P2X3R-mediated ATP currents in Dil-labeled DRG neurons. A. An example of a Dil-labeled DRG neuron (Left). A phase image of the same DRG neuron is shown on the right. Examples of fast-inactivating P2X3R-mediated ATP currents evoked in hindpaw-innervated Dil-labeled neurons isolated from L4-6 DRGs of control (B) and STZ-treated (C) rats. The solid line above each trace indicates the period of an application of 20 μM ATP or ATP+TNP-ATP (100 nM). The membrane was held at -60 mV. TNP-ATP completely blocked the fast-inactivating ATP currents obtained from both control and STZ -treated rats. The block was partially reversed following a 3 min washout of TNP-ATP.