Problems in Calcium Exchange
Identification, at the molecular level, of the Ca binding sites within the sarcolemmal membrane. The anionic phospholipids seem to be the prime candidates.
Localization of the binding sites vis-a-vis inner or outer portion of the sarcolemma.
Development of specific probes for the anionic phospholipids so that phospholipid-Ca interaction can be correlated with contractile function in the whole cell.
The role of membrane fluidity in the determination of Ca movements. For example, the effect of alteration of cholestrerol/ phospholipid ratio.
Development of realistic physical concepts for control of movement of Ca from binding sites to transmembranous channels or carriers.
Establishment of the discrete points of action of various excitation-contraction uncouplers, e.g., cations, calcium blocking drugs.