How much calcium could a hibernating woodchuck's heart cells sequester, if a hibernating woodchuck's heart cells could sequester calcium? More than enough, it turns out, to protect the animals from cardiac arrhythmias – abnormal heart rhythms such as ventricular tachycardia and ventricular fibrillation that can lead to sudden cardiac death – according to a new study of the hibernating animals that may provide insight into arrhythmia therapies. The findings will be presented at a poster session at the 56th Annual Meeting of the Biophysical Society (BPS), which will take place Feb. 25-29 in San Diego, Calif.
Bear and bats can be roused from their slumber by external stimuli. But woodchucks (Marmota monax), also known as groundhogs, are "true hibernators," which means they can enter a profoundly altered physiological state: their body temperature drops to near-ambient levels (often as low as freezing) and heart and respiration rates slow dramatically. Despite – or perhaps because of – these changes, hibernating animals have been found to be more resistant to cardiac arrhythmias and sudden cardiac death.
Electrophysiologist Lai-Hua Xie, an assistant professor at the University of Medicine and Dentistry of New Jersey (UMDNJ)-New Jersey Medical School in Newark, and his colleagues examined muscle cells, or myocytes, isolated in winter and in summer from woodchucks. Using a charge-coupled device (CCD) camera, the researchers monitored the release and uptake of calcium ions when the cells were activated. The team found that in winter woodchucks, the myocyte sarcoplasmic reticulum – the membrane system in muscle cells that stores and releases calcium – had less spontaneous leakage of calcium, released more of it during excitation, and took it back up faster than that of summer woodchucks or non-hibernating animals. This is likely, he says, "to generate a stronger contraction and faster relaxation, and most importantly, to prevent abnormal changes in the heart's electrical activities called afterdepolarizations."
The overall effect, Xie says, is a "higher resistance to arrhythmia in woodchucks in winter. Understanding these cardiac adaptive mechanisms in hibernators may suggest new strategies to protect non-hibernating animals, especially humans, from fatal cardiac arrhythmias induced by hypothermic stresses and myocardial ischemia."
Xie and his colleagues conducted the work with funding from the National Institutes of Health and in collaboration with Stephen Vatner, director of the UMDNJ-New Jersey Medical School Cardiovascular Research Center.
The presentation, "Calcium handling properties in a hibernating animal: Insights into antiarrhythmic mechanisms," is at 1:45 on Sunday, Feb. 26, 2012, in the San Diego Convention Center, Hall FGH. ABSTRACT: http://tinyurl.com/7mtrp4a
This news release was prepared for the Biophysical Society (BPS) by the American Institute of Physics (AIP).ABOUT THE 2012 ANNUAL MEETING
The 56th Annual Meeting will be held at the San Diego Convention Center (111 W. Harbor Drive, San Diego, CA 92101), located three miles from the San Diego International Airport and less than one mile from the Amtrak station. The San Diego Trolley has two stops directly in front of the Center at Harbor Drive/First Avenue and Harbor Drive/Fifth Avenue.QUICK LINKS
Housing and Travel Information: http://www.biophysics.org/2012meeting/AccommodationsTravel/HotelInformation/tabid/2479/Default.aspx
Program Abstracts and Itinerary Planner: http://www.abstractsonline.com/plan/start.aspx?mkey=%7B5B4BAD87%2D5B6D%2D4994%2D84CE%2DB3B13E2AEAA3%7DPRESS REGISTRATION
Ellen R. Weiss | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy