Figure 3

The effect of SKF 81297 (D1/D5 dopamine receptors agonist) on TTX-R sodium current was antagonized by SCH 23390 and EEDQ. A) Collected results showing the effect of 10 μM SKF 81297 on TTX-R sodium current applied either alone (black circles), or in combination with 3 μM SCH 23390 (blue squares), or 20 μM EEDQ (red triangles), or 100 μM EEDQ (green diamonds). B) The inhibitory effect of 10 μM SKF 81297 on the relative peak of TTX-R sodium current was reduced from 0.63 ± 0.08 (n = 22) when applied without the antagonist (black bars) to 0.83 ± 0.04 (n = 8, one-way ANOVA, followed by post-hoc Dunnett analysis **p < 0.01) when applied on DRG neurons incubated for 15 min with 3 μM SCH 23390 (blue bars); to 0.79 ± 0.06 (n = 6, one-way ANOVA, followed by post-hoc Dunnett analysis **p < 0.01) when applied on DRG neurons incubated for 30 min with 20 μM EEDQ (red bars); to 0.92 ± 0.07 (n = 9, one-way ANOVA, followed by post-hoc Dunnett analysis, **p < 0.01) when applied on DRG neurons incubated for 30 min with 100 μM EEDQ (green bars).