Cardiac Contractile Function
Cardiac Contractile Function - Related Videos
06:22
Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice
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Cited by 14 •
2015
Murine left ventricular papillary muscle can be used to investigate cardiac contractility in vitro. This article describes in detail the isolation and experimental protocols to study cardiac contractile characteristics.
07:32
Analysis of Cardiac Contractile Dysfunction and Ca2+ Transients in Rodent Myocytes
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Cited by 2 •
2022
A set of protocols are presented that describe the measurement of contractile function via sarcomere length detection along with calcium (Ca2+) transient measurement in isolated rat myocytes. The application of this approach for studies in animal models of heart failure is also included.
07:26
Isolation of Functional Cardiac Immune Cells
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Cited by 9 •
2011
This method for isolating functional immune cells from the heart provides an alternative to the conventional methods of collagenase digestion, which causes unwanted immune cell activation, resulting in a decreased responsiveness of these cells. Our method of isolation yields functional cardiac immune cells by avoiding problems associated with enzymatic digestion.
09:05
Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging
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Cited by 25 •
2016
The goal of this protocol is to noninvasively assess cardiac structural and functional changes in a mouse model of heart disease created by transverse aortic constriction, using B- and M-mode echocardiography and color/pulse wave Doppler imaging.
08:08
Measurement of Cytosolic Ca2+ in Isolated Contractile Lymphatics
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Cited by 24 •
2011
We introduce an approach to evaluate the cytosolic Ca2+ concentration in isolated lymphatics to study Ca2+-dependent and Ca2+-sensitizing mechanisms of lymphatic smooth muscle contraction.
FAQs
Electrical excitation links the cell’s signal to mechanical contraction through calcium handling. In cardiomyocytes, excitation promotes calcium entry and release from the sarcoplasmic reticulum, raising cytosolic calcium. The ion then binds troponin, a regulatory protein, and permits actin-myosin cross-bridge cycling. This excitation-contraction sequence converts electrical activity into sarcomere shortening and force generation.
Calcium concentration in the cytosol determines whether contraction can continue. After activation, calcium must be removed from the cytosol so troponin no longer supports actin-myosin interaction and the sarcomere can relax. This transition is essential because relaxation allows cardiac chambers to refill before the next contraction, linking calcium recovery to rhythmic pumping.
Actin-myosin cross-bridge cycling supplies the molecular basis for sarcomere shortening. As many contractile units shorten within cardiomyocytes, the muscle generates force that contributes to chamber pressure. This provides a mechanistic connection between molecular interactions and whole-heart performance, helping researchers relate calcium signaling and contractile activity to blood movement and cardiac output.
A useful analysis follows the pathway from electrical excitation to calcium entry and sarcoplasmic-reticulum release, then to troponin activation, cross-bridge cycling, sarcomere shortening, and calcium removal. Examining these stages separately helps connect cellular events with force, pressure generation, cardiac output, and chamber refilling. The sequence also provides a framework for interpreting altered contractile performance.
Cardiac contractile function is studied in heart-failure research because impaired myocardial performance can affect force generation, pressure production, and cardiac output. Tracking the excitation-calcium-contraction-relaxation sequence helps investigators identify which part of the process is altered. This cellular perspective connects heart failure with consequences for the heart’s essential pumping role.
The pathway provides a basis for studying drug action and therapies intended to improve myocardial performance. Investigators can consider whether an intervention affects electrical excitation, calcium entry or release, troponin-dependent activation, cross-bridge cycling, or calcium removal. Relating the affected step to contraction and relaxation helps place treatment effects within the broader biology of cardiovascular disease.