The systemic circulation offers larger resistance to the blood flow than the pulmonary system. Consequently, the left ventricle (LV) must pump blood with more force than the right ventricle (RV). The question arises whether the stronger pumping action of the LV is due to a more efficient action of left ventricular myosin, or whether it is due to the morphological differences between ventricles. Such a question cannot be answered by studying the entire ventricles or myocytes because any observed differences would be wiped out by averaging the information obtained from trillions of myosin molecules present in a ventricle or myocyte. We therefore searched for the differences between single myosin molecules of the LV and RV of failing hearts In-situ. We show that the parameters that define the mechanical characteristics of working myosin (kinetic rates and the distribution of spatial orientation of myosin lever arm) were the same in both ventricles. These results suggest that there is no difference in the way myosin interacts with thin filaments in myocytes of failing hearts, and suggests that the difference in pumping efficiencies are caused by interactions between muscle proteins other than myosin or that they are purely morphological.

Document Type


Publication Date


Notes/Citation Information

Published in Frontiers in Physiology, v. 8, 732, p. 1-11.

© 2017 Duggal, Requena, Nagwekar, Raut, Rich, Das, Patel, Gryczynski, Fudala, Gryczynski, Blair, Campbell and Borejdo.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

Digital Object Identifier (DOI)


Funding Information

This work was supported, in whole or in part, by the National Institutes of Health R01 AR048622 (to JB) and R01HL090786 (to JB and Dr. Danuta Szczesna-Cordary), R01EB12003 (to ZG) and by the Bridge Grant # RI6127 from UNTHSC.

Related Content

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fphys.2017.00732/full#supplementary-material

data sheet 1.pdf (174 kB)
Data Sheet 1