Localization of ATP-gated P2X(2) and P2X(3) receptor immunoreactive nervesin rat taste buds

P2X receptors have been suggested to play a role in the transduction of sen sory signals such as pain and sound. In the present study, polyclonal antib odies against P2X(1) to P2X(6) receptors were used to localize P2X receptor s in circumvallate and fungiform papillae of rats. Nerve fibres innervating the taste buds stained intensely with P2X(3) receptor antibodies. P2X, rec eptor-positive nerves were observed in the intra- and subgemmal regions. Th e nerve fibres were also stained with P2X(2) receptor antibodies, but the i ntensity was much lower. The distribution of P2X(2) receptor immunoreactivi ty overlaps with that of P2X(3). These results suggest that ATP might be a neurotransmitter in taste reception cells in the taste buds, where it trans ducts the taste signals to the afferent taste nerves by activating P2X rece ptors at the synapses. This is the first experiment indicating such a role for ATP, although supplementary functional studies are required. NeuroRepor t 10:1107-1111 (C) 1999 Lippincott Williams & Wilkins.