Estrogen Increases Spine Density in Ventromedial Hypothalamic Neurons of Peripubertal Rats

Segarra, Annabell C.; McEwen, Bruce S.

doi:10.1159/000125915

Cited by 48 publications

(23 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dendrite specificity of estrogen-induced spines in the VMH may not have been detected in previous studies that analyzed only a single primary dendrite, specifically, the primary dendrite with the "greatest number of spines" (Frankfurt et al, 1990) or the "second longest primary dendrite" (Segarra and McEwen, 1991). Because results of the former study are similar to those of the present study, it is possible that the sample consisted mainly of short dendrites.…”

Section: Discussionsupporting

confidence: 42%

Estrogen Selectively Regulates Spine Density within the Dendritic Arbor of Rat Ventromedial Hypothalamic Neurons

2000

View full text Add to dashboard Cite

Estrogen acts in the hypothalamic ventromedial nucleus (VMH) to promote female sexual behavior. One potential mechanism through which estrogen may facilitate this behavior is by reconfiguring synaptic connections within the VMH. Estrogen treatment increases the number of synapses and dendritic spines in the VMH, but how this remodeling occurs within the context of the local, behaviorally relevant microcircuitry is unknown. The goal of this study was to localize estrogen-induced changes in spine density within the VMH and relate these to dendritic morphology and the presence of nuclear estrogen receptor. The hypothalami from ovariectomized rats, treated with either vehicle or estradiol, were lightly fixed, and VMH neurons were iontophoretically filled with Lucifer yellow. Confocal microscopy was used to examine neuronal morphology. Estrogen treatment increased dendritic spine density by 48% in the ventrolateral VMH but had no effect on spine density in the dorsal VMH. The primary dendrites of VMH neurons were differentially affected by estrogen. Estrogen treatment increased spine density twofold on the short primary dendrites but did not affect spine density on long primary dendrites. Immunocytochemical staining showed that none of the filled neurons expressed estrogen receptor-␣. Thus, although the effect of estrogen on spine density is localized to a VMH subdivision where estrogen receptor is expressed, estrogen treatment induces spines on neurons that lack estrogen receptor. Taken together, our results suggest that the effect of estrogen on ventrolateral VMH spines is selective within the dendritic arbor of a neuron and may be mediated by an indirect, possibly transynaptic, mechanism.

show abstract

Section: Discussionsupporting

confidence: 42%

Estrogen Selectively Regulates Spine Density within the Dendritic Arbor of Rat Ventromedial Hypothalamic Neurons

2000

View full text Add to dashboard Cite

show abstract

“…Repeated cocaine administration induces longterm adaptations within mesocorticolimbic circuits, such as changes in c-fos expression (Hiroi et al, 1997;Canales and Graybiel, 2000;Todtenkopf et al, 2002) and dendritic spine density (Robinson and Kolb, 1999) that consequently affect synaptic transmission (Thomas et al, 2001;Beurrier and Malenka, 2002). These changes have also been reported in the female after estrogen administration (Segarra and McEwen, 1991;Woolley et al, 1997;Priest and Roberts, 2000).…”

Section: Discussionmentioning

confidence: 95%

“…One important action of estrogen in the hippocampus of females is to promote neuronal growth and remodeling, as observed by spine formation and dendritic sprouting (Kadish and Van Groen, 2002;Sakamoto et al, 2003;Li et al, 2004;Tang et al, 2004). Thus, cocaine-induced changes in synaptic plasticity observed in mesolimbic neurons of males (Kolb et al, 2003) could possibly be facilitated by the presence of estrogen in females (Segarra and McEwen, 1991). Additional studies will be needed to confirm this possibility.…”

Section: Discussionmentioning

confidence: 99%

Estrogen Influences Cocaine-Induced Blood Oxygen Level-Dependent Signal Changes in Female Rats

Febo¹,

Ferris²,

Segarra³

2005

J. Neurosci.

View full text Add to dashboard Cite

We investigated the effect of estrogen on cocaine-induced brain activity using blood oxygen level-dependent (BOLD) magnetic resonance imaging. Ovariectomized (Ovx) rats without estrogen and Ovx rats with estrogen (OvxϩE) were given a single saline or cocaine injection (15 mg/kg, i.p.) for 5 d. After 7 d of withdrawal from injections, rats were challenged with cocaine during functional imaging. Acute cocaine administration produced positive BOLD activation in the prefrontal cortex, nucleus accumbens, striatum, ventral tegmental area, and hippocampus, among other brain regions. Positive BOLD signal changes were lower in OvxϩE than in Ovx rats. With repeated cocaine administration, OvxϩE rats showed enhanced BOLD signal changes in the nucleus accumbens, ventral tegmental area, and hippocampus compared with acutely treated animals. Our results indicate that estrogen influences the effects of acute and repeated cocaine administration on BOLD signal changes. The data suggest that in females with estrogen, cocaine-induced neuronal activity is enhanced after repeated cocaine administration. It is possible that the actions of estrogen within the aforementioned brain regions potentiate the behavioral response to cocaine observed in female rats.

show abstract

“…Thus, during puberty, there can be estrogendependent as well as estrogen-independent developmental changes in brain circuitry (Romeo, 2003). Evidence for the estrogen-dependence of this process is shown in the developing hypothalamus, in which the increases in indicators of brain plasticity are accelerated by administration of exogenous estradiol to prepubertal female rats (Segarra & McEwen, 1991;Clough & Rodriguez-Sierra, 1983). Similarly, in ventromedial hypothalamus, estradiol treatment to ovariectomized rats increases dendritic plasticity Carrer & Agustin, 1982).…”

Section: Hippocampal Plasticity and Pubertymentioning

confidence: 99%

Postpubertal decrease in hippocampal dendritic spines of female rats

Yıldırım

Mapp

Janssen

et al. 2008

Experimental Neurology

View full text Add to dashboard Cite

Hippocampal dendritic spine and synapse numbers in female rats vary across the estrous cycle and following experimental manipulation of hormone levels in adulthood. Based on behavioral studies demonstrating that learning patterns are altered following puberty, we hypothesized that dendritic spine number in rat hippocampal CA1 region would change post-pubertally. Female SpragueDawley rats were divided into prepubertal (postnatal day (P) 22), peripubertal (P35) and postpubertal (P49) groups, with the progression of puberty evaluated by vaginal opening, and estrous cyclicity subsequently assessed by daily vaginal smears. Spinophilin immunoreactivity in dendritic spines was used as an index of spinogenesis in area CA1 stratum radiatum (CA1sr) of hippocampus. First, electron microscopy analyses confirmed the presence of spinophilin specifically in dendritic spines of CA1sr, supporting spinophilin as a reliable marker of hippocampal spines in young female rats. Second, stereologic analysis was performed to assess the total number of spinophilin-immunoreactive puncta (i.e. spines) and CA1sr volume in developing rats. Our results indicated that the number of spinophilin-immunoreactive spines in CA1sr was decreased 46% in the post-pubertal group compared to the two younger groups, whereas the volume of the hippocampus underwent an overall increase during this same developmental time frame. Third, to determine a potential role of estradiol in this process, an additional group of rats was ovariectomized (OVX) prepubertally at P22, then treated with estradiol or vehicle at P35, and spinophilin quantified as above in rats perfused on P49. No difference in spinophilin puncta number was found in OVX rats between the two hormone groups, suggesting that this developmental decrease is independent of peripheral estradiol. These changes in spine density coincident with puberty may be related to altered hippocampal plasticity and synaptic consolidation at this phase of maturity.

show abstract

Estrogen Increases Spine Density in Ventromedial Hypothalamic Neurons of Peripubertal Rats

Cited by 48 publications

References 26 publications

Estrogen Selectively Regulates Spine Density within the Dendritic Arbor of Rat Ventromedial Hypothalamic Neurons

Estrogen Selectively Regulates Spine Density within the Dendritic Arbor of Rat Ventromedial Hypothalamic Neurons

Estrogen Influences Cocaine-Induced Blood Oxygen Level-Dependent Signal Changes in Female Rats

Postpubertal decrease in hippocampal dendritic spines of female rats

Contact Info

Product

Resources

About