Figure 3

Properties of ATP evoked currents. Two-electrode voltage clamp recordings at a holding membrane potential of -60 mV were made from oocytes expressing HdP2X. A. Comparison of HdP2X and human P2X₁ receptors. Currents were recorded in response to 100 μM ATP, indicated by bar. HdP2X displays faster current rise and decay times than the human P2X₁ and displays faster recovery from desensitisation between the first and second applications of agonist (applications 5 minutes apart). B. Current voltage relationship of HdP2X. The reversal potential of ATP mediated currents was determined by recording ATP (100 μM, indicated by bar) induced currents at holding potentials ranging from -100 mV to +40 mV with a 5 minute interval between applications. Currents obtained in different oocytes were normalised to the current obtained at -60 mV for each individual cell (n = 6). C. Example currents for the plot depicted in B. D. Concentration response curves for ATP, Bz-ATP and αβ-me-ATP. Mean currents were normalised to the response given by 100 μM ATP (n = 5–7). E and F. Example currents recorded in response to ATP (E) and Bz-ATP (F) (concentrations in μM, agonist application indicated by bar).