A, example traces of α7 nAChR responses elicited by PHA543613 (100 μm) in PFC layer 1 cortical neurons showing responses under control, SKF 83822 and combined SKF 83822 and KT-5720 conditions. B, there was a significant decrease in α7 nAChR responses in neurons treated with the D1/D5 dopamine receptor agonist SKF 83822 (n = 7) as compared to control (n = 8) (P = 0.03, t test with Bonferroni correction). Meanwhile the PKA inhibitor KT-5720, when co-applied with SKF 83822, blocked any effect of the SKF compound so that the α7 nAChR responses with KT-5720 (n = 6) were significantly elevated as compared to SKF 83822 alone (n = 7) (P = 0.04, t test with Bonferroni correction). C, we verified our results using another D1/D5 dopamine receptor agonist. The D1/D5 dopamine receptor agonist SKF 81297 (n = 19) also resulted in a significant inhibition of α7 nAChR currents as compared to control (n = 16) (P = 0.02, Wilcoxon rank sum test).