Figure 2

Effect of D1/D5 and D2 dopamine receptor agonists on TTX-R sodium current. A) In a small DRG neuron (diameter ≤ 25 μm), 10 μM SKF 81297 (D1/D5 dopamine receptors agonist) reduced the relative peak of TTX-R sodium current from 0.97 after 5 min in control to 0.51 after 15 min in SKF 81297. Inset: representative TTX-R sodium current traces recorded after 5 min in control (trace 1), after 15 min in 10 μM SKF 81297 (trace 2), and after 5 min washout (trace 3). B) Collected results showing the effect of 10 μM SKF 81297 on the relative peak of TTX-R sodium current. C) The relative peak of TTX-R sodium current was reduced from 0.99 ± 0.02 after 5 min in control to 0.63 ± 0.08 (n = 22, paired t-Test, **p < 0.01) after 15 min in 10 μM SKF 81297. D) In a small DRG neuron, 20 μM quinpirole (D2 dopamine receptor agonist) caused only a little change on the relative peak of TTX-R sodium current from 0.97 after 5 min in control to 0.94 after 15 min in 20 μM quinpirole. E) Collected results showing the effect of 20 μM quinpirole on the relative peak of TTX-R sodium current. F) The relative peak of TTX-R sodium current was reduced from 0.99 ± 0.01 after 5 min in control to 0.94 ± 0.04 (n = 5, paired t-test, p = 0.065) after 15 min in 20 μM quinpirole.