151
|
Zhang Y, Xiao X, Zhang XM, Zhao ZQ, Zhang YQ. Estrogen facilitates spinal cord synaptic transmission via membrane-bound estrogen receptors: implications for pain hypersensitivity. J Biol Chem 2012; 287:33268-81. [PMID: 22869379 DOI: 10.1074/jbc.m112.368142] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Recent evidence suggests that estrogen is synthesized in the spinal dorsal horn and plays a role in nociceptive processes. However, the cellular and molecular mechanisms underlying these effects remain unclear. Using electrophysiological, biochemical, and morphological techniques, we here demonstrate that 17β-estradiol (E2), a major form of estrogen, can directly modulate spinal cord synaptic transmission by 1) enhancing NMDA receptor-mediated synaptic transmission in dorsal horn neurons, 2) increasing glutamate release from primary afferent terminals, 3) increasing dendritic spine density in cultured spinal cord dorsal horn neurons, and 4) potentiating spinal cord long term potentiation (LTP) evoked by high frequency stimulation (HFS) of Lissauer's tract. Notably, E2-BSA, a ligand that acts only on membrane estrogen receptors, can mimic E2-induced facilitation of HFS-LTP, suggesting a nongenomic action of this neurosteroid. Consistently, cell surface biotinylation demonstrated that three types of ERs (ERα, ERβ, and GPER1) are localized on the plasma membrane of dorsal horn neurons. Furthermore, the ERα and ERβ antagonist ICI 182,780 completely abrogates the E2-induced facilitation of LTP. ERβ (but not ERα) activation can recapitulate E2-induced persistent increases in synaptic transmission (NMDA-dependent) and dendritic spine density, indicating a critical role of ERβ in spinal synaptic plasticity. E2 also increases the phosphorylation of ERK, PKA, and NR2B, and spinal HFS-LTP is prevented by blockade of PKA, ERK, or NR2B activation. Finally, HFS increases E2 release in spinal cord slices, which can be prevented by aromatase inhibitor androstatrienedione, suggesting activity-dependent local synthesis and release of endogenous E2.
Collapse
Affiliation(s)
- Yan Zhang
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | | | | | | | | |
Collapse
|
152
|
Ooishi Y, Kawato S, Hojo Y, Hatanaka Y, Higo S, Murakami G, Komatsuzaki Y, Ogiue-Ikeda M, Kimoto T, Mukai H. Modulation of synaptic plasticity in the hippocampus by hippocampus-derived estrogen and androgen. J Steroid Biochem Mol Biol 2012; 131:37-51. [PMID: 22075082 DOI: 10.1016/j.jsbmb.2011.10.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 09/27/2011] [Accepted: 10/12/2011] [Indexed: 12/29/2022]
Abstract
The hippocampus synthesizes estrogen and androgen in addition to the circulating sex steroids. Synaptic modulation by hippocampus-derived estrogen or androgen is essential to maintain healthy memory processes. Rapid actions (1-2h) of 17β-estradiol (17β-E2) occur via synapse-localized receptors (ERα or ERβ), while slow genomic E2 actions (6-48h) occur via classical nuclear receptors (ERα or ERβ). The long-term potentiation (LTP), induced by strong tetanus or theta-burst stimulation, is not further enhanced by E2 perfusion in adult rats. Interestingly, E2 perfusion can rescue corticosterone (stress hormone)-induced suppression of LTP. The long-term depression is modulated rapidly by E2 perfusion. Elevation of the E2 concentration changes rapidly the density and head structure of spines in neurons. ERα, but not ERβ, drives this enhancement of spinogenesis. Kinase networks are involved downstream of ERα. Testosterone (T) or dihydrotestosterone (DHT) also rapidly modulates spinogenesis. Newly developed Spiso-3D mathematical analysis is used to distinguish these complex effects by sex steroids and kinases. It has been doubted that the level of hippocampus-derived estrogen and androgen may not be high enough to modulate synaptic plasticity. Determination of the accurate concentration of E2, T or DHT in the hippocampus is enabled by mass-spectrometric analysis in combination with new steroid-derivatization methods. The E2 level in the hippocampus is approximately 8nM for the male and 0.5-2nM for the female, which is much higher than that in circulation. The level of T and DHT is also higher than that in circulation. Taken together, hippocampus-derived E2, T, and DHT play a major role in modulation of synaptic plasticity.
Collapse
Affiliation(s)
- Yuuki Ooishi
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
153
|
Ziehn MO, Avedisian AA, Dervin SM, O’Dell TJ, Voskuhl RR. Estriol preserves synaptic transmission in the hippocampus during autoimmune demyelinating disease. J Transl Med 2012; 92:1234-45. [PMID: 22525427 PMCID: PMC4343001 DOI: 10.1038/labinvest.2012.76] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Cognitive deficits occur in over half of multiple sclerosis patients, with hippocampal-dependent learning and memory commonly impaired. Data from in vivo MRI and post-mortem studies in MS indicate that the hippocampus is targeted. However, the relationship between structural pathology and dysfunction of the hippocampus in MS remains unclear. Hippocampal neuropathology also occurs in experimental autoimmune encephalomyelitis (EAE), the most commonly used animal model of MS. Although estrogen treatment of EAE has been shown to be anti-inflammatory and neuroprotective in the spinal cord, it is unknown if estrogen treatment may prevent hippocampal pathology and dysfunction. In the current study we examined excitatory synaptic transmission during EAE and focused on pathological changes in synaptic protein complexes known to orchestrate functional synaptic transmission in the hippocampus. We then determined if estriol, a candidate hormone treatment, was capable of preventing functional changes in synaptic transmission and corresponding hippocampal synaptic pathology. Electrophysiological studies revealed altered excitatory synaptic transmission and paired-pulse facilitation (PPF) during EAE. Neuropathological experiments demonstrated that there were decreased levels of pre- and post-synaptic proteins in the hippocampus, diffuse loss of myelin staining and atrophy of the pyramidal layers of hippocampal cornu ammonis 1 (CA1). Estriol treatment prevented decreases in excitatory synaptic transmission and lessened the effect of EAE on PPF. In addition, estriol treatment prevented several neuropathological alterations that occurred in the hippocampus during EAE. Cross-modality correlations revealed that deficits in excitatory synaptic transmission were significantly correlated with reductions in trans-synaptic protein binding partners known to modulate excitatory synaptic transmission. To our knowledge, this is the first report describing a functional correlate to hippocampal neuropathology in any MS model. Furthermore, a treatment was identified that prevented both deficits in synaptic function and hippocampal neuropathology.
Collapse
Affiliation(s)
- Marina O. Ziehn
- Interdepartmental Program of Neuroscience, University of California, Los Angeles
- Multiple Sclerosis Program, Department of Neurology, University of California, Los Angeles
| | - Andrea A. Avedisian
- Multiple Sclerosis Program, Department of Neurology, University of California, Los Angeles
| | - Shannon M. Dervin
- Multiple Sclerosis Program, Department of Neurology, University of California, Los Angeles
| | - Thomas J. O’Dell
- Department of Physiology, David Geffen School of Medicine at the University of California, Los Angeles
| | - Rhonda R. Voskuhl
- Multiple Sclerosis Program, Department of Neurology, University of California, Los Angeles
| |
Collapse
|
154
|
Ji Y, Tang B, Cao DY, Wang G, Traub RJ. Sex differences in spinal processing of transient and inflammatory colorectal stimuli in the rat. Pain 2012; 153:1965-1973. [PMID: 22819535 DOI: 10.1016/j.pain.2012.06.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 06/14/2012] [Accepted: 06/19/2012] [Indexed: 02/06/2023]
Abstract
Sex differences in the spinal processing of somatic and visceral stimuli contribute to greater female sensitivity in many pain disorders. The present study examined spinal mechanisms that contribute to sex differences in visceral sensitivity. The visceromotor response to colorectal distention (CRD) was more robust in normal female rats and after intracolonic mustard oil compared with that in male rats. No sex difference was observed in the CRD-evoked response of lumbosacral (LS) and thoracolumbar (TL) colonic afferents in normal and mustard oil-treated rats, but there was a sex difference in spontaneous activity that was exacerbated by intracolonic mustard oil. The response of visceroceptive dorsal horn neurons to CRD was greater in normal female rats in the LS and TL spinal segments. The effect of intracolonic mustard oil on the CRD-evoked response of different phenotypes of visceroceptive dorsal horn neurons was dependent on sex and segment. The NMDA receptor antagonist 2-amino-5-phosphonopentanoic acid (APV) dose-dependently attenuated the visceromotor response in normal rats with greater effect in male rats. Correspondingly, there was greater cell membrane expression of the GluN1 subunit in dorsal horn extracts in female rats. After intracolonic mustard oil, there was no longer a sex difference in the effect of APV nor GluN1 expression in LS segments, but greater female expression in TL segments. These data document a sex difference in spinal processing of nociceptive visceral stimuli from the normal and inflamed colon. Differences in dorsal horn neuronal activity and NMDA receptor expression contribute to the sex differences in the visceral sensitivity observed in awake rats.
Collapse
Affiliation(s)
- Yaping Ji
- Department of Neural and Pain Sciences, School of Dentistry, University of Maryland, Baltimore, MD, USA Center for Pain Studies, University of Maryland, Baltimore, MD, USA Program in Neuroscience, University of Maryland, Baltimore, MD, USA
| | | | | | | | | |
Collapse
|
155
|
Frick KM. Building a better hormone therapy? How understanding the rapid effects of sex steroid hormones could lead to new therapeutics for age-related memory decline. Behav Neurosci 2012; 126:29-53. [PMID: 22289043 DOI: 10.1037/a0026660] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A wealth of data collected in recent decades has demonstrated that ovarian sex-steroid hormones, particularly 17β-estradiol (E2), are important trophic factors that regulate the function of cognitive regions of the brain such as the hippocampus. The loss of hormone cycling at menopause is associated with cognitive decline and dementia in women, and the onset of memory decline in animal models. However, hormone therapy is not currently recommended to prevent or treat cognitive decline, in part because of its detrimental side effects. In this article, it is proposed that investigations of the rapid effects of E2 on hippocampal function be used to further the design of new drugs that mimic the beneficial effects of E2 on memory without the side effects of current therapies. A conceptual model is presented for elucidating the molecular and biochemical mechanisms through which sex-steroid hormones modulate memory, and a specific hypothesis is proposed to account for the rapid memory-enhancing effects of E2. Empirical support for this hypothesis is discussed as a means of stimulating the consideration of new directions for the development of hormone-based therapies to preserve memory function in menopausal women.
Collapse
Affiliation(s)
- Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, 2441 East Hartford Avenue, Milwaukee, WI 53211, USA.
| |
Collapse
|
156
|
Stelly CE, Cronin J, Daniel JM, Schrader LA. Long-term oestradiol treatment enhances hippocampal synaptic plasticity that is dependent on muscarinic acetylcholine receptors in ovariectomised female rats. J Neuroendocrinol 2012; 24:887-96. [PMID: 22313316 DOI: 10.1111/j.1365-2826.2012.02287.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Short-term oestradiol treatment modulates hippocampus-dependent memory and synaptic plasticity in the hippocampus. Long-term oestradiol treatment can also enhance hippocampus- dependent memory, although the effects of long-term oestradiol treatment on synaptic plasticity are unknown. We investigated the effects of long-term oestradiol treatment on synaptic plasticity at the Schaeffer Collateral/CA1 synapse in 8-month-old female rats. In addition, we determined the role of endogenous activation of muscarinic acetylcholine receptors (mAChRs) in synaptic transmission and plasticity using scopolamine (1 μm), an antagonist of mAChRs. Hippocampus slices from ovariectomised rats that were treated with oestradiol-containing capsules for 5 months were compared with slices from ovariectomised rats that received cholesterol-containing capsules. Unexpectedly, scopolamine application significantly increased the baseline field excitatory postsynaptic potentials (fEPSP) and decreased paired pulse facilitation (PPF) in slices from cholesterol-treated rats. Baseline fEPSPs and PPF were not significantly modulated in slices from oestradiol-treated rats by scopolamine. Slices from oestradiol-treated rats showed enhanced long-term potentiation relative to slices from cholesterol-treated rats. Scopolamine significantly reduced the magnitude of plasticity in slices from oestradiol-treated rats. Taken together, these results suggest that mAChRs have a significant effect on baseline synaptic transmission through a decrease in the probability of glutamate release in slices from cholesterol-treated rats. Long-term oestradiol treatment blocks this effect and enhances theta-burst stimulation-induced synaptic plasticity in the middle-aged female rat, and this effect is mediated by activation of mAChRs.
Collapse
Affiliation(s)
- C E Stelly
- Neuroscience Program, Tulane University, New Orleans, LA, USA
| | | | | | | |
Collapse
|
157
|
G-protein-coupled receptor 30 mediates rapid neuroprotective effects of estrogen via depression of NR2B-containing NMDA receptors. J Neurosci 2012; 32:4887-900. [PMID: 22492045 DOI: 10.1523/jneurosci.5828-11.2012] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
17-β-estradiol (E2) is a steroid hormone involved in neuroprotection against excitotoxicity and other forms of brain injury. Through genomic and nongenomic mechanisms, E2 modulates neuronal excitability and signal transmission by regulating NMDA and non-NMDA receptors. However, the mechanisms and identity of the receptors involved remain unclear, even though studies have suggested that estrogen G-protein-coupled receptor 30 (GPR30) is linked to protection against ischemic injury. In the culture cortical neurons, treatment with E2 and the GPR30 agonist G1 for 45 min attenuated the excitotoxicity induced by NMDA exposure. The acute neuroprotection mediated by GPR30 is dependent on G-protein-coupled signals and ERK1/2 activation, but independent on transcription or translation. Knockdown of GPR30 using short hairpin RNAs (shRNAs) significantly reduced the E2-induced rapid neuroprotection. Patch-clamp recordings revealed that GPR30 activation depressed exogenous NMDA-elicited currents. Short-term GPR30 activation did not affect the expression of either NR2A- or NR2B-containing NMDARs; however, it depressed NR2B subunit phosphorylation at Ser-1303 by inhibiting the dephosphorylation of death-associated protein kinase 1 (DAPK1). DAPK1 knockdown using shRNAs significantly blocked NR2B subunit phosphorylation at Ser-1303 and abolished the GPR30-mediated depression of exogenous NMDA-elicited currents. Lateral ventricle injection of the GPR30 agonist G1 (0.2 μg) provided significant neuroprotection in the ovariectomized female mice subjected to middle cerebral artery occlusion. These findings provide direct evidence that fast neuroprotection by estradiol is partially mediated by GPR30 and the subsequent downregulation of NR2B-containing NMDARs. The modulation of DAPK1 activity by GPR30 may be an important mediator of estradiol-dependent neuroprotection.
Collapse
|
158
|
Choleris E, Clipperton-Allen AE, Phan A, Valsecchi P, Kavaliers M. Estrogenic involvement in social learning, social recognition and pathogen avoidance. Front Neuroendocrinol 2012; 33:140-59. [PMID: 22369749 DOI: 10.1016/j.yfrne.2012.02.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 02/13/2012] [Accepted: 02/14/2012] [Indexed: 12/25/2022]
Abstract
Sociality comes with specific cognitive skills that allow the proper processing of information about others (social recognition), as well as of information originating from others (social learning). Because sociality and social interactions can also facilitate the spread of infection among individuals the ability to recognize and avoid pathogen threat is also essential. We review here various studies primarily from the rodent literature supporting estrogenic involvement in the regulation of social recognition, social learning (socially acquired food preferences and mate choice copying) and the recognition and avoidance of infected and potentially infected individuals. We consider both genomic and rapid estrogenic effects involving estrogen receptors α and β, and G-protein coupled estrogen receptor 1, along with their interactions with neuropeptide systems in the processing of social stimuli and the regulation and expression of these various socially relevant behaviors.
Collapse
Affiliation(s)
- Elena Choleris
- Department of Psychology, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
| | | | | | | | | |
Collapse
|
159
|
Palmeira CCDA, Ashmawi HA, Posso IDP. Sex and pain perception and analgesia. Rev Bras Anestesiol 2012; 61:814-28. [PMID: 22063383 DOI: 10.1016/s0034-7094(11)70091-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 02/21/2011] [Indexed: 10/26/2022] Open
Abstract
Sex is an important factor in painful experience modulation. Large volume of evidence shows that experience is different for males and females, as well as the answer to some classes of analgesics. Laboratory experiments suggest that women have a lower pain threshold than men related to pain from noxious stimuli such as heat, cold, pressure and electrical stimulation. Pain is a dynamic phenomenon under the influence of various mechanisms of excitatory and inhibitory control. The differences in pain perception related to sex may be associated with hyperalgesia in women, but also to the hypoactivity of the inhibitory system of pain in females. The purpose of this review besides showing some relationship for gonadal hormones, central nervous system and pain is to provide reference points for the discussion of one of the most intriguing aspects of the pathophysiology of pain: the differences in the presence of painful stimuli related to gender.
Collapse
|
160
|
Tanaka M, Sokabe M. Continuous de novo synthesis of neurosteroids is required for normal synaptic transmission and plasticity in the dentate gyrus of the rat hippocampus. Neuropharmacology 2012; 62:2373-87. [PMID: 22365983 DOI: 10.1016/j.neuropharm.2012.02.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 02/07/2012] [Accepted: 02/08/2012] [Indexed: 11/28/2022]
Abstract
Both in vivo and in vitro studies have shown that neurosteroids promote learning and memory by modulating synaptic functions in the hippocampus. However, we do not know to what degree endogenously synthesized neurosteroids contribute to the hippocampal synaptic functions. Cytochrome P450scc is the enzyme that converts cholesterol to pregnenolone (PREG), which is required for the biosynthesis of all other neurosteroids. To investigate the physiological roles of endogenous neurosteroids in synaptic functions, we electrophysiologically examined the effects of aminoglutethimide (AG), a selective inhibitor of P450scc, on the synaptic transmission and plasticity in the dentate gyrus of rat hippocampal slices. The application of AG (100 μM) decreased the slope of the field excitatory postsynaptic potentials (fEPSPs) in granule cells by 20-30% in 20 min through the modulation of postsynaptic AMPA receptors, while it did not affect the presynaptic properties, including the paired-pulse ratio and the probability of glutamate release from presynaptic terminals. The AG-induced depression was nearly completely rescued by exogenously applied 500 nM PREG or by 1 nM dehydroepiandrosterone sulfate (DHEAS), one of the neurosteroids synthesized from PREG, suggesting that the AG-induced depression was caused by the loss of DHEAS. AG also reduced NMDA receptor activity, and suppressed high-frequency stimulation (HFS)-induced long-term potentiation (LTP). These findings provide novel evidence that the endogenous neurosteroids locally synthesized in the brain are required to maintain the normal excitatory synaptic transmission and plasticity in the dentate gyrus of the rat hippocampus.
Collapse
Affiliation(s)
- Motoki Tanaka
- Department of Physiology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan.
| | | |
Collapse
|
161
|
Lebron-Milad K, Milad MR. Sex differences, gonadal hormones and the fear extinction network: implications for anxiety disorders. BIOLOGY OF MOOD & ANXIETY DISORDERS 2012; 2:3. [PMID: 22738383 PMCID: PMC3384233 DOI: 10.1186/2045-5380-2-3] [Citation(s) in RCA: 191] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 02/07/2012] [Indexed: 01/11/2023]
Abstract
Convergent data from rodents and human studies have led to the development of models describing the neural mechanisms of fear extinction. Key components of the now well-characterized fear extinction network include the amygdala, hippocampus, and medial prefrontal cortical regions. These models are fueling novel hypotheses that are currently being tested with much refined experimental tools to examine the interactions within this network. Lagging far behind, however, is the examination of sex differences in this network and how sex hormones influence the functional activity and reactivity of these brain regions in the context of fear inhibition. Indeed, there is a large body of literature suggesting that sex hormones, such as estrogen, do modulate neural plasticity within the fear extinction network, especially in the hippocampus.After a brief overview of the fear extinction network, we summarize what is currently known about sex differences in fear extinction and the influence of gonadal hormones on the fear extinction network. We then go on to propose possible mechanisms by which sex hormones, such as estrogen, may influence neural plasticity within the fear extinction network. We end with a discussion of how knowledge to be gained from developing this line of research may have significant ramifications towards the etiology, epidemiology and treatment of anxiety disorders.
Collapse
Affiliation(s)
- Kelimer Lebron-Milad
- Department of Psychiatry, Harvard Medical School & Massachusetts General Hospital, Boston, MA, USA.
| | | |
Collapse
|
162
|
Sanchez AM, Flamini MI, Polak K, Palla G, Spina S, Mannella P, Genazzani AD, Simoncini T. Actin cytoskeleton remodelling by sex steroids in neurones. J Neuroendocrinol 2012; 24:195-201. [PMID: 22103470 DOI: 10.1111/j.1365-2826.2011.02258.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cell morphology and its interaction with the extracellular environment are integrated processes involving a number of intracellular controllers orchestrating cytoskeletal proteins and their interaction with the cell membrane and anchorage proteins. Sex steroids are effective regulators of cell morphology and tissue organisation, and recent evidence indicates that this is obtained through the regulation of the actin cytoskeleton. Intriguingly, many of these regulatory actions related to cell morphology are achieved through the rapid, nonclassical signalling of sex steroid receptors to kinase cascades, independently from nuclear alteration of gene expression or protein synthesis. The identification of the mechanistic basis for these rapid actions on cell cytoskeleton has special relevance for the characterisation of the effects of sex steroids under physiological conditions, such as for the development of neurone/neurone interconnections and dendritic spine density. This is considered to be critical for gender-specific differences in brain function and dysfunction. Recent advancements in the characterisation of the molecular basis of the extranuclear signalling of sex steroids help to clarify the role of oestrogen and progesterone in the brain, and may turn out to be of relevance for clinical purposes. This review highlights the regulatory effects of oestrogens and progesterone on actin cytoskeleton and neurone morphology, as well as recent progresses in the characterisation of these mechanisms, providing insights and working hypotheses on possible clinical applications for the modulation of these pathways in the central nervous system.
Collapse
Affiliation(s)
- A M Sanchez
- Institute of Medicine and Experimental Biology of Cuyo, CCT-CONICET Mendoza, National University of Cuyo, Parque General San Martin s/n, Mendoza, Argentina
| | | | | | | | | | | | | | | |
Collapse
|
163
|
Grassi S, Frondaroli A, Scarduzio M, Dieni CV, Brecchia G, Boiti C, Pettorossi VE. Influence of sex and estrous cycle on synaptic responses of the medial vestibular nuclei in rats: role of circulating 17β-estradiol. Brain Res Bull 2011; 87:319-27. [PMID: 22127323 DOI: 10.1016/j.brainresbull.2011.11.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 11/08/2011] [Accepted: 11/15/2011] [Indexed: 11/30/2022]
Abstract
We investigated the possible influence of sex and estrous cycle on the synaptic responses of neurons in the medial vestibular nucleus (MVN) and their long-term modifications. In brain stem slices of male and female rats during proestrus (PE) and diestrus (DE), we evaluated the field potential evoked in the MVN by vestibular afferent stimulation. Here we find that in PE females the field potential had a lower threshold and higher amplitude than in DE females and in males and also that the stimulus-response curve was shifted to the left. Such difference is related to the level and cyclic fluctuation of circulating 17β-estradiol (E(2)). This is supported by the exogenous administration of E(2) in DE females and males, with low levels of circulating E(2) that enhanced the field potential amplitude to values close to those of PE females. Sex and estrous cycle also influence the MVN synaptic plasticity. This has been shown by investigating the effect of testosterone (T) on the induction of long-term effects, since T is the precursor for the neural synthesis of E(2) (estrogenic pathway), which is involved in the induction of fast long-term potentiation (LTP), or of 5α-dihydrotestosterone (DHT, androgenic pathway) which mediates slow LTP and long-term depression (LTD). We found that T mostly induced LTD in PE females and no effect in DE females, while it only provoked fast LTP in males. We suggest that high level of circulating E(2) may interfere with the conversion of T, by inhibiting the neural estrogenic pathway and facilitating the androgenic one. On the whole these results demonstrate an influence of circulating E(2) on vestibular synaptic transmission and plasticity that in some cases may contribute to the sex and menstrual cycle dependence of symptoms in human vestibular pathology.
Collapse
Affiliation(s)
- Silvarosa Grassi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Via del Giochetto, I-06126 Perugia, Italy.
| | | | | | | | | | | | | |
Collapse
|
164
|
Spencer-Segal JL, Tsuda MC, Mattei L, Waters EM, Romeo RD, Milner TA, McEwen BS, Ogawa S. Estradiol acts via estrogen receptors alpha and beta on pathways important for synaptic plasticity in the mouse hippocampal formation. Neuroscience 2011; 202:131-46. [PMID: 22133892 DOI: 10.1016/j.neuroscience.2011.11.035] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 10/25/2011] [Accepted: 11/15/2011] [Indexed: 01/07/2023]
Abstract
Estradiol affects hippocampal-dependent spatial memory and underlying structural and electrical synaptic plasticity in female mice and rats. Using estrogen receptor (ER) alpha and beta knockout mice and wild-type littermates, we investigated the role of ERs in estradiol effects on multiple pathways important for hippocampal plasticity and learning. Six hours of estradiol administration increased immunoreactivity for phosphorylated Akt throughout the hippocampal formation, whereas 48 h of estradiol increased immunoreactivity for phosphorylated TrkB receptor. Estradiol effects on phosphorylated Akt and TrkB immunoreactivities were abolished in ER alpha and ER beta knockout mice. Estradiol also had distinct effects on immunoreactivity for post-synaptic density 95 (PSD-95) and brain derived-neurotrophic factor (BDNF) mRNA in ER alpha and beta knockout mice. Thus, estradiol acts through both ERs alpha and beta in several subregions of the hippocampal formation. The different effects of estradiol at 6 and 48 h indicate that several mechanisms of estrogen receptor signaling contribute to this female hormone's influence on hippocampal synaptic plasticity. By further delineating these mechanisms, we will better understand and predict the effects of endogenous and exogenous ovarian steroids on mood, cognition, and other hippocampal-dependent behaviors.
Collapse
Affiliation(s)
- J L Spencer-Segal
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA.
| | | | | | | | | | | | | | | |
Collapse
|
165
|
Xu X, Li T, Luo Q, Hong X, Xie L, Tian D. Bisphenol-A rapidly enhanced passive avoidance memory and phosphorylation of NMDA receptor subunits in hippocampus of young rats. Toxicol Appl Pharmacol 2011; 255:221-8. [DOI: 10.1016/j.taap.2011.06.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 06/27/2011] [Accepted: 06/28/2011] [Indexed: 02/01/2023]
|
166
|
Fester L, Prange-Kiel J, Jarry H, Rune GM. Estrogen synthesis in the hippocampus. Cell Tissue Res 2011; 345:285-94. [DOI: 10.1007/s00441-011-1221-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 07/17/2011] [Indexed: 12/31/2022]
|
167
|
Ooishi Y, Mukai H, Hojo Y, Murakami G, Hasegawa Y, Shindo T, Morrison JH, Kimoto T, Kawato S. Estradiol rapidly rescues synaptic transmission from corticosterone-induced suppression via synaptic/extranuclear steroid receptors in the hippocampus. ACTA ACUST UNITED AC 2011; 22:926-36. [PMID: 21725036 DOI: 10.1093/cercor/bhr164] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We investigated rapid protection effect by estradiol on corticosterone (CORT)-induced suppression of synaptic transmission. Rapid suppression by 1 μM CORT of long-term potentiation (LTP) at CA3-CA1 synapses was abolished via coperfusion of 1 nM estradiol. N-methyl-D-aspartate (NMDA) receptor-derived field excitatory postsynaptic potential (NMDA-R-fEPSP) was used to analyze the mechanisms of these events. Estradiol abolished CORT-induced suppression of NMDA-R-fEPSP slope. This CORT-induced suppression was abolished by calcineurin inhibitor, and the rescue effect by estradiol on the CORT-induced suppression was inhibited by mitogen-activated protein (MAP) kinase inhibitor. The CORT-induced suppressions of LTP and NMDA-R-fEPSP slope were abolished by glucocorticoid receptor (GR) antagonist, and the restorative effects by estradiol on these processes were mimicked by estrogen receptor α (ERα) and ERβ agonists. Taken together, estradiol rapidly rescued LTP and NMDA-R-fEPSP slope from CORT-induced suppressions. A GR→calcineurin pathway is involved in these suppressive effects. The rescue effects by estradiol are driven via ERα or ERβ→MAP kinase pathway. Synaptic/extranuclear GR, ERα, and ERβ probably participate in these rapid events. Mass-spectrometric analysis determined that acute hippocampal slices used for electrophysiological measurements contained 0.48 nM estradiol less than exogenously applied 1 nM. In vivo physiological level of 8 nM estradiol could protect the intact hippocampus against acute stress-induced neural suppression.
Collapse
Affiliation(s)
- Yuuki Ooishi
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
168
|
Grassi S, Tozzi A, Costa C, Tantucci M, Colcelli E, Scarduzio M, Calabresi P, Pettorossi VE. Neural 17β-estradiol facilitates long-term potentiation in the hippocampal CA1 region. Neuroscience 2011; 192:67-73. [PMID: 21749911 DOI: 10.1016/j.neuroscience.2011.06.078] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 06/23/2011] [Accepted: 06/28/2011] [Indexed: 10/18/2022]
Abstract
In the hippocampal formation many neuromodulators are possibly implied in the synaptic plasticity such as the long-term potentiation (LTP) induced by high-frequency stimulation (HFS) of afferent fibers. We investigated the involvement of locally synthesized neural 17β-estradiol (nE(2)) in the induction of HFS-LTP in hippocampal slices from male rats by stimulating the Schaffer collateral fibers and recording the evoked field excitatory postsynaptic potential (fEPSP) in the CA1 region. We demonstrated that either the blockade of nE(2) synthesis by the aromatase inhibitor letrozole, or the antagonism of E(2) receptors (ERs) by ICI 182,780 did not prevent the induction of HFS-LTP, but reduced its amplitude by ∼60%, without influencing its maintenance. Moreover, letrozole and ICI 182,780 did not affect the first short-term post-tetanic component of LTP and the paired-pulse facilitation (PPF). These findings demonstrate that nE(2) plays an important role in the induction phase of HFS-dependent LTP. Since the basal responses were not affected by the blocking agents, we suggest that the synthesis of nE(2) is induced or enhanced by HFS through aromatase activation. In this context, the local production of nE(2) seems to be a very effective mechanism to modulate the amplitude of LTP.
Collapse
Affiliation(s)
- S Grassi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Via del Giochetto, I-06126 Perugia, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
169
|
Estrogen receptors beta and alpha have specific pro- and anti-nociceptive actions. Neuroscience 2011; 184:172-82. [DOI: 10.1016/j.neuroscience.2011.02.057] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 02/24/2011] [Accepted: 02/26/2011] [Indexed: 11/18/2022]
|
170
|
Bolay H, Berman NEJ, Akcali D. Sex-Related Differences in Animal Models of Migraine Headache. Headache 2011; 51:891-904. [DOI: 10.1111/j.1526-4610.2011.01903.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
171
|
Frick KM, Zhao Z, Fan L. The epigenetics of estrogen: epigenetic regulation of hormone-induced memory enhancement. Epigenetics 2011; 6:675-80. [PMID: 21593594 DOI: 10.4161/epi.6.6.16177] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Epigenetic processes have been implicated in everything from cell proliferation to maternal behavior. Epigenetic alterations, including histone alterations and DNA methylation, have also been shown to play critical roles in the formation of some types of memory, and in the modulatory effects that factors, such as stress, drugs of abuse and environmental stimulation, have on the brain and memory function. Recently, we demonstrated that the ability of the sex-steroid hormone 17β-estradiol (E(2)) to enhance memory formation is dependent on histone acetylation and DNA methylation, a finding that has important implications for understanding how hormones influence cognition in adulthood and aging. In this article, we provide an overview of the literature demonstrating that epigenetic processes and E(2) influence memory, describe our findings indicating that epigenetic alterations regulate E(2)-induced memory enhancement, and discuss directions for future work on the epigenetics of estrogen.
Collapse
Affiliation(s)
- Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
| | | | | |
Collapse
|
172
|
The mouse primary visual cortex is a site of production and sensitivity to estrogens. PLoS One 2011; 6:e20400. [PMID: 21647225 PMCID: PMC3101258 DOI: 10.1371/journal.pone.0020400] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 04/25/2011] [Indexed: 12/21/2022] Open
Abstract
The classic female estrogen, 17β-estradiol (E2), has been repeatedly shown to affect the perceptual processing of visual cues. Although gonadal E2 has often been thought to influence these processes, the possibility that central visual processing may be modulated by brain-generated hormone has not been explored. Here we show that estrogen-associated circuits are highly prevalent in the mouse primary visual cortex (V1). Specifically, we cloned aromatase, a marker for estrogen-producing neurons, and the classic estrogen receptors (ERs) ERα and ERβ, as markers for estrogen-responsive neurons, and conducted a detailed expression analysis via in-situ hybridization. We found that both monocular and binocular V1 are highly enriched in aromatase- and ER-positive neurons, indicating that V1 is a site of production and sensitivity to estrogens. Using double-fluorescence in-situ hybridization, we reveal the neurochemical identity of estrogen-producing and -sensitive cells in V1, and demonstrate that they constitute a heterogeneous neuronal population. We further show that visual experience engages a large population of aromatase-positive neurons and, to a lesser extent, ER-expressing neurons, suggesting that E2 levels may be locally regulated by visual input in V1. Interestingly, acute episodes of visual experience do not affect the density or distribution of estrogen-associated circuits. Finally, we show that adult mice dark-reared from birth also exhibit normal distribution of aromatase and ERs throughout V1, suggesting that the implementation and maintenance of estrogen-associated circuits is independent of visual experience. Our findings demonstrate that the adult V1 is a site of production and sensitivity to estrogens, and suggest that locally-produced E2 may shape visual cortical processing.
Collapse
|
173
|
Brain-generated estradiol drives long-term optimization of auditory coding to enhance the discrimination of communication signals. J Neurosci 2011; 31:3271-89. [PMID: 21368039 DOI: 10.1523/jneurosci.4355-10.2011] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Auditory processing and hearing-related pathologies are heavily influenced by steroid hormones in a variety of vertebrate species, including humans. The hormone estradiol has been recently shown to directly modulate the gain of central auditory neurons, in real time, by controlling the strength of inhibitory transmission via a nongenomic mechanism. The functional relevance of this modulation, however, remains unknown. Here we show that estradiol generated in the songbird homolog of the mammalian auditory association cortex, rapidly enhances the effectiveness of the neural coding of complex, learned acoustic signals in awake zebra finches. Specifically, estradiol increases mutual information rates, coding efficiency, and the neural discrimination of songs. These effects are mediated by estradiol's modulation of both the rate and temporal coding of auditory signals. Interference with the local action or production of estradiol in the auditory forebrain of freely behaving animals disrupts behavioral responses to songs, but not to other behaviorally relevant communication signals. Our findings directly show that estradiol is a key regulator of auditory function in the adult vertebrate brain.
Collapse
|
174
|
Pettorossi VE, Frondaroli A, Grassi S. Cyclic estrogenic fluctuation influences synaptic transmission of the medial vestibular nuclei in female rats. Acta Otolaryngol 2011; 131:434-9. [PMID: 21189054 DOI: 10.3109/00016489.2010.536992] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION The estrous cycle in female rats influences the basal synaptic responsiveness and plasticity of the medial vestibular nucleus (MVN) neurons through different levels of circulating 17β-estradiol (cE(2)). OBJECTIVE The aim of this study was to verify, in the female rat, whether cyclic fluctuations of cE(2) influence long-term synaptic effects induced by high frequency afferent stimulation (HFS) in the MVN, since we found that HFS in the male rat induces fast long-term potentiation (fLTP), which depends on the neural synthesis of E(2) (nE(2)) from testosterone (T). METHODS We analyzed the field potential (FP) evoked in the MVN by vestibular afferent stimulation, under basal conditions, and after HFS, in brainstem slices of female rats during high levels (proestrus, PE) and low levels (diestrus, DE) of cE(2). Selective blocking agents of converting T enzymes were used. RESULTS Unlike in the male rat, HFS induced three effects: fLTP through T conversion into E(2), and slow LTP (sLTP) and long-term depression (LTD), through T conversion into DHT. The occurrence of these effects depended on the estrous cycle phase: the frequency of fLTP was higher in DE, and those of sLTP and LTD were higher in PE. Conversely, the basal FP was also higher in PE than in DE.
Collapse
Affiliation(s)
- Vito E Pettorossi
- Department of Internal Medicine, Section of Human Physiology, University of Perugia, Italy.
| | | | | |
Collapse
|
175
|
Phan A, Lancaster KE, Armstrong JN, MacLusky NJ, Choleris E. Rapid effects of estrogen receptor α and β selective agonists on learning and dendritic spines in female mice. Endocrinology 2011; 152:1492-502. [PMID: 21285321 DOI: 10.1210/en.2010-1273] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Estrogen receptor (ER) agonists rapidly affect neural plasticity within 1 h, suggesting they play a functional role in learning and memory. However, behavioral learning experiments on such a rapid time scale are lacking. Therefore we investigated whether the ERα agonist propyl pyrazole triol (PPT) and ERβ agonist diarylpropionitrile (DPN) could affect social recognition, object recognition, or object placement learning within 40 min of drug administration. At the same time, we examined their effects on CA1 hippocampal dendritic spines. Ovariectomized female CD1 mice were administered a range of PPT or DPN doses (0, 30, 50, 75, or 150 μg/mouse). PPT at the middle doses improved social recognition, facilitated object recognition and placement at a dose of 75 μg, and increased dendritic spine density in the stratum radiatum and lacunosum-moleculare. In contrast, DPN impaired social recognition at higher doses, did not affect object recognition, but slightly facilitated object placement learning at the 75-μg dose. DPN did not affect spines in the stratum radiatum but decreased spine density and increased spine length in the lacunosum-moleculare. This suggests that rapid estrogen-mediated learning enhancements may predominantly be mediated through ERα, while the effects of DPN are weaker and may depend on the learning paradigm. The role of ERα and ERβ in learning and memory may vary depending on the timing of drug administration, as genomic studies often implicate ERβ in enhancing effects on learning and memory. To our knowledge, this is the first report of estrogens' effects on learning within such a short time frame.
Collapse
Affiliation(s)
- Anna Phan
- Department of Psychology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | | | | | | | | |
Collapse
|
176
|
Waters EM, Yildirim M, Janssen WGM, Lou WYW, McEwen BS, Morrison JH, Milner TA. Estrogen and aging affect the synaptic distribution of estrogen receptor β-immunoreactivity in the CA1 region of female rat hippocampus. Brain Res 2011; 1379:86-97. [PMID: 20875808 PMCID: PMC3046233 DOI: 10.1016/j.brainres.2010.09.069] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 09/17/2010] [Accepted: 09/17/2010] [Indexed: 11/29/2022]
Abstract
Estradiol (E) mediates increased synaptogenesis in the hippocampal CA1 stratum radiatum (sr) and enhances memory in young and some aged female rats, depending on dose and age. Young female rats express more estrogen receptor α (ERα) immunolabeling in CA1sr spine synapse complexes than aged rats and ERα regulation is E sensitive in young but not aged rats. The current study examined whether estrogen receptor β (ERβ) expression in spine synapse complexes may be altered by age or E treatment. Young (3-4 months) and aged (22-23 months) female rats were ovariectomized 7 days prior to implantation of silastic capsules containing either vehicle (cholesterol) or E (10% in cholesterol) for 2 days. ERβ immunoreactivity (ir) in CA1sr was quantitatively analyzed using post-embedding electron microscopy. ERβ-ir was more prominent post-synaptically than pre-synaptically and both age and E treatment affected its synaptic distribution. While age decreased the spine synaptic complex localization of ERβ-ir (i.e., within 60 nm of the pre- and post-synaptic membranes), E treatment increased synaptic ERβ in both young and aged rats. In addition, the E treatment, but not age, increased dendritic shaft labeling. This data demonstrates that like ERα the levels of ERβ-ir decrease in CA1 axospinous synapses with age, however, unlike ERα the levels of ERβ-ir increase in these synapses in both young and aged rats in response to E. This suggests that synaptic ERβ may be a more responsive target to E, particularly in aged females.
Collapse
Affiliation(s)
- Elizabeth M Waters
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065, USA.
| | | | | | | | | | | | | |
Collapse
|
177
|
Mechanisms of estrogens' dose-dependent neuroprotective and neurodamaging effects in experimental models of cerebral ischemia. Int J Mol Sci 2011; 12:1533-62. [PMID: 21673906 PMCID: PMC3111617 DOI: 10.3390/ijms12031533] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 02/10/2011] [Accepted: 02/22/2011] [Indexed: 02/08/2023] Open
Abstract
Ever since the hypothesis was put forward that estrogens could protect against cerebral ischemia, numerous studies have investigated the mechanisms of their effects. Despite initial studies showing ameliorating effects, later trials in both humans and animals have yielded contrasting results regarding the fundamental issue of whether estrogens are neuroprotective or neurodamaging. Therefore, investigations of the possible mechanisms of estrogen actions in brain ischemia have been difficult to assess. A recently published systematic review from our laboratory indicates that the dichotomy in experimental rat studies may be caused by the use of insufficiently validated estrogen administration methods resulting in serum hormone concentrations far from those intended, and that physiological estrogen concentrations are neuroprotective while supraphysiological concentrations augment the damage from cerebral ischemia. This evidence offers a new perspective on the mechanisms of estrogens’ actions in cerebral ischemia, and also has a direct bearing on the hormone replacement therapy debate. Estrogens affect their target organs by several different pathways and receptors, and the mechanisms proposed for their effects on stroke probably prevail in different concentration ranges. In the current article, previously suggested neuroprotective and neurodamaging mechanisms are reviewed in a hormone concentration perspective in an effort to provide a mechanistic framework for the dose-dependent paradoxical effects of estrogens in stroke. It is concluded that five protective mechanisms, namely decreased apoptosis, growth factor regulation, vascular modulation, indirect antioxidant properties and decreased inflammation, and the proposed damaging mechanism of increased inflammation, are currently supported by experiments performed in optimal biological settings.
Collapse
|
178
|
Barron AM, Hojo Y, Mukai H, Higo S, Ooishi Y, Hatanaka Y, Ogiue-Ikeda M, Murakami G, Kimoto T, Kawato S. Regulation of synaptic plasticity by hippocampus synthesized estradiol. Horm Mol Biol Clin Investig 2011; 7:361-75. [PMID: 25961274 DOI: 10.1515/hmbci.2011.118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 07/21/2011] [Indexed: 01/29/2023]
Abstract
Estradiol is synthesized from cholesterol in hippocampal neurons of adult rats by cytochrome P450 and hydroxysteroid dehydrogenase enzymes. These enzymes are expressed in the glutamatergic neurons of the hippocampus. Surprisingly, the concentration of estradiol and androgen in the hippocampus is significantly higher than that in circulation. Locally synthesized estradiol rapidly and potently modulates synaptic plasticity within the hippocampus. E2 rapidly potentiates long-term depression and induces spinogenesis through synaptic estrogen receptors and kinases. The rapid effects of estradiol are followed by slow genomic effects mediated by both estrogen receptors located at the synapse and nucleus, modulating long-term potentiation and promoting the formation of new functional synaptic contacts. Age-related changes in hippocampally derived estradiol synthesis and distribution of estrogen receptors may alter synaptic plasticity, and could potentially contribute to age-related cognitive decline. Understanding factors which regulate hippocampal estradiol synthesis could lead to the identification of alternatives to conventional hormone therapy to protect against age-related cognitive decline.
Collapse
|
179
|
Foy MR. Ovarian hormones, aging and stress on hippocampal synaptic plasticity. Neurobiol Learn Mem 2011; 95:134-44. [PMID: 21081173 PMCID: PMC3045646 DOI: 10.1016/j.nlm.2010.11.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Revised: 10/13/2010] [Accepted: 11/04/2010] [Indexed: 01/28/2023]
Abstract
The ovarian steroid hormones estradiol and progesterone regulate a wide variety of non-reproductive functions in the central nervous system by interacting with molecular and cellular processes. A growing literature from studies using rodent models suggests that 17β-estradiol, the most potent of the biologically relevant estrogens, enhances synaptic transmission and the magnitude of long-term potentiation recorded from in vitro hippocampal slices. In contrast, progesterone has been shown to decrease synaptic transmission and reduce hippocampal long-term potentiation in this model system. Hippocampal long-term depression, another form of synaptic plasticity, occurs more prominently in slices from aged rats. A decrease in long-term potentiation magnitude has been recorded in hippocampal slices from both adult and aged rats behaviorally stressed just prior to hippocampal slice tissue preparation and electrophysiological recording. 17β-estradiol modifies synaptic plasticity in both adult and aged rats, whether behaviorally stressed or not by enhancing long-term potentiation and attenuating long-term depression. The studies discussed in this review provide an understanding of new approaches used to investigate the protective effects of ovarian hormones against aging and stress, and how these hormones impact age and stress-related learning and memory dysfunction.
Collapse
Affiliation(s)
- Michael R Foy
- Department of Psychology, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA 90045, USA.
| |
Collapse
|
180
|
Logan SM, Sarkar SN, Zhang Z, Simpkins JW. Estrogen-induced signaling attenuates soluble Aβ peptide-mediated dysfunction of pathways in synaptic plasticity. Brain Res 2011; 1383:1-12. [PMID: 21262203 DOI: 10.1016/j.brainres.2011.01.038] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 01/11/2011] [Accepted: 01/12/2011] [Indexed: 11/26/2022]
Abstract
Neuromodulation of synaptic plasticity by 17β-estradiol (E2) is thought to influence information processing and storage in the cortex and hippocampus. Because E2 rapidly affects cortical memory and synaptic plasticity, we examined its effects on phosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII), extracellular signal-regulated kinase (ERK), and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) [AMPA-type glutamate receptor subunit 1 (GluR1 subunit)], all of which are important for the induction and maintenance of synaptic plasticity and memory. Acute E2 treatment resulted in an increased temporal and spatial phosphorylation pattern of CaMKII, ERK, and AMPAR (GluR1 subunit). By using inhibitors, we were able to attribute GluR1 phosphorylation to CaMKII at serine 831, and we also found that E2 treatment increased GluR1 insertion into the surface membrane. Because soluble amyloid-beta (Aβ) oligomers inhibit CaMKII and ERK activation, which is necessary for synaptic plasticity, we also tested E2's ability to ameliorate Aβ-induced dysfunction of synaptic plasticity. We found that estrogen treatment in neuronal culture, slice culture, and in vivo, ameliorated Aβ oligomer-induced inhibition of CaMKII, ERK, and AMPAR phosphorylation, and also ameliorated the Aβ oligomer-induced reduction of dendritic spine density in a CaMKII-dependent manner. These phosphorylation events are correlated with the early stage of inhibitory avoidance learning, and our data show that E2 improved inhibitory avoidance memory deficits in animals treated with soluble Aβ oligomers. This study identifies E2-induced signaling that attenuates soluble Aβ peptide-mediated dysfunction of pathways in synaptic plasticity.
Collapse
Affiliation(s)
- Shaun M Logan
- Department of Pharmacology & Neuroscience, Institute for Aging and Alzheimer's Disease Research, University of North Texas Health Science Center at Fort Worth, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, USA
| | | | | | | |
Collapse
|
181
|
Wu TW, Chen S, Brinton RD. Membrane estrogen receptors mediate calcium signaling and MAP kinase activation in individual hippocampal neurons. Brain Res 2011; 1379:34-43. [PMID: 21241678 DOI: 10.1016/j.brainres.2011.01.034] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2011] [Indexed: 11/19/2022]
Abstract
Previously we demonstrated that 17β-Estradiol (E2) induced rapid Ca(2+) influx via L-type calcium channel activation, which was required for activation of Src/ERK/CREB/Bcl2 signaling cascade and subsequent induction of neuroprotective and neurotrophic responses in rat hippocampal and cortical neurons (Wu et al., 2005; Zhao et al., 2005). The current study determined the presence and specificity of membrane E2 binding sites and the functional consequence of E2 binding to membrane receptors in individual neurons. Using E2-BSA-FITC (fluorescein isothiocyanate) macromolecular complex, membrane E2 binding sites were observed in hippocampal neurons. Punctate FITC signal was observed on plasma membrane of soma and neuronal processes in E2-BSA-FITC binding neurons. No membrane binding was observed with BSA-FITC. Specificity of binding was demonstrated by competition with excess un-conjugated E2. An ERa specific agonist, PPT, and an ERb agonist, DPN, partially competed for E2-BSA-FITC binding. Imaging of intracellular Ca(2+) ([Ca(2+)]i) in live neurons, revealed rapid Ca(2+) responses in E2-BSA-FITC binding neurons within minutes that culminated in a greater [Ca(2+)]i rise and [Ca(2+)]i spikes at >20 min. The same neurons in which E2-BSA-FITC induced a [Ca(2+)]i rise also exhibited activated pERK (extracellular signal-regulated kinase) that was translocated to the nucleus. Immunofluorescent analyses demonstrated that both excitatory and inhibitory neuronal markers labeled subpopulations of E2-BSA-FITC binding neurons. All E2-BSA-FITC binding neurons expressed L-type calcium channels. These results demonstrate, at a single cell level, that E2 membrane receptors mediate the rapid signaling cascades required for E2 neuroprotective and neurotrophic effects in hippocampal neurons. These results are discussed with respect to therapeutic targets of estrogen therapy in brain.
Collapse
Affiliation(s)
- Tzu-Wei Wu
- University of Southern California, Pharmaceutical Sciences Center, Los Angeles, CA 90089-9121, USA.
| | | | | |
Collapse
|
182
|
Estradiol acutely potentiates hippocampal excitatory synaptic transmission through a presynaptic mechanism. J Neurosci 2011; 30:16137-48. [PMID: 21123560 DOI: 10.1523/jneurosci.4161-10.2010] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although recent evidence suggests that the hippocampus is a source of 17β-estradiol (E2), the physiological role of this neurosteroid E2, as distinct from ovarian E2, is unknown. One likely function of neurosteroid E2 is to acutely potentiate excitatory synaptic transmission, but the mechanism of this effect is not well understood. Using whole-cell voltage-clamp recording of synaptically evoked EPSCs in adult rat hippocampal slices, we show that, in contrast to the conclusions of previous studies, E2 potentiates excitatory transmission through a presynaptic mechanism. We find that E2 acutely potentiates EPSCs by increasing the probability of glutamate release specifically at inputs with low initial release probability. This effect is mediated by estrogen receptor β (ERβ) acting as a monomer, whereas ERα is not required. We further show that the E2-induced increase in glutamate release is attributable primarily to increased individual vesicle release probability and is associated with higher average cleft glutamate concentration. These two findings together argue strongly that E2 promotes multivesicular release, which has not been shown before in the adult hippocampus. The rapid time course of acute EPSC potentiation and its concentration dependence suggest that locally synthesized neurosteroid E2 may activate this effect in vivo.
Collapse
|
183
|
Roepke TA, Ronnekleiv OK, Kelly MJ. Physiological consequences of membrane-initiated estrogen signaling in the brain. Front Biosci (Landmark Ed) 2011; 16:1560-73. [PMID: 21196248 DOI: 10.2741/3805] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many of the actions of 17beta-estradiol (E2) in the central nervous system (CNS) are mediated via the classical nuclear steroid receptors, ER(alpha) and ERbeta, which interact with the estrogen response element to modulate gene expression. In addition to the nuclear-initiated estrogen signaling, E2 signaling in the brain can occur rapidly within minutes prior to any sufficient effects on transcription of relevant genes. These rapid, membrane-initiated E2 signaling mechanisms have now been characterized in many brain regions, most importantly in neurons of the hypothalamus and hippocampus. Furthermore, our understanding of the physiological effects of membrane-initiated pathways is now a major field of interest in the hypothalamic control of reproduction, energy balance, thermoregulation and other homeostatic functions as well as the effects of E2 on physiological and pathophysiological functions of the hippocampus. Membrane signaling pathways impact neuronal excitability, signal transduction, cell death, neurotransmitter release and gene expression. This review will summarize recent findings on membrane-initiated E2 signaling in the hypothalamus and hippocampus and its contribution to the control of physiological and behavioral functions.
Collapse
Affiliation(s)
- Troy A Roepke
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239, USA
| | | | | |
Collapse
|
184
|
Boulware MI, Kent BA, Frick KM. The impact of age-related ovarian hormone loss on cognitive and neural function. Curr Top Behav Neurosci 2011; 10:165-84. [PMID: 21533680 DOI: 10.1007/7854_2011_122] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
On average, women now live one-third of their lives after menopause. Because menopause has been associated with an elevated risk of dementia, an increasing body of research has studied the effects of reproductive senescence on cognitive function. Compelling evidence from humans, nonhuman primates, and rodents suggests that ovarian sex-steroid hormones can have rapid and profound effects on memory, attention, and executive function, and on regions of the brain that mediate these processes, such as the hippocampus and prefrontal cortex. This chapter will provide an overview of studies in humans, nonhuman primates, and rodents that examine the effects of ovarian hormone loss and hormone replacement on cognitive functions mediated by the hippocampus and prefrontal cortex. For humans and each animal model, we outline the effects of aging on reproductive function, describe how ovarian hormones (primarily estrogens) modulate hippocampal and prefrontal physiology, and discuss the effects of both reproductive aging and hormone treatment on cognitive function. Although this review will show that much has been learned about the effects of reproductive senescence on cognition, many critical questions remain for future investigation.
Collapse
Affiliation(s)
- Marissa I Boulware
- Department of Psychology, University of Wisconsin-Milwaukee, 2441 E. Hartford Ave, Milwaukee, WI 53211, USA
| | | | | |
Collapse
|
185
|
Hojo Y, Higo S, Kawato S, Hatanaka Y, Ooishi Y, Murakami G, Ishii H, Komatsuzaki Y, Ogiue-Ikeda M, Mukai H, Kimoto T. Hippocampal synthesis of sex steroids and corticosteroids: essential for modulation of synaptic plasticity. Front Endocrinol (Lausanne) 2011; 2:43. [PMID: 22701110 PMCID: PMC3356120 DOI: 10.3389/fendo.2011.00043] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 09/13/2011] [Indexed: 11/13/2022] Open
Abstract
Sex steroids play essential roles in the modulation of synaptic plasticity and neuroprotection in the hippocampus. Accumulating evidence shows that hippocampal neurons synthesize both estrogen and androgen. Recently, we also revealed the hippocampal synthesis of corticosteroids. The accurate concentrations of these hippocampus-synthesized steroids are determined by liquid chromatography-tandem mass-spectrometry in combination with novel derivatization. The hippocampal levels of 17β-estradiol (E2), testosterone (T), dihydrotestosterone (DHT), and corticosterone (CORT), are 5-15 nM, and these levels are sufficient to modulate synaptic plasticity. Hippocampal E2 modulates memory-related synaptic plasticity not only slowly/genomically but also rapidly/non-genomically. Slow actions of E2 occur via classical nuclear receptors (ERα or ERβ), while rapid E2 actions occur via synapse-localized or extranuclear ERα or ERβ. Nanomolar concentrations of E2 change rapidly the density and morphology of spines in hippocampal neurons. ERα, but not ERβ, drives this enhancement/suppression of spinogenesis in adult animals. Nanomolar concentrations of androgens (T and DHT) and CORT also increase the spine density. Kinase networks are involved downstream of ERα and androgen receptor. Newly developed Spiso-3D mathematical analysis is useful to distinguish these complex effects by sex steroids and kinases. Significant advance has been achieved in investigations of rapid modulation by E2 of the long-term depression or the long-term potentiation.
Collapse
Affiliation(s)
- Yasushi Hojo
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
- Core Research for Evolutional Science and Technology Project of Japan Science and Technology Agency, The University of TokyoTokyo, Japan
- Bioinformatics Project of Japan Science and Technology Agency, The University of TokyoTokyo, Japan
| | - Shimpei Higo
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
| | - Suguru Kawato
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
- Core Research for Evolutional Science and Technology Project of Japan Science and Technology Agency, The University of TokyoTokyo, Japan
- Bioinformatics Project of Japan Science and Technology Agency, The University of TokyoTokyo, Japan
- *Correspondence: Suguru Kawato, Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan. e-mail:
| | - Yusuke Hatanaka
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
| | - Yuuki Ooishi
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
| | - Gen Murakami
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
- Bioinformatics Project of Japan Science and Technology Agency, The University of TokyoTokyo, Japan
| | - Hirotaka Ishii
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
| | - Yoshimasa Komatsuzaki
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
| | - Mari Ogiue-Ikeda
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
- Project of Special Coordinate Funds for Promoting Science and Technology, The University of TokyoJapan
| | - Hideo Mukai
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
- Core Research for Evolutional Science and Technology Project of Japan Science and Technology Agency, The University of TokyoTokyo, Japan
- Bioinformatics Project of Japan Science and Technology Agency, The University of TokyoTokyo, Japan
| | - Tetsuya Kimoto
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
- Core Research for Evolutional Science and Technology Project of Japan Science and Technology Agency, The University of TokyoTokyo, Japan
- Bioinformatics Project of Japan Science and Technology Agency, The University of TokyoTokyo, Japan
| |
Collapse
|
186
|
Ziegler SG, Thornton JE. Low luteinizing hormone enhances spatial memory and has protective effects on memory loss in rats. Horm Behav 2010; 58:705-13. [PMID: 20691694 DOI: 10.1016/j.yhbeh.2010.07.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 06/11/2010] [Accepted: 07/25/2010] [Indexed: 11/16/2022]
Abstract
Though several studies have suggested that estradiol improves hippocampal-dependent spatial memory, the effects of other hormones in the hypothalamic-pituitary-gonadal axis on memory have largely been ignored. Estradiol and luteinizing hormone (LH) are generally inversely related and LH may significantly affect spatial memory. Ovariectomized (ovx) rats treated with Antide (a gonadotropin releasing hormone receptor antagonist) had low LH levels and showed enhanced spatial memory, comparable to treatment with estradiol. Antide-treated ovx females retained spatial memory longer than estradiol-treated ovx females. Deficits in spatial memory are a primary symptom of neurodegenerative disorders including Alzheimer's disease (AD). Treatment with Antide prevented spatial memory deficits in a neurotoxin-induced model typical of early AD. These data suggest that memory impairments seen in female rats after ovariectomy or women after menopause may be due to high LH levels and that a reduction in LH enhances memory. These results also implicate an LH lowering agent as a potential preventative therapy for AD.
Collapse
Affiliation(s)
- Shira G Ziegler
- Neuroscience Department, Oberlin College, Oberlin, OH 44074, USA
| | | |
Collapse
|
187
|
Aloisi AM, Ceccarelli I, Fiorenzani P, Maddalena M, Rossi A, Tomei V, Sorda G, Danielli B, Rovini M, Cappelli A, Anzini M, Giordano A. Aromatase and 5-alpha reductase gene expression: modulation by pain and morphine treatment in male rats. Mol Pain 2010; 6:69. [PMID: 20977699 PMCID: PMC2978140 DOI: 10.1186/1744-8069-6-69] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 10/26/2010] [Indexed: 01/18/2023] Open
Abstract
Background The steroid hormone testosterone has been found to be greatly reduced by opioids in different experimental and clinical conditions. The purpose of this study on male rats was to determine the effects of a single injection of morphine (5 mg/Kg) on persistent pain (formalin test) and the single or combined effects on p450-aromatase and 5-alpha reductase type 1 mRNA expression in the brain, liver and testis. Testosterone was determined in the plasma and in the brain, morphine was assayed in the plasma. Results In the morphine-treated rats, there were increases of 5-alpha reductase mRNA expression in the liver and aromatase mRNA expression in the brain and gonads. Morphine was detected in the blood of all morphine-treated rats even though there were no clear analgesic affects in the formalin-treated animals three hours after treatment. Testosterone was greatly reduced in the plasma and brain in morphine-treated subjects. Conclusions It appears that morphine administration can induce long-lasting genomic effects in different body areas which contribute to the strong central and peripheral testosterone levels. These changes were not always accompanied by behavioral modifications.
Collapse
Affiliation(s)
- Anna Maria Aloisi
- Department of Physiology, Neuroscience and Applied Physiology Unit, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
188
|
Mukai H, Kimoto T, Hojo Y, Kawato S, Murakami G, Higo S, Hatanaka Y, Ogiue-Ikeda M. Modulation of synaptic plasticity by brain estrogen in the hippocampus. Biochim Biophys Acta Gen Subj 2010; 1800:1030-44. [DOI: 10.1016/j.bbagen.2009.11.002] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 10/15/2009] [Accepted: 11/02/2009] [Indexed: 12/31/2022]
|
189
|
The muscarinic long-term enhancement of NMDA and AMPA receptor-mediated transmission at Schaffer collateral synapses develop through different intracellular mechanisms. J Neurosci 2010; 30:11032-42. [PMID: 20720110 DOI: 10.1523/jneurosci.1848-10.2010] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We had described a muscarinic-mediated long-term synaptic enhancement at Schaffer collateral synapses caused by the insertion of AMPARs in spines of rat hippocampal CA1 pyramidal neurons that requires Ca(2+) release from IP3-sensitive stores (Fernández de Sevilla et al., 2008). We now show that this AMPA-mediated LTP(IP3) is precisely matched by an amplification of NMDAR-mediated transmission. The enhanced AMPAR transmission involves SNARE protein activity and CaMKII activation. The amplification of NMDA transmission requires combined CaMKII, PKC, and SRC kinase activity without detectable surface incorporation of NMDARs, suggesting that changes in receptor properties mediate this process. The enhanced AMPAR- and NMDAR-mediated transmission markedly reduce the induction threshold of "Hebbian" LTP. We conclude that both modes of glutamatergic synaptic potentiation may play a critical functional role in the regulation of the learning machinery of the brain by adding flexibility to the demands of the hippocampal network.
Collapse
|
190
|
Numakawa T, Yokomaku D, Richards M, Hori H, Adachi N, Kunugi H. Functional interactions between steroid hormones and neurotrophin BDNF. World J Biol Chem 2010; 1:133-43. [PMID: 21540998 PMCID: PMC3083963 DOI: 10.4331/wjbc.v1.i5.133] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 05/20/2010] [Accepted: 05/24/2010] [Indexed: 02/05/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF), a critical neurotrophin, regulates many neuronal aspects including cell differentiation, cell survival, neurotransmission, and synaptic plasticity in the central nervous system (CNS). Though BDNF has two types of receptors, high affinity tropomyosin-related kinase (Trk)B and low affinity p75 receptors, BDNF positively exerts its biological effects on neurons via activation of TrkB and of resultant intracellular signaling cascades including mitogen-activated protein kinase/extracellular signal-regulated protein kinase, phospholipase Cγ, and phosphoinositide 3-kinase pathways. Notably, it is possible that alteration in the expression and/or function of BDNF in the CNS is involved in the pathophysiology of various brain diseases such as stroke, Parkinson’s disease, Alzheimer’s disease, and mental disorders. On the other hand, glucocorticoids, stress-induced steroid hormones, also putatively contribute to the pathophysiology of depression. Interestingly, in addition to the reduction in BDNF levels due to increased glucocorticoid exposure, current reports demonstrate possible interactions between glucocorticoids and BDNF-mediated neuronal functions. Other steroid hormones, such as estrogen, are involved in not only sexual differentiation in the brain, but also numerous neuronal events including cell survival and synaptic plasticity. Furthermore, it is well known that estrogen plays a role in the pathophysiology of Parkinson’s disease, Alzheimer’s disease, and mental illness, while serving to regulate BDNF expression and/or function. Here, we present a broad overview of the current knowledge concerning the association between BDNF expression/function and steroid hormones (glucocorticoids and estrogen).
Collapse
Affiliation(s)
- Tadahiro Numakawa
- Tadahiro Numakawa, Misty Richards, Hiroaki Hori, Naoki Adachi, Hiroshi Kunugi, Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, 187-8502, Japan
| | | | | | | | | | | |
Collapse
|
191
|
Bender RA, Zhou L, Wilkars W, Fester L, Lanowski JS, Paysen D, Konig A, Rune GM. Roles of 17 -Estradiol Involve Regulation of Reelin Expression and Synaptogenesis in the Dentate Gyrus. Cereb Cortex 2010; 20:2985-95. [DOI: 10.1093/cercor/bhq047] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
|
192
|
Strom JO, Theodorsson E, Holm L, Theodorsson A. Different methods for administering 17beta-estradiol to ovariectomized rats result in opposite effects on ischemic brain damage. BMC Neurosci 2010; 11:39. [PMID: 20236508 PMCID: PMC2848231 DOI: 10.1186/1471-2202-11-39] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Accepted: 03/17/2010] [Indexed: 01/26/2023] Open
Abstract
Background Numerous stroke studies have controversially shown estrogens to be either neuroprotective or neurodamaging. The discordant results observed in rat brain ischemia models may be a consequence of discrepancies in estrogen administration modes resulting in plasma concentration profiles far from those intended. To test this hypothesis we reproduced in detail and extended an earlier study from our lab using a different mode of 17β-estradiol administration; home-made silastic capsules instead of commercial slow-release 17β-estradiol pellets. Four groups of female rats (n = 12) were ovariectomized and administered 17β-estradiol or placebo via silastic capsules. All animals underwent MCAo fourteen days after ovariectomy and were sacrificed three days later. Results In contrast to our earlier results using the commercial pellets, the group receiving 17β-estradiol during the entire experiment had significantly smaller lesions than the group receiving placebo (mean ± SEM: 3.85 ± 0.70% versus 7.15 ± 0.27% of total slice area, respectively; p = 0.015). No significant neuroprotection was found when the 17β-estradiol was administered only during the two weeks before or the three days immediately after MCAo. Conclusions The results indicate that different estrogen treatment regimens result in diametrically different effects on cerebral ischemia. Thus the effects of estrogens on ischemic damage seem to be concentration-related, with a biphasic, or even more complex, dose-response relation. These findings have implications for the design of animal experiments and also have a bearing on the estrogen doses used for peri-menopausal hormone replacement therapy.
Collapse
Affiliation(s)
- Jakob O Strom
- Institution of Clinical and Experimental Medicine/Department of Clinical Chemistry, Linkoping University, Linkoping, Sweden
| | | | | | | |
Collapse
|
193
|
Pleil KE, Williams CL. The development and stability of estrogen-modulated spatial navigation strategies in female rats. Horm Behav 2010; 57:360-7. [PMID: 20079739 PMCID: PMC2834838 DOI: 10.1016/j.yhbeh.2010.01.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 01/06/2010] [Accepted: 01/10/2010] [Indexed: 11/21/2022]
Abstract
Adult female rats with high levels of circulating estradiol are biased to use a place strategy to solve an ambiguous spatial navigation task and those with low levels are biased to use a response strategy. We examined the development of this hormonal modulation of strategy use by training juvenile female rats on an ambiguous navigation task and probing them for strategy use at postnatal day (PD) 16, 21, or 26, after administration of 17 beta-estradiol or oil 48 and 24 h prior to testing. We found that rats could use either strategy successfully by PD21 but that estradiol did not bias rats to use a place strategy until PD26. In order to evaluate the stability of this effect over multiple navigation experiences, we retested oil-treated juveniles three times during adulthood. On the first adult navigation experience, rats were significantly more likely to use the same navigation strategy they used as juveniles, regardless of current estrous cycle phase. On the second and third adult tests, after rats had more experience with the task, previous navigation experience did not predict strategy use. Rats in proestrus were significantly more likely to use a place strategy while rats in estrus and diestrus did not appear to have a group bias to use either strategy. These results suggest that estradiol can modulate spatial navigation strategy use before puberty but that this effect interacts with previous navigation experience. This study sheds light on when and under what circumstances estradiol gains control over spatial navigation behavior in the female rat.
Collapse
Affiliation(s)
- Kristen E Pleil
- Department of Psychology & Neuroscience, Duke University, Durham, NC 27708, USA
| | | |
Collapse
|
194
|
Zhou L, Fester L, von Blittersdorff B, Hassu B, Nogens H, Prange-Kiel J, Jarry H, Wegscheider K, Rune GM. Aromatase inhibitors induce spine synapse loss in the hippocampus of ovariectomized mice. Endocrinology 2010; 151:1153-60. [PMID: 20097718 DOI: 10.1210/en.2009-0254] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recently, inhibition of estrogen synthesis by aromatase inhibitors has become a favored therapy for breast cancer in postmenopausal women. Estrogen is, however, important for synapse formation in the hippocampus. Inhibition of aromatase induces spine synapse loss in organotypic hippocampal slice cultures. We therefore studied the effect of systemic treatment with the potent aromatase inhibitor letrozole on spine synapse formation and synaptic proteins in the hippocampi of female mice for periods of 7 d and 4 wk. In cyclic, letrozole-treated females and in ovariectomized, letrozole-treated females, the number of spine synapses was significantly reduced in the hippocampus but not in the prefrontal or cerebellar cortex. Consequently, the expression of the N-methyl-D-aspartate receptor NR1 was significantly down-regulated after treatment with letrozole. In cyclic animals the expression of the synaptic proteins synaptophysin and spinophilin was down-regulated in response to letrozole. In ovariectomized animals, however, protein expression was down-regulated after 7 d of treatment, whereas the expression was up-regulated after 4 wk of treatment. Our results indicate that systemic inhibition of aromatase in mice affects structural synaptic plasticity in the hippocampus. This may contribute to cognitive deficits in postmenopausal women treated with aromatase inhibitors.
Collapse
Affiliation(s)
- Lepu Zhou
- Institute of Anatomy I, Cellular Neurobiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
195
|
Prange-Kiel J, Fester L, Zhou L, Jarry H, Rune GM. Estrus cyclicity of spinogenesis: underlying mechanisms. J Neural Transm (Vienna) 2010; 116:1417-25. [PMID: 19730783 PMCID: PMC3085745 DOI: 10.1007/s00702-009-0294-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 08/06/2009] [Indexed: 11/09/2022]
Abstract
Hippocampal spine density varies with the estrus cycle. The cyclic change in estradiol levels in serum was hypothesized to underlie this phenomenon, since treatment of ovariectomized animals with estradiol induced an increase in spine density in hippocampal dendrites of rats, as compared to ovariectomized controls. In contrast, application of estradiol to hippocampal slice cultures did not promote spinogenesis. In addressing this discrepancy, we found that hippocampal neurons themselves are capable of synthesizing estradiol de novo. Estradiol synthesis can be suppressed by aromatase inhibitors and by knock-down of Steroid Acute Regulatory Protein (StAR) and enhanced by substrates of steroidogenesis. Expression of estrogen receptors (ERs) and synaptic proteins, synaptogenesis, and long-term potentiation (LTP) correlated positively with aromatase activity in hippocampal cultures without any difference between genders. All effects due to inhibition of aromatase activity were rescued by application of estradiol to the cultures. Most importantly, gonadotropin-releasing hormone (GnRH) increased estradiol synthesis dose-dependently via an aromatase-mediated mechanism and consistently increased spine synapse density and spinophilin expression. As a consequence, our data suggest that cyclic fluctuations in spine synapse density result from pulsative release of GnRH from the hypothalamus and its effect on hippocampal estradiol synthesis, rather than from varying levels of serum estradiol. This hypothesis is further supported by higher GnRH receptor (GnRH-R) density in the hippocampus than in the cortex and hypothalamus and the specificity of estrus cyclicity of spinogenesis in the hippocampus, as compared to the cortex.
Collapse
Affiliation(s)
- Janine Prange-Kiel
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | | | | | | | | |
Collapse
|
196
|
Riedemann T, Patchev AV, Cho K, Almeida OFX. Corticosteroids: way upstream. Mol Brain 2010; 3:2. [PMID: 20180948 PMCID: PMC2841592 DOI: 10.1186/1756-6606-3-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 01/11/2010] [Indexed: 01/20/2023] Open
Abstract
Studies into the mechanisms of corticosteroid action continue to be a rich bed of research, spanning the fields of neuroscience and endocrinology through to immunology and metabolism. However, the vast literature generated, in particular with respect to corticosteroid actions in the brain, tends to be contentious, with some aspects suffering from loose definitions, poorly-defined models, and appropriate dissection kits. Here, rather than presenting a comprehensive review of the subject, we aim to present a critique of key concepts that have emerged over the years so as to stimulate new thoughts in the field by identifying apparent shortcomings. This article will draw on experience and knowledge derived from studies of the neural actions of other steroid hormones, in particular estrogens, not only because there are many parallels but also because 'learning from differences' can be a fruitful approach. The core purpose of this review is to consider the mechanisms through which corticosteroids might act rapidly to alter neural signaling.
Collapse
Affiliation(s)
- Therese Riedemann
- Max-Planck-Institute of Psychiatry, Kraepelin Str. 2-10, 80804 Munich, Germany
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Faculty of Medicine and Dentistry, University of Bristol, Bristol, UK
| | - Alexandre V Patchev
- Max-Planck-Institute of Psychiatry, Kraepelin Str. 2-10, 80804 Munich, Germany
| | - Kwangwook Cho
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Faculty of Medicine and Dentistry, University of Bristol, Bristol, UK
| | - Osborne FX Almeida
- Max-Planck-Institute of Psychiatry, Kraepelin Str. 2-10, 80804 Munich, Germany
| |
Collapse
|
197
|
Wójtowicz T, Mozrzymas JW. Estradiol and GABAergic transmission in the hippocampus. VITAMINS AND HORMONES 2010; 82:279-300. [PMID: 20472144 DOI: 10.1016/s0083-6729(10)82015-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Estradiol is synthesized in the hippocampus and is known to increase intrinsic hippocampal excitability and capacity for synaptic plasticity. A picture emerges that at least part of these effects are due to a complex modulation of GABAergic system in developing and adult hippocampus. During development, GABAergic system undergoes profound alterations and is particularly prone to modulation. During this period, estradiol could modulate both phasic and tonic GABAergic currents and promote excitatory GABA actions. In contrast, in adult hippocampus, estradiol-induced formation of new dendritic spines in pyramidal cells is paralleled with a reduction in GABAergic drive to these neurons. Such estradiol actions could be mediated primarily through interneurons expressing estrogen receptors. In this chapter, we provide an overview of the in vitro and in vivo studies addressing the role of estradiol in regulating the GABAergic system in the hippocampal formation during development and in the adulthood. Although the mechanisms underlying such a regulation remain largely unknown, we make an attempt to present the major hypotheses and concepts related to this issue.
Collapse
Affiliation(s)
- Tomasz Wójtowicz
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, Wroclaw, Poland
| | | |
Collapse
|
198
|
Regulation of hippocampal synaptic plasticity by estrogen and progesterone. VITAMINS AND HORMONES 2010; 82:219-39. [PMID: 20472141 DOI: 10.1016/s0083-6729(10)82012-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Accumulating evidence indicates that the ovarian steroid hormones estrogen and progesterone regulate a wide variety of nonreproductive functions in the central nervous system by interacting with several molecular and cellular processes. A growing literature reporting results obtained in rodent models suggests that 17beta-estradiol, the most potent of the biologically relevant estrogens, facilitates some forms of learning and memory, and in particular, those involving hippocampus-dependent tasks. Hippocampal long-term potentiation and long-term depression of synaptic transmission are types of synaptic plasticity that have been extensively studied, as they are considered as cellular models of memory formation in the brain. In this chapter, we review the literature that analyzes and compares the effects of estrogen and progesterone on synaptic transmission and synaptic plasticity in rodents. Understanding the nonreproductive functions of estrogen and progesterone in the hippocampus has far-reaching implications not only for our basic understanding of neuroendocrinology and neurobiology, but also for developing better treatment of age-related diseases such as Alzheimer's disease.
Collapse
|
199
|
Zadran S, Qin Q, Bi X, Zadran H, Kim Y, Foy MR, Thompson R, Baudry M. 17-Beta-estradiol increases neuronal excitability through MAP kinase-induced calpain activation. Proc Natl Acad Sci U S A 2009; 106:21936-41. [PMID: 19995977 PMCID: PMC2799831 DOI: 10.1073/pnas.0912558106] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Indexed: 01/11/2023] Open
Abstract
17-Beta-estradiol (E2) is a steroid hormone involved in numerous brain functions. E2 regulates synaptic plasticity in part by enhancing NMDA receptor function and spine density in the hippocampus, resulting in increased long-term potentiation and facilitation of learning and memory. As the calcium-dependent neutral protease, calpain, is also involved in these processes, we tested whether E2 could activate calpain and examined the functional consequences of E2-mediated calpain activation in hippocampus. Calpain activity was analyzed by a fluorescence resonance energy transfer (FRET)-based assay that allows both quantitative determination and spatial resolution. E2 rapidly activated calpain in cultured cortical and hippocampal neurons, prominently in dendrites and dendritic spines. E2-induced calpain activation was mediated through mitogen-activated protein kinase (MAPK), as it was completely blocked by MEK inhibitors. It was also calcium-independent, as it was still evident in presence of the calcium chelator, BAPTA-AM. Activation of ERalpha and ERbeta receptors by specific agonists stimulated calpain activity. Finally, the rapid E2-mediated increase in excitability in acute hippocampal slices was prevented by a membrane-permeable calpain inhibitor. Furthermore, E2 treatment of acute hippocampal slices resulted in increased actin polymerization and membrane levels of GluR1 but not GluR2/3 subunits of AMPA receptors; both effects were also blocked by a calpain inhibitor. Our results indicate that E2 rapidly stimulates calpain activity through MAP kinase-mediated phosphorylation, resulting in increased membrane levels of AMPA receptors. These effects could be responsible for E2-mediated increase in neuronal excitability and facilitation of cognitive processes.
Collapse
Affiliation(s)
- Sohila Zadran
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089-2520; and
| | - Qingyu Qin
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766
| | - Xiaoning Bi
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766
| | - Homera Zadran
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089-2520; and
| | - Young Kim
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089-2520; and
| | - Michael R. Foy
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089-2520; and
| | - Richard Thompson
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089-2520; and
| | - Michel Baudry
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089-2520; and
| |
Collapse
|
200
|
Abstract
Evidence exists for the potential protective effects of circulating ovarian hormones in stroke, and oestrogen reduces brain damage in animal ischaemia models. However, a recent clinical trial indicated that HRT (hormone-replacement therapy) increased the incidence of stroke in post-menopausal women, and detrimental effects of oestrogen on stroke outcome have been identified in a meta-analysis of HRT trials and in pre-clinical research studies. Therefore oestrogen is not an agent that can be promoted as a potential stroke therapy. Many published reviews have reported the neuroprotective effects of oestrogen in stroke, but have failed to include information on the detrimental effects. This issue is addressed in the present review, along with potential mechanisms of action, and the translational capacity of pre-clinical research.
Collapse
|