Figure 4. Palonosetron suppresses the ability of 2-Me-5-HT to upregulate CaMKIIα phosphorylation in enterochromaffin (EC) cells.
The isolated EC cells from the least shrew intestine were incubated with the 5-HT3R antagonist palonosetron (1 µM) or its vehicle for 30 min and then the 5-HT3R agonist 2-Me-5-HT (1 µM) was added for the next 30 min. The corresponding antagonist and agonist vehicles were also incubated with EC cells and were used as control. A) The control and treated EC cells were harvested to analyze CaMKIIα phosphorylation (Thr286) using Western blot. n = 3 experiments per treatment group. *P<0.05 vs. vehicle/vehicle control. #P<0.05 vs. vehicle + 2-Me-5-HT. Graph A shows the summarized data and the insets represent the representative Western blot. B) Representative fluorescence images show the immunoreactivity for CaMKIIα (red) and pCaMKIIα (green) in EC cells treated as described in (A) and subjected to immunocytochemistry to determine 5HT3R-mediated CaMKIIα activation in isolated EC cells in vitro. Nuclei of EC cells were shown with DAPI stains. Scale bar, 4 µm.