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Fig. 6. Caffeine inhibits TLC-S induced [Ca2+]i responses in permeabilized pancreatic acinar cells. Rat pancreatic acini were resuspended in a permeabilization solution containing 10 µM digitonin. A: permeabilized acini were stimulated with 1 µM inositol (1,4,5)-trisphosphate (IP3). After [Ca2+]i reached a plateau, 20 mM caffeine was added. After 5 min of caffeine exposure (interrupted tracing), permeabilized acini were again stimulated with 1 µM IP3. B: permeabilized acini were incubated for 5 min with vehicle (top trace) or 20 mM caffeine and then stimulated with 180 µM TLC-S. Tracings are representative of 3 independent experiments. C: effect of 20 mM caffeine on the area under the curve of the [Ca2+]i response after stimulation of permeabilized acini with 180 µM TLC-S. The [Ca2+]i response to TLC-S in the absence of caffeine (i.e., in acini incubated with vehicle) was considered as 100%. Values are means ± SE from 3 tracings for the corresponding responses. *P < 0.05 compared with the [Ca2+]i response of acini stimulated by TLC-S in the absence of caffeine.
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