Characterization of durations of [Ca²⁺]_i oscillations superimposed on the sustained plateau. A

<p>Representative traces of 3 subsequent [Ca²⁺]_i oscillations in 15 cells analyzed in B and C. Scale bar represents 5 seconds. On Y-axes, values represent normalized fraction of the difference between maximum and plateau baseline fluorescence. <b>B</b> Distribution of durations of Ca²⁺ oscillations for 15 subsequent [Ca²⁺]_i oscillations in 15 cells from a single islet presented for individual cells. Note that in every cell, roughly the same range of interval durations is present. The box plot indicated with “All cells” shows the distribution of interval durations pooled for 15 subsequent [Ca²⁺]_i oscillations in 15 cells from the same islet (median = 3.5 s, 1^st quartile = 2.9 s, 3^rd quartile = 4.1 s). The box plot indicated with “All islets” shows the distribution of durations for all [Ca²⁺]_i oscillations in 6 different islets (median = 2.2 s, 1^st quartile = 1.8 s, 3^rd quartile = 3.4 s). <b>C</b> Distribution of durations of [Ca²⁺]_i oscillations for 15 subsequent [Ca²⁺]_i oscillations in 15 cells from a single islet, presented for every individual [Ca²⁺]_i oscillation. Note that the durations vary from one oscillation to another in roughly the same way in all analyzed cells. <b>D</b> Time-variability of the duration of [Ca²⁺]_i oscillations in 6 islets of Langerhans over a period of 120 seconds, shown as the distribution of durations of [Ca²⁺]_i oscillations in four subsequent 30-seconds-long time intervals. For each of the 6 different islets median durations of [Ca²⁺]_i oscillations were calculated for each of the 30-seconds-long time intervals and compared with each other by employing nonparametric Friedmańs analysis of variance. The duration of [Ca²⁺]_i oscillations did not significantly change over the four time intervals.