Localization of P2X_7 Receptor Immunoreactivity in the Dorsal Root Ganglia of Guinea Pig

摘要

The P2X7 receptor mRNA and proteins in guinea-pig dorsal root ganglia （DRG） were studied by using RT-PCR and immunohistochemistry. The co-localization of P2X7 receptor with four cytochemical markers, the neurofilament protein NF200, S100, substance P and isolectin B4 （IB4） binding glyco-conjugates, were also examined. It was found that P2X7 receptor immunoreactivity （P2X7R-IR） was present mostly in large- and medium-sized DRG neurons （62 %±9 % and 36 %±6 % respectively in all P2X7R-IR neurons）. All the P2X7R-IR neurons were also NF200 and S100 immunopositive. However, in a small number of NF200 or S100 immunopositive neurons no P2X7R-IR was detectable. All the IB4-positive or substance P-immunopositive neurons had no P2X7R-IR. These results demonstrate that P2X7 receptors are expressed in a large subpopulation of DRG neurons and they may play a role in the transduction of specific peripheral sensory signals.