Fig. 3. Effect of local anesthetic (LA) on neuronal Ca2+cyt: Quantitative analysis of average neuronal Ca2+cytduring 0–10 min exposure to LA. Bupivacaine is plotted as its equipotent lidocaine concentration to facilitate comparisons between LAs;e.g. , bupivacaine graphed on the x-axis as 1.0% is actually 0.25% bupivacaine. Tris controls are plotted as the LA concentration to which they are equimolar, and for which they serve as a specific control. Note the log–log plot to accommodate the wide range of average Ca2+cytvalues. Inset displays nonlogarithmic plot of same data for LA equipotent to 0.1–1.0% lidocaine, to illustrate increase of Ca2+cytwith LA concentration during the 0–10 min period. Symbols used to indicate statistical significance: L =P < 0.001 lidocaine versus equimolar Tris (same concentration and time); B =P < 0.001 bupivacaine versus equimolar Tris (same concentration and time); ##=P < 0.001 lidocaine versus bupivacaine (same concentration and time); #=P < 0.05 lidocaine versus bupivacaine (same concentration and time); **=P < 0.001 concentration effect for single LA (linear regression of all concentrations tested).