Figure 2.

Quantitative determination of the mRNA expression levels of various 5-HT receptors in the sling and clasp fibers of the LES and circular muscle strips from the esophagus and stomach. Bar chart showing the relative mRNA expression levels of the various 5-HT receptors normalized against β-actin. There were significant differences between the 5-HT receptor subtypes in the same muscle strip (P<0.05), but no significant differences for each subtype across various muscle strips (P>0.05). 5-HT, serotonin; LES, lower esophageal sphincter; IOD, integrated optical density; E, circular muscle strips of esophagus; S, sling fibers; C, clasp fibers; G, stomach.