Fig. 2.

Intensity dependence of BS-induced BDNF release (A). BS was applied at intensities and durations ranging from A-fiber (0.1–1 mA, 0.1 msec) to C-fiber (5–10 mA, 0.5 msec) strength. Numbers inside columnsindicate the number of slices. *p < 0.05 versus basal values (B) (ANOVA, followed by Dunnett's test). B, Calcium dependence of BS-induced BDNF release. BS induced the release of BDNF-LI in the presence of Ca²⁺ ions (▴) but not when slices were superfused with Ca²⁺-free Krebs' solution containing 10 mm EDTA (▪). BS (300 stimuli; 10 mA, 0.5 msec, 100 Hz) was applied (arrow) after collection of two basal outflow fractions. Points represent means ± SE of four slices. *p < 0.05 versus analog fractions collected in the presence of Ca²⁺ (ANOVA, followed by Tukey's test). C, TTX superfusion blocked BS-induced BDNF release without changing basal outflow. TTX (2 μm) was superfused during the last 2 min of the third fraction (basal) and the first minute of the fourth fraction (stimulated) (■;n = 4 slices). Four slices were run in the absence of TTX as controls (▴). BS (300 stimuli; 10 mA, 0.5 msec, 100 Hz) was applied (arrow) after collection of three basal outflow fractions. Points represent means ± SEM. *p < 0.05 versus analog fractions collected in the presence of TTX (ANOVA, followed by Tukey's test).