Fig. 2. Increased Ca²⁺ influx enhances the response of the central non-junctional RyRs. The top portion of the figure depicts the experimental protocol. The arrowheads indicate the points at which cells were depolarised. The transformation in the spatial distribution of action potential-evoked Ca²⁺ signals is shown by the change in the ratio of Ca²⁺ signal amplitude in the subsarcolemmal space relative to central regions. The filled circles denote the response of the myocyte from which the inset traces were obtained, and the red diamonds show the mean±s.e.m. from six cells (two each from three rats). The inset panels illustrate the time course and amplitude of the Ca²⁺ signal at subsarcolemmal (black trace) and central (white traces) regions. A pseudo-linescan is shown beneath the traces to illustrate the spatial properties of the recorded Ca²⁺ signals. The yellow trace under the pseudo-linescan image indicates the extent of cellular contraction and the vertical dashed red line, the onset of depolarisation.