Fig. 2

Both delayed REOI and PEOI upregulated the 5-HT3B receptor subtype in the Sp5. A Upper panel shows low magnification photograph of 5-HT3B receptor subtype immunostaining in the Sp5 brainstem section of the sham rat. Scale bar, 500 μm. Lower panel shows representative high-magnification photograph of 5-HT3B receptor subtype immunostaining in the area encircled by a white rectangle (ventrolateral region) in the upper panel. Scale bar, 200 μm. B Representative high-magnification photographs showing the co-expression of 5-HT3B receptor subtype with NeuN in the Sp5 in sham, REOI, and PEOI rats. Scale bar, 50 μm. C Semi-quantitative analysis on the ratio of 5-HT3B receptor subtype/NeuN double-positive cells to NeuN-positive cells showed a significant increase in REOI and PEOI rats (n = 3 rats per group, each symbol represents one rat with five measured sections per rat). (D) Semi-quantitative analysis on the area of 5-HT3B receptor subtype showed a significant increase in REOI rats (n = 3 rats per group, each symbol represents one rat with five sections measured per rat). E Semi-quantitative analysis on the mean fluorescence intensity of 5-HT3B receptor subtype showed a significant increase in REOI and PEOI rats (n = 3 rats per group, each symbol represents one rat with five measured sections per rat). F Western blotting illustrated increased expression levels of 5-HT3B receptor subtype in REOI and PEOI rats (n = 5 rats per group). Results represent mean ± SD; one-way ANOVA, followed by Tukey’s multiple-comparison test. 5-HT3B R, 5-HT3B receptor subtype