Figure S1 - Action Potential-Evoked Calcium Release Is Impaired in Single Skeletal Muscle Fibers from Heart Failure Patients

The transverse tubular system in live fibers from control and HF individuals. Muscle bundles dissected from biopsies obtained from control individuals (A) and HF patients (B) were stretched to a sarcomere length similar to that in the electrophysiological experiments and pinned down on a Sylgard bottomed dish. The fibers were stained with di-8-ANEPPS and imaged using a two-photon laser scanning microscope (Biorad Radiance 2000). The dye was excited with a 920 nm laser beam, and the emission was collected using a dichroic/band-pass combination of 506 nm/620–650 nm. It can be seen in the optical section in A that, as previously described for other mammalian fibers, di-8-ANEPPS clearly demonstrate the regular double row pattern of the transverse tubular system. The surface membrane can also be seen at the right upper part of the image. The image in B demonstrate that the transverse tubular system of fibers from HF patients is indistinguishable from that of control fibers. The scale represent 15 µm in both images.
(EPS)