Figure 1

Effects of ATP and αβmeATP on mEPSCs recorded from lamina I neurons of rat spinal cord slice preparations A. The image on the left shows a spinal cord slice section viewed under a 4X objective. An electrode is shown to the left side of the tissue section. The tip of the electrode is in lamina I. Scale bar: 100 μm. The image in the middle shows the tissue section viewed under a 40X objective with the IR-DIC system. Near the center of the field is a lamina I neuron (arrow indicated) that is patched with an electrode. The cell is on the border between white matter and gray matter. White matter (W), lamina I (I), and lamina II (II) are indicated. Lamina I region is outlined with two dash lines. Scale bar: 10 μm. The drawing on the right indicates the locations of all neurons recorded in this study. B. Representative traces show mEPSCs at the basal level (control) and following the application of 100 μM ATP. The graph on the right shows cumulative probability histogram of inter-event intervals in the same neuron. The inter-event intervals, which reflect the changes of mEPSC frequency, were significantly shifted following the application of 100 μM ATP (P < 0.01, Kolmogorov-Smirnov test). C. The experiment was the same as B except 100 αβmeATP was tested. The inter-event intervals were significantly shifted following the application of 100 μM αβmeATP (P < 0.01, Kolmogorov-Smirnov test). D. The bar graph shows pooled results from experiments represented in B and C. Both ATP (n = 13) and αβmeATP (n = 14) increased mEPSC frequency without affecting mEPSC amplitude. E. Effects of capsaicin (2 μM) on mEPSCs in 8 cells that were tested for ATP and αβmeATP in D. The scale is in logarithm. Data represent Mean ± SEM, *p < 0.05, **p < 0.01, compared with controls, paired Student's t-test.