Figure 5

Effect of ARA290 on cytoplasmic free calcium concentrations ([Ca²⁺]_i) in pancreatic islets isolated from GK rats. (A) Traces represent dynamics in [Ca²⁺]_i changes in islets from placebo-treated rats. (B) Traces represent dynamics in [Ca²⁺]_i changes in islets from rats treated with ARA290. Bars above the traces indicate the duration of stimulation. 3G and 16.7G indicate 3 mmol/L and 16.7 mmol/L glucose, respectively. CCh indicates 0.1 mmol/L carbamylcholine. The displayed traces are representative of 13 traces from the placebo-treated rats (n = 4) and 17 traces from ARA290-treated rats (n = 4). (C-F) Analysis of changes in [Ca²⁺]_i from (A) and (B). (C) Basal [Ca²⁺]_i changes in peak [Ca²⁺]_i values after (D)16.7 mmol/L G, or (E) in response to 0.1 mmol/L CCh in the presence of 16.7 mmol/L G and (F) in response to 30 mmol/L KCl are represented as mean Δ fura-2 ratio ± SEM. *P < 0.05, **P < 0.01, ns indicates no statistical significance. (G-J) Analysis of glucose-stimulated [Ca²⁺]_i oscillation frequency from (A) and (B). (G) Period of [Ca²⁺]_i oscillations >60 s are considered as slow oscillations. Glucose-stimulated slow [Ca²⁺]_i oscillation frequency in islets are shown as average slow [Ca²⁺]_i oscillation period ± SEM, *P < 0.05. (H) Average slow [Ca²⁺]_i oscillation amplitude ± SEM. (I) Period of [Ca²⁺]_i oscillation between 6 and 60 s are considered as fast oscillations. Glucose-stimulated fast [Ca²⁺]_i oscillation frequency in islets are shown as average fast [Ca²⁺]_i oscillation period ± SEM. (J) Average fast [Ca²⁺]_i oscillation amplitude ± SEM.