Study: Free Radicals Regulate Heart Beat

STOCKHOLMNew research from scientists at the Karolinska Institutet studying the role that free radicals play in heart physiology suggests the fear of free radicals is exaggerated, and they actually act as signal substances that cause the heart to beat with the correct force.

The findings, published in the Journal of Physiology, debunk traditional thinking that free radicals have negative effects on health by damaging cells and must be counteracted by antioxidants.

"As usual, it's 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 disease", said lead author Håkan Westerblad.

Researchers showed that stimulation of the beta-adrenergic receptors also leads to increased production of free radicals in the mitochondria of the cells that 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 revealed 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.

"Free radicals play an important role, since they contribute to the heart being able to pump more blood in stress-filled situations", Westerblad said. "On the other hand, persistent stress can lead to heart failure, and chronically increased levels of free radicals may be part of the problem here."