Fig. 1.

Basal hippocampal CA1 dendrites progressively regress with repeated CORT exposure. (a) Experimental timeline indicating CORT exposure and sample collection time points. (b) Camera lucida renderings of representative neurons. (c) Prolonged CORT exposure induced durable dendrite arbor regression, with atrophy on distal branches emerging as early as 11 days of exposure, then progressing to more proximal branches with more prolonged exposure. Inset: 11 days of exposure reduced branch intersections on distal dendrites (rings 5–7) in a manner that was indistinguishable from atrophy caused by longer exposure periods [main effect F_(4,105) = 4.6, p = 0.002]. (d) Prolonged CORT exposure did not impact the complexity of apical trees of hippocampal CA1 neurons. (e) Overall basal dendrite lengths were reduced with 21 days of CORT exposure, and this did not recover. (f) Overall apical dendrite length did not change. (g) Basal dendrite branch points were also reduced with 21 days of CORT exposure, and counts did not recover. (h) Apical branch points were elevated after 11 days of CORT exposure and also with 21 days of recovery following a 21-day exposure period. Means + SEMs, *p < 0.05 vs. control; **p < 0.05 control vs. CORT + washout groups, ^p < 0.1 control vs. CORT + washout groups. n = 17–23 neurons/group; 8–12 mice/group.