Figure 2.

Changes in [Ca²⁺]_i in HCD-cells evoked by mechanical stimulation. In the presence of extracellular calcium (a control), mechanical stimulation of an individual cell, within a cluster, elicits an increase in [Ca²⁺]_i. The rise in [Ca²⁺]_i rapidly propagates into coupled cells. Removal of extracellular calcium (b) reduces the basal-to-peak change in mechanically evoked [Ca²⁺]_i, but does not negate the response. Depletion of Ca²⁺ stores via preincubation of the Ca²⁺-ATPase inhibitor, thapsigargin (Tg 1 μM; 30 min, (c) in the absence of extracellular calcium, completely prevents mechanically evoked changes in [Ca²⁺]_i. (d) shows mean basal-to-peak data from several experiments (n = 4) and indicates a role for both intra- and extracellular calcium in mediating mechanically evoked Ca²⁺-signalling in HCD-cells. Data is represented as an estimated change in [Ca²⁺]_i recorded as a ratio of 340/380 nm excitation for fura-2. Statistical analysis ((d); P < 0.01 control versus Ca²⁺-free and P < 0.001 control versus Ca²⁺-free + Tg).