Figure 6.

Calcium dependence in activity-induced fusion of BDNF–pHluorin vesicles. A, B, Average changes of BDNF–pHluorin puncta fluorescence changes induced by field stimulation (40 pulses, 10 Hz) at different [Ca²⁺]_o at axons (±SEM; n = 215 puncta in 9 axons) and dendrites (n = 231 puncta in 8 dendrites). Insets, Average peak fluorescence change, normalized to that observed at 2 mm [Ca²⁺]_o. C, Average changes of BDNF–pHluorin puncta fluorescence recorded from a single axon and dendrite, in the presence of various concentrations of Cd²⁺ in the culture medium. Bar graphs, Average peak fluorescence change, normalized to that at 0 mm [Cd²⁺]_o. D, E, Average changes of peak BDNF–pHluorin puncta fluorescence at axons and dendrites induced by either field stimulation of the culture or loose-patch stimulation of individual soma, in the presence of various blockers of glutamate receptors and L-type Ca²⁺ channels, and normalized by those observed in the absence of drug treatment (n = 3–7 neurons for each group). Nim, Nimodipine.