FIGURE 6.
No synergistic or additive effects on intracellular calcium signaling in cells co-expressing the GHS-R1a and the 5-HT2C receptor. A and B, co-expression of the GHSR1a receptor (A) or the 5-HT2C receptor (B) as EGFP or RFP fusion proteins yields similar ligand-mediated calcium increases. C–E, no synergistic or additive effects are observed in cells co-expressing the GHS-R1a receptor and the 5-HT2C-RFP receptor (C), cells stably expressing the unedited 5-HT2C-INI (D), or the partially edited 5-HT2C-VSV (E) receptor transduced with the GHS-R1a-RFP receptor, following treatment with 10 or 100 nm 5-HT (light gray bars), with 10 or 100 nm ghrl (dark gray bars), or with a combination of 10 nm both (black bars). The data represent the means ± S.E. of an experiment performed in triplicate for each concentration point with the intracellular calcium increase depicted as a percentage of maximal calcium increase as elicited by control (3% FBS). Statistical significance within the 10 nm data sets was analyzed using two-way ANOVA followed by Bonferroni multiple comparison test; statistically significant effects of combination treatment (10 nm serotonin, 5-HT, + 10 nm ghrl) were compared with 10 nm 5-HT alone at p < 0.01 (a) or with 10 nm ghrl alone at p < 0.001 (b).