Fig. 6.

P2Y receptor activation did not modulate secretion evoked by flash photolysis of caged Ca²⁺. A, C_m traces (top trace) and corresponding [Ca²⁺]_i (bottom trace) recorded in response to the first flash (80 J, 500 μsec) given ∼240 sec after establishing the whole-cell configuration (left panel) and a second flash of the same intensity given 120 sec later to the same cell (right panel).B, Kinetic analysis of two example ΔC_m recorded in response to the first flash after establishing the whole-cell configuration, either under control conditions (○) or in the presence of 100 nm2-MeSATP (●). For clarity of illustration, only every third point is shown. The solid line drawn through the data represents a double-exponential fit obtained using theC_m point immediately after the UV flash and the plateau level as limits. The mean time constants displayed are for both control conditions (n = 5) and in the presence of 100 nm 2-MeSATP (n = 4).