Featured Research

from universities, journals, and other organizations

Abnormal Heartbeats Caused By Changes In Ion Channel Density

Date:
August 28, 2009
Source:
Journal of Clinical Investigation
Summary:
Two independent studies have determined how changes in the density of different ion channels in the surface membrane of heart muscle cells can lead to life-threatening abnormal heartbeats.

Two independent studies have determined how changes in the density of different ion channels in the surface membrane of heart muscle cells can lead to life-threatening abnormal heartbeats, according to research to be published in the August 24 issue of the Journal of Clinical Investigation.

As Gail Robertson, at the University of Wisconsin — Madison, discusses in an accompanying commentary, these important studies provide new insight into the complex array of mechanisms controlling our heartbeat and how they can be perturbed.

The coordinated contraction of heart muscle cells that ensures a normal heartbeat is controlled by an electrical current that passes from one heart muscle cell to the next and along a special conduction system within the heart. A block in conduction of this electrical current disrupts the heartbeat and is the most common cause of pacemaker implantation. Many diseases that cause conduction block, including progressive familial heart block type I (PFHBI), are inherited. Olaf Pangs and colleagues, at Universitδt Hamburg, Germany, have now linked a mutation in the gene TRPM4 with PFHBI in 3 branches of a large South African Afrikaner pedigree with the disease. The TRPM4 gene is responsible for generating an ion channel that the authors found to be expressed at highest levels in a crucial region of the special conduction system within the human heart. Importantly, the PFHBI-associated mutation increased levels of the TRPM4 channel at the cell surface and blunted conduction of the electrical current.

A noninherited cause of an abnormal heartbeat is low levels of potassium (K+) in the blood, which can trigger life-threatening changes to the heartbeat. Shetuan Zhang and colleagues, at Queen's University, Ontario, have now determined in rabbits that low levels of potassium in the blood cause decreased levels of the IKr ion channel at the surface of rabbit heart muscle cells. Specifically, low levels of potassium caused increased internalization and degradation of the channels. Similarly, low levels of potassium in culture medium decreased levels of the human counterpart, HERG, in cell lines. These data provide insight into how a drop in levels of potassium in the blood can cause sudden cardiac death.


Story Source:

The above story is based on materials provided by Journal of Clinical Investigation. Note: Materials may be edited for content and length.


Journal References:

  1. Kruse et al. Impaired endocytosis of the ion channel TRPM4 is associated with human progressive familial heart block type I. Journal of Clinical Investigation, 2009; DOI: 10.1172/JCI38292
  2. Guo et al. Extracellular K concentration controls cell surface density of IKr in rabbit hearts and of the HERG channel in human cell lines. Journal of Clinical Investigation, 2009; DOI: 10.1172/JCI39027
  3. Gail A. Robertson. Endocytic control of ion channel density as a target for cardiovascular disease. Journal of Clinical Investigation, 2009; DOI: 10.1172/JCI40427

Cite This Page:

Journal of Clinical Investigation. "Abnormal Heartbeats Caused By Changes In Ion Channel Density." ScienceDaily. ScienceDaily, 28 August 2009. <www.sciencedaily.com/releases/2009/08/090825085530.htm>.
Journal of Clinical Investigation. (2009, August 28). Abnormal Heartbeats Caused By Changes In Ion Channel Density. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2009/08/090825085530.htm
Journal of Clinical Investigation. "Abnormal Heartbeats Caused By Changes In Ion Channel Density." ScienceDaily. www.sciencedaily.com/releases/2009/08/090825085530.htm (accessed July 23, 2014).

Share This




More Health & Medicine News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Courts Conflicted Over Healthcare Law

Courts Conflicted Over Healthcare Law

AP (July 22, 2014) — Two federal appeals courts issued conflicting rulings Tuesday on the legality of the federally-run healthcare exchange that operates in 36 states. (July 22) Video provided by AP
Powered by NewsLook.com
Why Do People Believe We Only Use 10 Percent Of Our Brains?

Why Do People Believe We Only Use 10 Percent Of Our Brains?

Newsy (July 22, 2014) — The new sci-fi thriller "Lucy" is making people question whether we really use all our brainpower. But, as scientists have insisted for years, we do. Video provided by Newsy
Powered by NewsLook.com
Scientists Find New Way To Make Human Platelets

Scientists Find New Way To Make Human Platelets

Newsy (July 22, 2014) — Boston scientists have discovered a new way to create fully functioning human platelets using a bioreactor and human stem cells. Video provided by Newsy
Powered by NewsLook.com
Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) — New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins