Navigation Links
Medicine: The heart's metronome
Date:11/12/2013

A specific cell population is responsible for ensuring that our heartbeat remains regular. Researchers from Ludwig-Maximilians-Universitaet (LMU) in Munich have now elucidated the mode of action of one of the crucial components of the heart's intrinsic pacemaker.

The heart possesses a pacemaker of its very own. Specialized pacemaker cells in the so-called sinoatrial node in the left ventricle of the heart control its rate of contraction and relaxation by orchestrating a recurring sequence of electrical signals. Specific proteins known as HCN channels, which are located in the surface membranes of pacemaker cells, play a central role in the generation and transmission of these signals. These proteins function as pores for the passage of electrically charged atoms (ions) across the cell membrane. Because the pore diameter can be regulated, the channels can control the flow of ions across the membrane, and thus determine the difference in electrical potential between the inner and outer surfaces of the cell. Cyclical changes in this parameter give rise to autonomously generated, rhythmic electrical impulses that dictate heartbeat and cardiac rhythmicity.

HCN channels are found primarily in the heart and in the brain, and come in four subtypes, HCN1-4. HCN4 is responsible for about 80% of the total ion current that passes through HCN channels in the sinoatrial node. The other 20% is carried by HCN1 and HCN2. "But while the functions of HCN2 and HCN4 in the sinoatrial node have been extensively studied, the impact of HCN1 on heart rate has so far remained unknown," says Professor Christian Wahl-Schott of the Department of Pharmacy at LMU, who has now closed this gap in our knowledge of the heart's intrinsic pacemaker.

Wahl-Schott and his team and also researchers from Professor Martin Biel's group, tackled the problem by using a mouse strain in which the HCN1 channels in the cells of the sino-atrial node are defective. With the aid of this new experimental model, they were able to demonstrate, for the first time, that HCN1 is involved not in generating the electrical impulse but also in its propagation within the node. Defects in HCN1 function compromise the normal operation of the pacemaker. This results in bradycardia a pathological reduction in heart rate and increases the incidence of arrhythmias. As a consequence, overall cardiac output is significantly reduced. "We were also able to confirm these effects in vivo by means of telemetric electrocardiography," Wahl-Schott adds.

Defects in cells of the sino-atrial node are associated with sudden cardiac arrest, and more than half of all implantations of artificial pacemakers worldwide are carried out on patients who suffer from such conditions. But the new findings regarding the role of HCN1 in the regulation of heart function are actually of clinical interest for two reasons. On the one hand, this channel subtype offers a promising target for drugs designed to normalize heartbeat frequency. However, HCN1 is also found in nerve cells in the brain, where it likewise acts to control rates of neural firing. This explains why HCN1 blockers are under consideration for use in the treatment of epilepsy, chronic pain and depression. "In light of our results, the potential effects of HCN1 blockers on cardiac function should be carefully assessed before such agents are used in other contexts," Wahl-Schott warns.


'/>"/>

Contact: Luise Dirscherl
dirscherl@lmu.de
49-892-180-2706
Ludwig-Maximilians-Universitt Mnchen
Source:Eurekalert

Related medicine news :

1. The Khalili Center for Bariatric Care Seconds the Findings of The New England Journal of Medicine: Surgical Skills Are Essential
2. Study in New England Journal of Medicine: Colonoscopy saves lives
3. Treating Allergies with Traditional Medicine: Ayurvedic Medicine During the Spring Season 2013
4. Ancient Native Remedy: Healing with Clay prescribed as Powerful Medicine: Zion Health's Clay Bath Detox Minerals now Available at Weaver’s Way Co-op in Philadelphia
5. Austin Sports Medicine: Post-Race Recovery Tips from Medicine in Motion
6. Austin Sports Medicine: Race Day Tips from Medicine in Motion
7. Regenerative medicine: Clinical trials launched for the treatment of delayed union fractures
8. Personalizing medicine: New American Chemical Society Prized Science video
9. Molecular Genetics & Genomic Medicine: New open access journal launched by Wiley
10. Applied nanobiomedicine: Exploiting nanoparticles to hunt for hidden cancer cells
11. Clotting protein hardens aging hearts
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/21/2017)... ... April 21, 2017 , ... Young Asset Protection, an insurance ... throughout the greater Pittsburgh metropolitan region, is joining forces with the local chapter ... differently-abled children. , Variety the Children’s Charity is a national organization dedicated to ...
(Date:4/21/2017)... ... April 21, 2017 , ... The Hong Kong Polytechnic University (PolyU) launched ... among higher education institutions in Hong Kong to support teaching, learning and research. It ... and quantity of facilities in Hong Kong. , With an area of 620 ...
(Date:4/21/2017)... , ... April 21, 2017 , ... ... held the much anticipated Regional Primary Care Spring Symposium on April 1, 2017 ... local medical community, offering physicians and healthcare providers an opportunity to learn about ...
(Date:4/21/2017)... , ... April 21, 2017 , ... Westside Dental ... personalized dental care since 1985. After thirty-two years, Dr. Latner has become one of ... help my numerous clients over the years with all their dental needs,” said Dr. ...
(Date:4/21/2017)... ... April 21, 2017 , ... ... reveals good news for older shoulder replacement patients; post-operative recovery just might be ... two groups of patients presenting with osteoarthritis following surgery: 262 patients under 65 ...
Breaking Medicine News(10 mins):
(Date:4/20/2017)... DUBLIN , April 20, 2017 ... the "Global Biosimilar Pipeline and Market Prospects: Addressing ... report to their offering. ... "Global Biosimilar Pipeline and Market ... by Design" provides an in-depth assessment of the current ...
(Date:4/20/2017)... 20, 2017  AbbVie (NYSE: ABBV), a global ... of chronic hepatitis C virus (HCV) infected patients ... and compensated cirrhosis (Child-Pugh A) achieved sustained virologic ... with its investigational, pan-genotypic regimen of glecaprevir/pibrentasvir (G/P). ... following 12 weeks of G/P treatment without ribavirin. ...
(Date:4/19/2017)... Medical Corporation (TSX: CRH) (NYSE MKT: CRHM) (the "Company"), announces that it ... 2017 at the Sheraton Hotel in Toronto, Ontario ... the Company is scheduled to present on Tuesday, May 2 at ... Chairman of the Board, Tony Holler will also attend ... For more details ...
Breaking Medicine Technology: