Doctors hope the study of communication between the nervous and cardiovascular systems will facilitate the creation of treatments for heart problems.
Researchers at Thomas Jefferson University, in the United States, first mapped the neurons of a human heart and recreated them in a 3D scheme. The finding was shared in an article on iScience last Tuesday (26).
The normal functioning of the heart is maintained by the brain through an intricate network of nerves. In addition, the organ has its own intracardiac nervous system (ICN) to monitor and correct any local disturbances in communication between the body’s systems.
Communication errors between the heart and the brain result in heart disease, including heart attacks, sudden cardiac death, and problems with blood supply. Until now, little was known about the functioning of ICN, which made it difficult to create treatments for these problems.
“The ICN represents a big void in our understanding that falls between neurology and cardiology,” said James Schwaber, one of the study’s authors, in a statement. “Our goal was to bridge that gap by providing an anatomical framework of the ICN and a foundation to understand its role in heart health.”
Thanks to technology, the researchers were able to map the nerves of the heart, showing the complexity of the ICN and revealing even neurons that were still unknown. The nerve structures of the organ are found in a coherent band of clusters at the top of the heart, where veins and arteries enter and exit, but they also extend along the left atrium, the back of the heart.
In addition, they are positioned close to certain important cardiac structures, such as the sinoatrial node, one of the specialized tissues responsible for generating and conducting electrical impulses in the heart.
“We know the sinoatrial atrial node is important in creating the heart rate or pace,” said Jonathan Gorky, co-author of the research. “Seeing the clustering of neurons around it was something we had always suspected but had never known for sure. It was really interesting to see the physical evidence of the ICN’s function and the precise distribution of the neurons in relationship to the anatomical structures of the heart.”
Analysis of the gene expression of individual neurons also pointed to a previously unknown diversity of molecules. “We found that there are several different types of neuromodulators and receptors present,” explained Raj Vadigepalli, senior author of the study. “This means that we don’t just have neurons in the heart that shut on and off activity, but also those that can fine-tune the activity of the ICN.”