Fig. 6.

Effects of Ca²⁺-free medium on the KCl-induced increase in dendritic localization of BDNF and TrkB mRNAs. Quantitative analysis of the MDDL for BDNF and TrkB mRNAs in nominally Ca²⁺-free medium supplemented with 10 μm EGTA or BAPTA-AM. Bars indicate the fold increase, with respect to controls, of the mean maximal distance at which the in situ labeling was detectable (MDDL) for 80–150 dendrites. A, In nominally Ca²⁺-free medium the MDDL for BDNF mRNA, induced by depolarization with 10 mm KCl for 3 hr, does not change with respect to controls. The effects are identical in the presence of either EGTA or BAPTA-AM. B, MDDL for TrkB mRNA. At the level of p ≤ 0.05 (Student’st test), no significant variation in MDDL with respect to controls can be observed when cultures are depolarized under Ca²⁺-free conditions. Identical effects are seen with either EGTA or BAPTA-AM. C, Unstimulated controls in normal medium. CEGTA, Unstimulated controls maintained 3 hr in Ca²⁺-free medium containing EGTA;CBAPTA-AM, unstimulated controls maintained 3 hr in Ca²⁺-free medium containing BAPTA-AM; 3h K EGTA, neurons stimulated with 10 mm KCl in Ca²⁺-free medium containing EGTA; 3h K BAPTA-AM, neurons stimulated with 10 mm KCl in Ca²⁺-free medium containing BAPTA-AM. Error bars represent SE.