Fig 3. [Ca²⁺]_i oscillations in acinar cells upon stimulation with a ramp of ACh concentrations.

(A) OGB-1 loaded acinar cells in a tissue slice. Scale bar 20 μm. (B) [Ca²⁺]_i oscillations shown here belong to the acinus marked with thin broken line and the corresponding number in (A). At the beginning and end of the protocol, extracellular solution (ECS) was used (see Materials and Methods). On average, after stimulation with 100 μm ACh, a biphasic [Ca²⁺]_i response with a rise in basal [Ca²⁺]_i level was seen in 98.5% of acinar cells. Note that in cell 3, spontaneous [Ca²⁺]_i activity was observed prior to stimulation, whereas cells 1&2 lacked spontaneous activity.