Fig. 7.

P2Y receptor activation inhibited ΔC_m evoked by a train of depolarizing pulses. A, Superimposed C_mtraces recorded from a single cell in response to a train of twenty 20 msec depolarizing pulses to +20 mV from −90 mV. A control train (top trace) evoked an appreciable change inC_m, and superfusion of 2-MeSATP (bottomtrace) inhibited the ΔC_m in response to a subsequent train. Gaps in the traces and schematic in the top panelindicate timing of the pulses. B, Summary of the mean ± SEM inhibition of integrated Ca²⁺ entry (▿) and ΔC_m (▴) by 2-MeSATP for each pulse in the train of depolarizations. Significant differences between inhibition of integrated Ca²⁺ entry and ΔC_m changes are shown: ***p < 0.005; *p < 0.05 (n = 23). C, Plot of the mean Ca²⁺-dependence of ΔC_mmeasured in response to a train of depolarizing pulses in the absence (♦) and presence (○) of 2-MeSATP (n = 23). Error bars are omitted for clarity.