Fig. 5.

Evidence of functional selectivity between measures of IP accumulation and ERK1/2 phosphorylation in WT MEFs. A, relative rank orders of efficacy (E_max, 5-HT set to 100%) were significantly altered between measures of IP accumulation (■) and ERK1/2 phosphorylation () for 5-HT_2A agonists in WT MEFs. Statistical ranking of relative E_max values was performed via one-way ANOVA and Tukey-Kramer multiple comparison post-tests in which agonists were assigned to statistically homogeneous groups (designated “a” through “f” in Table 4, labeled bars). Significant differences in rank order were denoted by changes in group membership, and agonists with nonoverlapping group assignments were considered to be significantly different. Values represent the mean of four to five independent experiments performed in duplicate. B, the relative efficacies of MK212 and m-CPP were reversed between measures of IP accumulation (■) and ERK1/2 phosphorylation () in WT MEFs (∗, significantly different from MK212, p < 0.05). Labeled bars represent statistically homogeneous groups (designated “a” through “f” in Table 4). C, concentration-response curves showing the relative abilities of MK212 (■) and m-CPP (○) to stimulate IP accumulation via 5-HT_2A receptors in WT MEFs. Relative E_max values were significantly different (p < 0.05). Values represent the mean ± S.E.M. of four to five independent experiments performed in duplicate. D, concentration-response curves showing the relative abilities for MK212 (■) and m-CPP (○) to stimulate ERK phosphorylation via 5-HT_2A receptors in WT MEFs. Relative E_max values were significantly different (p < 0.05). Values represent the mean ± S.E.M. of four to five independent experiments performed in duplicate.