktuelle Beiträge

Mikroben hinterlassen "Fingerabdrücke" auf Mars-Gestein

17.10.2017 | Biowissenschaften Chemie

Vorhersagen bestätigt: Schwere Elemente bei Neutronensternverschmelzungen nachgewiesen

17.10.2017 | Physik Astronomie

Kaiserschnitt-Risiko ist vererbbar

17.10.2017 | Biowissenschaften Chemie