A method for recording isometric tension development by isolated cardiac myocytes: transducer attachment with fibrin...

The purpose of this study was to develop a method for attachment of single isolated cardiac myocytes to a transducer for recording isometric tension development. Cardiac myocytes were isolated from the hearts of the toad, Bufo marinus or ferrets by enzymatic digestion with collagenase. The method that we used provided a 60-80% yield of Ca++-tolerant cells. A suspension of cells was placed into a superfusion chamber coated with bovine thrombin. Two glass microtools - each attached to a micromanipulator - were brought into proximity with the ends of a single myocyte; one of the microtools was attached to the element of a low-level force transducer. Human fibrinogen was loaded into a fine-tipped glass micropipette mounted on a micromanipulator. Small amounts of fibrinogen were pressure-ejected from the pipette at each junction between the microtool and the end of the myocyte. The fibrin that formed produced a stable attachment of the ends of the myocyte to the microtools. The myocyte could subsequently be stretched and a length-tension curve recorded. We have used this method to record concentration-dependent tension development in response to the Ca++-ionophore, A23187, and potassium depolarization. Our results indicate that fibrin glue may facilitate the study of the mechanical properties of isolated myocytes.