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. 2003 Mar 1;23(5):1804–1815. doi: 10.1523/JNEUROSCI.23-05-01804.2003

Fig. 6.

Fig. 6.

The effects of 5-HT on the distribution of syntaxin mRNA and protein require activation of the PKA pathway.A, The top micrographs are pseudocolor representations of in situ hybridization signals for syntaxin mRNA in SNs cultured with L7 and fixed 24 hr after 5-HT applied in the presence of KT5720 or chelerythrine. The bottom micrographs are pseudocolor representations of immunocytochemical signals for syntaxin in SNs 24 hr after the same treatments. The accumulation of syntaxin mRNA and protein in the region of the axon hillock is blocked when 5-HT is applied in the presence of KT5720 but not chelerythrine. Scale bar, 25 μm. B,C, The histograms summarize the effects of the two kinase inhibitors on 5-HT producing changes in the distribution of syntaxin mRNA (B) and protein (C). The height of each bar is the mean ± SEM from seven cultures for each treatment in each assay. An ANOVA (two-factor) indicated a significant difference in the signal intensity for syntaxin mRNA (df = 5, 60; F = 81.856;p < 0.001) and protein (df = 5, 60;F = 30.992; p < 0.001). Treatment with 5-HT in the presence of KT5720 resulted in significantly lower expression 24 hr later at positions 3,4, and 5 (4–8 o'clock) of syntaxin mRNA (B) compared with 5-HT in the presence of chelerythrine (F values from 9.484 to 16.333;p < 0.01). Treatment with 5-HT in the presence of KT5720 also resulted in significantly lower expression of syntaxin protein (C) at positions 3,4, and 5 (4–8 o'clock) compared with 5-HT in the presence of chelerythrine (F values from 6.431 to 7.184; p < 0.01).