Stimulus-secretion coupling in isolated islets.

<p>(<b>A</b>) Measurements of [Ca²⁺]_i in intact wt (upper) and CgB-ko (lower) islets, representative of 25 and 27 experiments, respectively. The glucose concentration (G) was changed from 1 to 5 and later to 15 mM during the recording, as indicated. Note that the Ca²⁺-signal lags by >2 min, reflecting the time β-cell need to metabolize the sugar. (<b>B</b>) Whole-cell Ca²⁺-currents elicited by voltage-clamp depolarizations (50 ms from −70 mV to −40, −20, 0 and +20 mV) in β-cells on the periphery of intact isolated wt (left) and CgB-ko (right) islets, as indicated. (<b>C</b>) Current-voltage (IV) relationships in wt (black) CgB-ko (white) cells, from analysis of the peak currents in recordings as in B. (<b>D</b>) Whole-cell capacitance recordings (ΔC_m, lower) elicited by trains of depolarizations from −70 to 0 mV (top) in β-cells on the periphery of isolated wt (left) and CgB-ko (right) islets. (<b>E</b>) Analysis of the increase in whole-cell capacitance evoked by each depolarization (ΔC_m,_n–ΔC_m,_n−1) and plotted against time; wt (black) and CgB-ko (white).