Lying between single cell and whole heart experimental studies, intact papillary muscle isolated from hearts offers unique advantages. Unlike single isolated myocytes, which represent the smallest fully functional model system, intact papillary muscle can be used to study cardiac function within a multicellular context and an intact 3-dimensional myofilament lattice. And unlike whole heart studies, the contractile characteristics of papillary muscle can be evaluated independently of extrinsic factors such as vascular tone. Papillary muscle also allows measurements too difficult or impossible to perform in whole hearts. Similarly, unlike skinned preparations, intact muscle preparations allow for simultaneous detection of force production and intracellular calcium dynamics.
The new IonOptix Papillary Muscle Chamber has been designed to facilitate simultaneous measurements of both quantitative fluorescence and force development. Intact ventricular papillary muscle or other excitable muscle tissue is attached between a robust force transducer and programmable length controller. Chamber fluid flow allows for temperature control and continuous oxygenation of tissue, while the specialized force transducer allows for electrical excitation directly through platinum hooks attached to the muscle preparation. The platinum allows for electrical conductance and are inert, therefore there is no electrolysis or disruption of biology.
This chamber is designed to be used for excitable muscles up to 2 cm in length:
- Cardiac papillary muscle of many species (mouse, rat, rabbit, cat, dog, pig)
- Cardiac endocardial strips or trabeculae (mouse, rat, rabbit, cat, dog, pig
- Cardiac epicardial strips (mouse, rat, rabbit, cat, dog, pig, human
- Skeletal muscles, e.g., soleus, extensor digitorum longus (EDL), gastrocnemius, cremaster (mouse, rat)