Adult mammalian ventricular myocytes, the preparation discussed in this article, are extremely fragile and sensitive to seemingly minor alterations in isolation conditions or solutions. Thus, the importance of taking extreme care in the isolation of ventricular myocytes for whole-cell recording cannot be overstated. We have also applied this method, on occasion, to rats as young as 10-12 days and to adult mice and rabbits. However, we try to avoid using cultured cardiac myocytes, since we have found that the electrophysiology of cells is altered within hours of culturing. Similar methods for the isolation of adult ventricular myocytes for a variety of purposes are described in several other articles in this Help section.
Speed is of the essence.
The heart is weighed in the chilled Isolation Solution and gently squeezed to remove blood. The cells are then centrifuged again at 60 x g for 3 min and then resuspended a final time in Storage Solution. We have recorded other currents from these and other cells using different solutions and voltage protocols. Coating the pipettes with a hydrophobic elastomer is not necessary for recording these relatively large currents in adult mammalian cells. A suspension of myocytes is placed into a bath chamber on the microscope stage and allowed to settle for a few minutes in order to attach lightly to the glass bottom of the chamber.