TABLE 1.
BDNF-Induced Dendritic Ca2+ Signals in CA1 Pyramidal Neurons
| ACSF Composition | Baseline Pre-BDNF 360/380 Ratio |
Initial Signal (Before IBDNF) (100 s From BDNF Puff) 360/380 Ratio |
Sustained Signal (at IBDNF Peak) (440 s From BDNF Puff) 360/380 Ratio |
|---|---|---|---|
| TTX (n = 7) | 0.89 ± 0.03 (0.08) | 1.26 ± 0.14 (0.19) | 1.71 ± 0.09 (0.14) |
| TTX, APV, Cd2+ (n = 4) | 1.15 ± 0.11 (0.18) | 1.31 ± 0.26 (0.28) | 2.12 ± 0.35 (0.33) |
| Pooled data (n = 11) | 0.98 ± 0.05 (0.18) | 1.28 ± 0.11 (0.2) | 1.86 ± 0.14 (0.25) |
Maximum values (means ± SE) of brain-derived neurotrophic factor (BDNF)-induced Ca2+ elevations in voltage-clamped CA1 pyramidal neurons in the absence of action potential firing (TTX). Blocking N-methyl-d-aspartate receptors (NMDARs; APV) and voltage-gated Ca2+ channels (Cd2+) yielded similar responses. Initial Ca2+ signals always occurred in the targeted dendritic locations, whereas the sustained signals were widespread throughout the somato-dendritic compartment. Background-subtracted fluorescence intensity measurements were obtained within regions of interest (ROIs) defined over apical primary and secondary dendrites as well as somata. The average ratio of 360 and 380 nm fluorescence within each ROI was used as an estimate of intracellular Ca2+ concentration as these two parameters are directly proportional to each other (see methods for more details). The coefficient of variance (in parentheses, CV = SD/mean) is provided as a measure of consistency.