Figure 1.

Mechanically induced purinergic signaling conveys the magnitude and distance to stimulus. (A) A single Fura2-loaded C2-OB was mechanically stimulated by micropipette, and [Ca²⁺]_i was recorded. Top shows pseudocolored 340/380 Fura2 ratio images. Bottom shows [Ca²⁺]_i recording of mechanically stimulated (primary) cell (red) and neighboring (secondary) responders (black). Red dashed lines show time points in top panel. Inset shows experiment performed in presence of P2 receptor antagonist suramin (100 μM). (B) Correlation between the primary response amplitude and area under curve of secondary [Ca²⁺]_i elevations is shown for C2-OBs (left) and CB-OBs (right). (C and D) Correlation between distance from primary cell and observed response probability P_O of neighboring cells (C) and observed response time T_O after mechanical stimulation (D) is shown for C2-OBs (left) and CB-OBs (right). Black dashed lines show linear regressions. (E) Receiver operating characteristic curves demonstrate the performance of the logistic regression model in predicting incidence of secondary responses based on primary response parameters (blue), primary response parameters and distance (dist., red), or chance alone (gray) for C2-OBs (left) and CB-OBs (right). Accuracies of logistic models ± SEM are shown; N indicates number of trials. To see this figure in color, go online.