Figure 3.

Spiny PVIs and Spiny Segments of PVIs Lack PNNs

(A) Confocal image stack showing immunoreactivity for GFP (green) and PV (blue) as well as vicia villosa lectin staining for PNNs (red) for one spiny (arrow) and one non-spiny (arrowhead) PVI.

(B) Left, magnifications of the boxed dendrites of the spiny (i) and the non-spiny (ii) PVI in the merged image in (A). Right, corresponding gray scale conversions of the GFP channel. Arrowheads indicate examples of spines. Note that PNNs strongly ensheathe soma and dendrites of the non-spiny neuron but not the spiny neuron.

(C and D) Differences in PNN wrapping of somata (C) and dendrites (D) were quantified by calculating the individual volume ratios of the surrounding PNN and the respective soma or dendrite (n = 45 neurons, 5 mice).

(E) Example image showing that spiny and non-spiny dendritic segments of the same neuron are differentially enwrapped by PNNs (arrows). Bars are means ± SEM.