Identification and Characterization of ZEL-H16 as a Novel Agonist of the Histamine H3 Receptor
Figure 7
Phosphorylation of ERK1/2 induced by ZEL-H16 in H3R-expressing HEK-293 cells.
A, time-dependent phosphorylation of ERK1/2 induced by histamine or ZEL-H16. Following 3 h of serum starvation, cells were treated with 1 µM histamine or ZEL-H16 for the indicated time period and cell lysates were analyzed for phosphorylated ERK (p-ERK) and total ERK (ERK) protein levels. Signals were quantified by densitometric image analysis and p-ERK was normalized to a loading control (ERK). The signal at each point is expressed as the percentage of the maximal p-ERK signal induced by histamine. A statistical analysis between ZEL-H16 and histamine for each time point in the kinetic graph was done using a t-test (PRISM software) (*p<0.05; **p<0.01). B, Concentration-dependent phosphorylation of ERK1/2 induced by histamine or ZEL-H16. After serum starvation, cells were incubated with increasing concentrations of ZEL-H16 or histamine (10 nM to 100 µM) and cell lysates were analyzed for p-ERK and ERK levels. Concentration -dependent phosphorylation signals were quantified by densitometric analysis and p-ERK levels were normalized to total ERK levels. The signal at each point is expressed as the percentage of the maximal p-ERK signal induced by histamine. C, The phosphorylation of ERK1/2 induced by ZEL-H16 could be entirely abolished by co-incubation with H3R antagonist thioperamide (***p<0.001). Data represent the mean ±SE of three independent experiments.