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Complete heartbeat control thanks to poisonous jellyfish
What does the poisonous box jellyfish Carybdea rastoni have to do with the human heart? Apparently more than you might think at first glance, because a German research team recently found that certain jellyfish proteins also occur in the human heart muscle, but perform completely different tasks. Through several series of experiments, the team was able to gain new knowledge about heart diseases.
Researchers at the Rheinische Friedrich-Wilhelms-Universität Bonn were able to regulate the heartbeat with the help of a poisonous jellyfish. The scientists discovered so-called G proteins, which are found both in the jellyfish and in the heart muscle. In jellyfish, these proteins are activated by light. After the research team had inserted a certain jellyfish gene into the heart muscle of mice, they were able to control the heartbeat using light pulses. The research results were recently published in the renowned journal "Nature Communications".
Jellyfish eyes and human hearts
In the wild you should avoid the jellyfish Carybdea rastoni. Your tentacles have a strong nettle poison, which can cause severe pain when touched. But the animal has more surprises to offer. It has comparatively sophisticated eyes. If a jellyfish's special brightness receptor is hit by a light beam, stimulating G proteins are activated, which enable the animal to see. Amazingly, the same stimulating G proteins are also found in the human heart.
G proteins regulate the heart rate
This discovery led the Bonn research team to conduct a series of experiments. "With us, stimulating G proteins control the heart rhythm, among other things," explains Professor Dr. Philipp Sasse from the Institute of Physiology at the University of Bonn in a press release on the study results. In humans, the G proteins ensure that the heartbeat speeds up when, for example, physical exertion or the level of adrenaline in the blood increases.
Mice with jellyfish genes
In order to better understand the effect of the G proteins, the researchers introduced a specific jellyfish gene into the heart muscle of mice. As a result, the hearts of the mice had light receptors that could be controlled by irradiation with light. The study team was able to accelerate the rodents' heart rate with the help of an LED light.
New knowledge about cardiac arrhythmias
"This allows us to carry out very specific investigations that would normally not be possible," emphasizes Professor Sasse. In various series of experiments, the researchers initially only specifically stimulated the left atrium of the mouse hearts. As a result, the rodents developed a cardiac fibrillation, which is called atrial fibrillation in humans. If, on the other hand, only the right atrium was stimulated, the pulse rate increased evenly within the frame, as it did with adrenaline. “So different processing of stimuli in the right and left atrium may favor rhythm disorders,” concludes Sasse. The professor and his team would now like to examine this thesis in more detail.
Complex interaction of the heart muscles
In addition, the researchers gained deeper insights into the various processes that interlock in regulating the heartbeat. "If the pulse speeds up, for example, the heart muscles not only have to contract faster and more vigorously, but also relax faster," writes the Bonn team. If this interaction does not work, the amount of blood transported will decrease, even though the heart beats faster. The G proteins play a special role here. According to the study, they ensure that the heart can relax faster after the contraction.
New field of research in heart disease
"Our optogenetic method opens the door to a new research approach," summarizes Sasse. In the following studies the complex processes in the different regions of the heart could be examined much more clearly. (vb)