Ovarian steroids increase PSD-95 expression and dendritic spines in the dorsal raphe of ovariectomized macaques
Article first published online: 12 SEP 2013
Copyright © 2013 Wiley Periodicals, Inc.
Volume 67, Issue 12, pages 897–908, December 2013
How to Cite
Rivera, H. M. and Bethea, C. L. (2013), Ovarian steroids increase PSD-95 expression and dendritic spines in the dorsal raphe of ovariectomized macaques. Synapse, 67: 897–908. doi: 10.1002/syn.21702
- Issue published online: 15 OCT 2013
- Article first published online: 12 SEP 2013
- Accepted manuscript online: 20 AUG 2013 04:04AM EST
- Manuscript Accepted: 10 AUG 2013
- Manuscript Revised: 30 JUL 2013
- Manuscript Received: 26 FEB 2013
- NIH. Grant Numbers: MH062677, T32HD007133
- N.L. Tartar Research Fund. Grant Numbers: P30-NS061800, P51 OD011092
- dendritic spines;
Estradiol (E) and progesterone (P) promote spinogenesis in several brain areas. Intracellular signaling cascades that promote spinogenesis involve RhoGTPases, glutamate signaling and synapse assembly. We found that in serotonin neurons, E ± P administration increases (a) gene and protein expression of RhoGTPases, (b) gene expression of glutamate receptors, and (c) gene expression of pivotal synapse assembly proteins. Therefore, in this study we determined whether structural changes in dendritic spines in the dorsal raphe follow the observed changes in gene and protein expression. Dendritic spines were examined with immunogold silver staining of a spine marker protein, postsynaptic density-95 (PSD-95) and with Golgi staining. In the PSD-95 study, adult Ovx monkeys received placebo, E, P, or E + P for 1 month (n = 3/group). Sections were immunostained for PSD-95 and the number of PSD-95-positive puncta was determined with stereology. E, P, and E + P treatment significantly increased the total number of PSD-95-positive puncta (ANOVA, P = 0.04). In the golgi study, adult Ovx monkeys received placebo, E or E + P for 1 month (n = 3–4) and the midbrain was golgi-stained. A total of 80 neurons were analyzed with Neurolucida software. There was a significant difference in spine density that depended on branch order (two-way ANOVA). E + P treatment significantly increased spine density in higher-order (3°–5°) dendritic branches relative to Ovx group (Bonferroni, P < 0.05). In summary, E + P leads to the elaboration of dendritic spines on dorsal raphe neurons. The ability of E to induce PSD-95, but not actual spines, suggests either a sampling or time lag issue. Increased spinogenesis on serotonin dendrites would facilitate excitatory glutamatergic input and, in turn, increase serotonin neurotransmission throughout the brain. Synapse 67:897–908, 2013. © 2013 Wiley Periodicals, Inc.