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. Author manuscript; available in PMC: 2018 Feb 20.
Published in final edited form as: Neuroscience. 2016 Dec 22;343:384–397. doi: 10.1016/j.neuroscience.2016.12.021

Figure 2.

Figure 2

Changes in the number of hippocampal spine synapses in response to inescapable stress during the simulated postpartum period in untreated controls (panel Veh), hormone-withdrawn ‘postpartum’ females (panel PpD), simulated proestrus animals (panel ProE), and hormone-treated ‘postpartum’ rats (panel Horm). Three distinct hippocampal areas were analyzed, CA1 stratum radiatum (CA1sr), CA3 stratum lucidum/radiatum (CA3sl/sr), and dentate gyrus stratum moleculare (DGsm). Synapses were counted using unbiased electron microscopic stereology. Diagram columns represent the estimated number of all spine synapses within a particular hippocampal area. Three-way mixed ANOVA (stress × hormone treatment × area) found a significant main stress effect and also revealed a significant hormone treatment × stress interaction effect, indicating that hormone treatment interferes with the ability of stress to modulate hippocampal spine synapse numbers (stress effect, F1,16=635.357 P<0.001; hormone treatment × stress interaction, F3,16=109.665 P<0.001).

Relative to sham-stressed untreated controls (Panel Veh, NS), hormone treatment of nonstressed (NS) females increased the number of spine synapses across all hippocampal areas in simulated proestrus animals and reduced synapse numbers in CA1sr of hormone-treated ‘postpartum’ rats (panel ProE, #P<0.02; panel Horm, #P<0.02; Tukey-Kramer test). When compared with respective sham-stressed (NS) rats, inescapable stress (IS) decreased synapse numbers across all hippocampal areas in untreated controls, hormone-withdrawn ‘postpartum’ females, and simulated proestrus animals, but not in hormone-treated ‘postpartum’ rats (panel Veh, *P<0.04; panel PpD, *P<0.01; panel ProE, *P<0.01; panel Horm, P>0.2; Tukey-Kramer test). With respect to stressed untreated controls (Panel Veh, IS), synapse numbers of stressed (IS) females remained higher in CA3sl/sr of simulated proestrus animals, as well as in CA3sl/sr and DGsm of hormone-treated ‘postpartum’ rats (panel ProE, +P<0.001; panel Horm, +P<0.01; Tukey-Kramer test).