Immunofluorescence of SNAP-25, SV2A and TRPV1.

<p>1A–1C: SNAP-25-positive neurons were observed in one-week-old DRG cultures, and positive staining was located both in the periphery of the cytoplasm and neuronal processes. The staining pattern did not change except that the number of SNAP-25-positive cells increased with longer culture periods. 1D–1F: Compared with the IF staining of SNAP-25, the positive staining for SV2A was mainly distributed in the cytoplasm and was less highly expressed along neuronal processes until 3 weeks of culture. Moreover, weak and scattered IF positivity for SV2A was observed in nuclei in the cells with shorter culture periods. 1G–1I: Much like SNAP-25, TRPV1 was also expressed in cultured DRG neurons after 1 week of culture. Initially, the positivity mainly appeared around the surface of the cell body. In the 2- and 3-week cultures, the positive immunofluorescence became much stronger. Obvious immunoreactivity for TRPV1 was observed in both the cytoplasm and processes when cells were cultured for up to 3 weeks, especially along the neuronal processes, as shown in the inset in 1I (bar = 50 μm).