Influence of some variables in the Triton X-100 method of skinning the plasmalemmal membrane from guinea pig trachealis muscle.

Electron microscopy showed that the process of skinning guinea pig trachaelis muscle using Triton X-100 destroys the plasma membranes and causes some retraction of the myofibrils toward the center of the cells. Seven days represents an optimal period for the low temperature storage of the skinned fibers. Increasing the imposed tension from 0.25 to 1.0 g reduces the size of the maximal response to Ca2+. Some sensitization of the skinned fibers to Ca2+ follows the construction of the initial Ca2+ log concentration-response curve. Exogenous calmodulin is not essential for Ca2+-induced tension development and, at 20 degrees C, does not potentiate Ca2+. Useful economy can be achieved without compromising Ca2+ sensitivity or responsiveness by using ATP (a component of the relaxing solution) of purity 99% rather than of 99-100%.