Figure 3.

5-HT₇ receptor-induced SRE activation does not depend on PKA activation. A, NIH3T3 cells were transfected with 100 ng of 5-HT₇ receptor cDNA, 50 ng of pSRE.L, and 50 ng of pCMV-β-gal. After serum starvation, cells were treated with 10 μm PKI for 6 h, and SRE activity wasdetermined.B, 5-HT₇ receptor-induced CREB activation depends on PKA activation. NIH3T3 cells were transfected with 100 ng of 5-HT₇ receptor cDNA or empty pcDNA3 vector together with 75 ng of pFR-luciferase (reporter plasmid) and 4 ng of pFA2-CREB (fusion trans-activator plasmid) for assessment of CREB activation. After serum starvation, cells were treated with 10 μm PKI for 6 h and then CREB activity was determined. Data points represent the means ± SEM from at least three independent experiments. A statistically significant difference between values is indicated (^*p < 0.01).