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 Tropenviren bald auch in Europa? Bayreuther Forscher untersuchen Folgen des Klimawandels
21.06.2017 | Universität Bayreuth

nachricht Sonnencremes: Darauf kommt es bei der Darstellung der Wirksamkeit an
21.06.2017 | Max-Planck-Institut für Bildungsforschung

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: Klima-Satellit: Mit robuster Lasertechnik Methan auf der Spur

Hitzewellen in der Arktis, längere Vegetationsperioden in Europa, schwere Überschwemmungen in Westafrika – mit Hilfe des deutsch-französischen Satelliten MERLIN wollen Wissenschaftler ab 2021 die Emissionen des Treibhausgases Methan auf der Erde erforschen. Möglich macht das ein neues robustes Lasersystem des Fraunhofer-Instituts für Lasertechnologie ILT in Aachen, das eine bisher unerreichte Messgenauigkeit erzielt.

Methan entsteht unter anderem bei Fäulnisprozessen. Es ist 25-mal wirksamer als das klimaschädliche Kohlendioxid, kommt in der Erdatmosphäre aber lange nicht...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: Die Schweiz in Pole-Position in der neuen ESA-Mission

Die Europäische Weltraumagentur ESA gab heute grünes Licht für die industrielle Produktion von PLATO, der grössten europäischen wissenschaftlichen Mission zu Exoplaneten. Partner dieser Mission sind die Universitäten Bern und Genf.

Die Europäische Weltraumagentur ESA lanciert heute PLATO (PLAnetary Transits and Oscillation of stars), die grösste europäische wissenschaftliche Mission zur...

Im Focus: Forscher entschlüsseln erstmals intaktes Virus atomgenau mit Röntgenlaser

Bahnbrechende Untersuchungsmethode beschleunigt Proteinanalyse um ein Vielfaches

Ein internationales Forscherteam hat erstmals mit einem Röntgenlaser die atomgenaue Struktur eines intakten Viruspartikels entschlüsselt. Die verwendete...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

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

„Fit für die Industrie 4.0“ – Tagung von Hochschule Darmstadt und Schader-Stiftung am 27. Juni

22.06.2017 | Veranstaltungen

Forschung zu Stressbewältigung wird diskutiert

21.06.2017 | Veranstaltungen

Die Zukunft der Informationstechnologie - Internationale Konferenz erstmals in Aachen

21.06.2017 | Veranstaltungen

 
VideoLinks
B2B-VideoLinks
Weitere VideoLinks >>>
Aktuelle Beiträge

Auf die richtige Verbindung kommt es an: Tiefe Hirnstimulation bei Parkinsonpatienten individuell anpassen

22.06.2017 | Medizintechnik

CO2-neutraler Wasserstoff aus Biomasse

22.06.2017 | Biowissenschaften Chemie

Klima-Satellit: Mit robuster Lasertechnik Methan auf der Spur

22.06.2017 | Geowissenschaften