Facilitation of AMPA Receptor Synaptic Delivery as a Molecular Mechanism for Cognitive Enhancement
(A) Fluorescence image of CA1 pyramidal neuron injected with Lucifer Yellow (green). DAPI nuclear staining (blue) was used to facilitate intracellular injection into the soma. Bar = 50 µm. (B) Confocal projection image of CA1 pyramidal neurons (left) and the same neuron processed for DAB staining (right). Bar = 20 µm. (C) High-magnification images of representative spiny dendrites. Bar = 10 µm. (D) Quantification of spine density from stratum radiatum CA1 dendrites. N, number of animals. (E) Quantification of spine density sorted by branch order (1–4) of the oblique apical dendrite. (F) Maximum-projection confocal images of a basal CA1 dendritic segment before (left) and after (right) the blind deconvolution protocol (10 iterations). Bar = 1 µm. (G) Maximum-projection image of a dendrite after blind deconvolution (left) and the same dendritic segment with marked spine heads (red) as used to measure head volumes (right). Bar = 2 µm. (H) Higher magnification of a short dendritic segment that shows the measurements of each spine (i.e., spine head volume and neck length). Bar = 0.5 µm. (I) Quantification of spine head volume in FGL and control rats. N, number of animals. (J) Cumulative frequency of spine head volume from the same data as in (I). N, number of spines. (K) Electron micrographs that show a representative neuropil in the stratum radiatum. Symmetric and asymmetric synapses were identified to quantify synaptic density using unbiased stereology. Bar = 0.5 µm. (L) Quantification of synaptic density in FGL and control rats. N, the number of animals. (M) Cumulative frequency of postsynaptic density length. N, number of synaptic profiles.