Demonstration of rat preprotachykinin A mRNA in the rat trigeminal ganglion by in situ hybridization histochemistry

The localization of gamma-preprotachykinin A mRNAs in the rat trigeminal ganglion was demonstrated by in situ hybridization histochemistry using the 32P and 35S labelled gamma-preprotachykinin A complementary DNA. In situ hybridization using 32P allowed shorter exposure times, whereas higher resolution of the hybridization signal on both film and emulsion autoradiograms was obtained using 35S. Preprotachykinin A mRNA detected by the gamma-preprotachykinin A probe was localized in about 15 per cent of the trigeminal ganglion cells, most of which were small or medium sized. Immunohistochemical studies using anti-substance P antibodies demonstrated that 15-20 per cent of total trigeminal ganglion cells were positive. These cells were small or medium sized. The result of immunohistochemistry coincided well with that of in situ hybridization histochemistry. The present study showed that the cellular localization of preprotachykinin A mRNA could be analysed by in situ hybridization histochemistry.