Free radicals are molecules that react readily with other substances in the body, and this can have negative effects on health in certain circumstances, through the damage caused to cells. Free radicals can be counteracted by substances known as âantioxidantsâ, which are common ingredients in many dietary supplements. The idea that free radicals are generally dangerous and must be counteracted is, however, a myth, according to scientists who have conducted a new study of the role that free radicals play in heart physiology.
âAs usual, itâs a case of everything in moderation. In normal conditions, free radicals act as important signal substances, but very high levels or long-lasting increases can lead to diseaseâ, says Professor HĂ„kan Westerblad, who has led the study.
When the body is subject to different types of stress, the sympathetic nervous system stimulates receptors known as beta-adrenergic receptors on the surface of heart muscle cells. This leads to several changes inside the cells, one of which is the phosphorylation of proteins. This leads to the contractions of the cells becoming stronger and the heart beats with greater force.
In the current study, the scientists show that stimulation of the beta-adrenergic receptors also leads to increased production of free radicals in the mitochondria of the cells, and these then contribute to stronger contractions of the cells. When the scientists exposed the cells to antioxidants, a major part of the effect of beta-adrenergic stimulation of the heart muscle cells disappeared.
The results reveal a previously unknown regulatory mechanism of the force production in the heart, and may lead to a better understanding of various types of heart deficiency.
âFree radicals play an important role, since they contribute to the heart being able to pump more blood in stress-filled situationsâ, says HĂ„kan Westerblad. âOn the other hand, persistent stress can lead to heart failure, and chronically increased levels of free radicals may be part of the problem here.â
Publication âMitochondrial production of reactive oxygen species contributes to the beta-adrenergic stimulation of mouse cardiomycytesâ, Daniel C Andersson, JĂ©rĂ©my Fauconnier, Takashi Yamada, Alain Lacampagne, Shi-Jin Zhang, Abram Katz & HĂ„kan Westerblad, The Journal of Physiology, online 28 February 2011, paper issue 1 April 2011.
Caption: HĂ„kan Westerblad, photo credit to Stefan Zimmerman
For more information, please contact:
Professor HĂ„kan Westerblad
Department of Physiology and Pharmacology
Tel: +46 8 5248 7253 or +46 (0)70 753 5456
E-mail: hakan.westerblad@ki.se
28 February, 2023 - Karolinska Institutet
Following a successful pilot study, an online anonymous treatment program aimed at reducing child sexual abuse by providing treatment to individuals who exhibit sexual urges towards children is being launched across the EU. It is now available in Swedish, German, and Portuguese as well as in an updated English version. The treatment program, which has […]
29 April, 2021 - Karolinska Institutet
Researchers at Karolinska Institutet and the Public Health Agency of Sweden have studied newborn babies whose mothers tested positive for SARS-CoV-2 during pregnancy or childbirth. The results show that although babies born of test-positive mothers are more likely to be born early, extremely few were infected with COVID-19. The study, which is published in the […]
27 April, 2020 - Karolinska Institutet
Only about five per cent of the babies born to mothers with hepatitis C are themselves infected by the disease. A possible reason for this low figure is that the babyâs immune system has already destroyed the virus before birth. A new study from researchers at KI and published in the journal Gut reveals clear […]
7 April, 2020 - Karolinska Institutet
People with celiac disease have increased risk of dying prematurely, despite increased awareness of the disease in recent years and better access to gluten-free food. This is according to a new study from Karolinska Institutet in Sweden and Columbia University in the U.S. published in the prestigious journal JAMA. Celiac disease was linked to increased […]
Expertsvar, The Swedish Research Council, Hantverkargatan 11B, Stockholm SWEDENPhone +46(0)8 546 44 000
P.O. Box 1035, SE-101 38 Stockholm, expertsvar@vr.se
Information about cookies will open in a new window
