Key Points
- The central aim is to explore how sarcomere lengths and coupling behave under applied strains in cardiac myocytes.
- Used chemically skinned myocytes from adult rat hearts attached to double-barreled pipettes to apply strain.
- Measured variation in sarcomere length and striation registration across myocyte domains during stretching.
- Most sarcomere domains showed proportional increases in length upon stretch, maintaining initial length differences.
- Striation mis-registration of up to 0.20 microns occurred between domains after stretch, indicating varied coupling.
- Concluded that myocytes are not rigid, but consist of semi-independent functional domains connected by a cytoskeletal framework.
Structured PICO
PPopulationChemically skinned cardiac myocytes isolated from adult rat hearts
IInterventionGradient of applied strain across the width of the cell (passive stretch)
CComparatorRest lengths (unstretched state)
OOutcomeSarcomere length and striation registration behaviorsurrogate
Cardiac myocytes function as composite structures with semi-independent domains tethered by the cytoskeletal intermediate filament lattice, allowing for a non-linear relationship between sarcomere length and strain.