Figure 3.

P2Y₂ mRNA, but not P2Y₁ mRNA, is coexpressed with TRPV1 mRNA in DRG. A, PCR amplification of P2Y₁ (a) and P2Y₂ (b) cDNA fragments from the RNAs of mouse DRG neurons. The expected sizes of the DNA fragments for mouse P2Y₁ and P2Y₂ are 651 and 781 bp, respectively. N, Negative control. B, Coexpression of TRPV1 mRNA with P2Y₁ and P2Y₂ mRNAs in rat DRG neurons. Double in situ hybridization histochemistry was performed on the sections. b and d are dark-field photomicrographs of a and c, respectively. The TRPV1 mRNA-expressing neurons were hybridized by a DIG-labeled antisense probe and visualized as DAB staining (brown cells in a and c). The P2Y₁ mRNA-expressing (b) and P2Y₂ mRNA-expressing (d) neurons were hybridized by the appropriate ³⁵S-labeled antisense probe and visualized as clusters of silver grains. p, Positively labeled neurons. Arrowheads indicate P2Y₁ mRNA-expressing neurons that do not express TRPV1 mRNA, whereas arrows indicate the neurons expressing both TRPV1 and P2Y₂ mRNAs.