Effects of blockers of receptors on changes by CORT in the density and morphology of spines.

<p>(A) Effects of treatments by 1 µM CORT and blockers of receptors on the total spine density in CA1 neurons. A 1 h treatment in ACSF without drugs (Control), with 1 µM CORT (CORT), with 1 µM and 10 µM RU486 (CORT + RU), with 1 µM CORT and 50 µM MK-801 (CORT + MK), with 1 µM CORT and 20 µM CNQX (CORT + CNQX). (B) Histogram of spine head diameters after a 1 h treatment in ACSF without drugs (Control, open circle), with 1 µM CORT (CORT, closed black circle), and with 1 µM CORT and 10 µM RU486 (CORT + RU, closed red circle), with 1 µM CORT and 50 µM MK-801 (CORT + MK, closed blue circle), with 1 µM CORT and 20 µM CNQX (CORT + CNQX, closed green circle). Small-head spines (small), middle-head spines (middle), and large-head spines (large) are categorized. (C) Density of three subtypes of spines. Abbreviations are same as in (B). ACSF without drugs (open column), CORT (black column), CORT + RU (red column), CORT + MK (blue column), and CORT + CNQX (green column) are shown. (D) No effect of receptor inhibitors alone on the total spine density in CA1 neurons. Abbreviations are the same as in (A). Vertical axis is the average number of spines per 1 µm of dendrite. In (A) and (C), results are reported as mean ± SEM. In (A) and (C), the significance of CORT or drug effect was examined using the Tukey–Kramer <i>post hoc</i> multiple comparisons test when one way ANOVA tests yielded <i>P</i><0.05. *<i>P</i><0.05, **<i>P</i><0.01. For each drug treatment, we investigated 3 rats, 7 slices, 14 neurons, 28 dendrites and 1400–2000 spines, except for CORT which consists of 10 rats, 28 slices, 56 neurons, 113 dendrites and approx. 8000 spines. For control, we used 5 rats, 8 slices, 16 neurons, 31 dendrites and approx. 1700 spines.