Fig. 4.

ATP evokes nondesensitizing whole-cell currents in acutely dissociated dorsal horn neurons. A, A 2 sec application of ATP evoked a small, nondesensitizing, inward current in a neuron obtained from a P8 animal. B, The ATP-evoked current shows inward rectification in a different neuron from the same preparation. The current–voltage curve for the ATP-evoked current was constructed by applying a voltage ramp during the agonist application. Inward rectification of theI–V relationship is evident over the voltage range between −85 and −20 mV.