P2X and TRPV1 immunoreactivity in ganglia and cultures. A, example of P2X3 receptor expression by β-tubulinIII labeled neurons in a fixed ganglion (left; calibration bar = 50 μm). After one day in culture, medium-size neurons that are also labeled by β-tubulinIII are immunoreactive for P2X3 (middle) or TRPV1 (right; calibration bar = 50 μm) receptors. B, percentage of neurons (β-tubulinIII positive) immunoreactive for P2X3, P2X2 and TRPV1 in the ganglion and at different d in culture, for rat (left) and mouse (right; n = 3 animals in all cases). The number of P2X3 and TRPV1 immunoreactive neurons increase significantly after dissection and remain constant in culture, while P2X2 receptor labeled neurons remain unchanged. *: P < 0.05 for indicated pair of histograms. Values at later d in culture are also significantly different from ganglia. C, comparison of TRPV1 receptor immunoreactivity of rat (left) or mouse (right) ganglia. Note larger number of immunoreactive neurons in the rat tissue. Calibration bars = 50 μm.