Fig. 4.
Immunoblot analysis of agonist-mediated ERK1/2 phosphorylation in FlpIn HEK293 5-HT2B receptor-expressing cells. A, representative immunoblots probed with anti-phospho-ERK1/2 or anti-total-ERK1/2 antibodies as indicated. B, image densitometry of immunoblot scans in A to quantify phospho-ERK1/2 content in cell lysates. Immunoreactivity for phospho-ERK1/2 (i.e., mean pixel intensity per region of interest that contained the p42 and p44 bands, minus the background) was measured for each sample. Blots were then stripped and reprobed for total-ERK1/2 and analyzed as before. The phospho-ERK1/2 immunoreactivity for each sample was normalized to its total-ERK1/2 immunoreactivity. The normalized phospho-ERK1/2 immunoractivity elicited by 5-HT (measured on each gel) was set to 100%. SB, SB-206,553 pretreatment.