Receptor co-localization investigated with double immunofluorescence. Percent of neurons showing double immunoreactivity for pairs of P2X3, P2X2 and TRPV1 as indicated (rat data are on the left while mouse ones are on the right). The "reference" receptor type is taken as 100%. Data from ganglia (about 1,000 neurons) or at different d in culture (about 500 cells per culture) are shown with differently shaded histograms. n = 3 animals for each bar. *: P < 0.05. Values at later d in culture are also significantly different from ganglia. Further details are in the legend to Fig. 3.