101
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Green AD, Galea LAM. Adult hippocampal cell proliferation is suppressed with estrogen withdrawal after a hormone-simulated pregnancy. Horm Behav 2008; 54:203-11. [PMID: 18423635 DOI: 10.1016/j.yhbeh.2008.02.023] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 02/15/2008] [Accepted: 02/22/2008] [Indexed: 11/28/2022]
Abstract
Estradiol withdrawal after pregnancy is hypothesized to precipitate depressive symptoms in vulnerable women. A hormone-simulated pregnancy was induced in female rats and the effects of a 'postpartum' drop in estradiol on hippocampal cell proliferation were examined. All groups were ovariectomized or given sham surgery prior to treatment. Rats were randomly assigned to 'postpartum', 'postpartum'+EB (estradiol benzoate), 'postpartum'+DPN (diarylpropionitrile; an ERbeta agonist), 'postpartum'+IMI (imipramine; a tricyclic antidepressant), sham, ovariectomized (OVX), sham+IMI or OVX+IMI groups. All 'postpartum' groups received hormone injections (estradiol and progesterone) over 23 days to simulate pregnancy, while IMI groups also received daily imipramine injections. After day 23, 'postpartum' rats were withdrawn from the hormone-simulated pregnancy (mimicking the postpartum drop in gonadal hormones), while other 'postpartum' treatment groups received daily injections of DPN, EB or IMI. On day 3 'postpartum' all rats were injected with bromodeoxyuridine (BrdU; a DNA synthesis marker) and perfused 24 h later to assess cell proliferation and cell death in the dentate gyrus. 'Postpartum' hormone withdrawal decreased hippocampal cell proliferation in the 'postpartum' and 'postpartum'+EB groups only. Chronic imipramine significantly increased hippocampal cell proliferation in sham+IMI, but not OVX+IMI rats suggesting that imipramine's effects to increase hippocampal cell proliferation in female rats is related to reproductive status. Cell death (pyknotic cells) was decreased only in the 'postpartum' group. Together, these results suggest an important, though complex, role for gonadal hormones in the cellular changes accompanying this model of postpartum depression.
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Affiliation(s)
- Amanda D Green
- Department of Psychology and Brain Research Centre, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada
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102
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Spencer JL, Waters EM, Romeo RD, Wood GE, Milner TA, McEwen BS. Uncovering the mechanisms of estrogen effects on hippocampal function. Front Neuroendocrinol 2008; 29:219-37. [PMID: 18078984 PMCID: PMC2440702 DOI: 10.1016/j.yfrne.2007.08.006] [Citation(s) in RCA: 308] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 08/14/2007] [Indexed: 01/06/2023]
Abstract
Estrogens have direct effects on the brain areas controlling cognition. One of the most studied of these regions is the dorsal hippocampal formation, which governs the formation of spatial and episodic memories. In laboratory animals, most investigators report that estrogen enhances synaptic plasticity and improves performance on hippocampal-dependent cognitive behaviors. This review summarizes work conducted in our laboratory and others toward identifying estrogen's actions in the hippocampal formation, and the mechanisms for these actions. Physiologic and pharmacologic estrogen affects cognitive behavior in mammals, which may be applicable to human health and disease. The effects of estrogen in the hippocampal formation that lead to modulation of hippocampal function include effects on cell morphology, synapse formation, signaling, and excitability that have been studied in laboratory mice, rats, and primates. Finally, estrogen may signal through both nuclear and extranuclear hippocampal estrogen receptors to achieve its downstream effects.
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Affiliation(s)
- Joanna L Spencer
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, 1300 York Avenue, New York, NY 10065, USA
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103
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Tauber SC, Bunkowski S, Schlumbohm C, Rühlmann M, Fuchs E, Nau R, Gerber J. No long-term effect two years after intrauterine exposure to dexamethasone on dentate gyrus volume, neuronal proliferation and differentiation in common marmoset monkeys. Brain Pathol 2008; 18:497-503. [PMID: 18422980 DOI: 10.1111/j.1750-3639.2008.00149.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Glucocorticoids are prenatally administered to promote the maturation of the lungs. They, however, can affect neuronal proliferation and differentiation. In newborn marmoset monkeys, intrauterine hyperexposure to dexamethasone (DEX) resulted in a significantly decreased proliferation rate in the hippocampal dentate gyrus without affecting neuronal differentiation. In this study, marmoset monkeys received 5 mg/kg body weight DEX either during early (days 42-48) or late (days 90-96) pregnancy. The volume of the dentate granule cell layer as well as the proliferation and neuronal differentiation in the dentate gyrus of their 2-year-old offspring were investigated. The density of proliferating cells (Ki-67), apoptotic cells (in situ tailing) and cells differentiating to neurons (double cortin, TUC-4 and calretinin) were determined immunohistochemically. Analysis of the dentate granule cell layer volume showed no significant differences between early or late DEX-exposed marmosets and untreated control animals. Similarly, proliferation and neuronal differentiation in DEX-treated animals was not significantly different in comparison with controls. In summary, the decreased proliferation rate observed in newborn marmosets after intrauterine exposure to DEX was no longer detectable in their 2-year-old siblings suggesting no long-lasting effect of prenatal hyperexposure to DEX on neuronal proliferation and differentiation in the dentate gyrus of marmoset monkeys.
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Affiliation(s)
- Simone C Tauber
- Department of Neurology, Georg-August-University, Göttingen, Germany
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104
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Calingasan NY, Ho DJ, Wille EJ, Campagna MV, Ruan J, Dumont M, Yang L, Shi Q, Gibson GE, Beal MF. Influence of mitochondrial enzyme deficiency on adult neurogenesis in mouse models of neurodegenerative diseases. Neuroscience 2008; 153:986-96. [PMID: 18423880 DOI: 10.1016/j.neuroscience.2008.02.071] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 02/03/2008] [Accepted: 02/27/2008] [Indexed: 02/04/2023]
Abstract
Mitochondrial defects including reduction of a key mitochondrial tricarboxylic acid cycle enzyme alpha-ketoglutarate-dehydrogenase complex (KGDHC) are characteristic of many neurodegenerative diseases. KGDHC consists of alpha-ketoglutarate dehydrogenase, dihydrolipoyl succinyltransferase (E2k), and dihydrolipoamide dehydrogenase (Dld) subunits. We investigated whether Dld or E2k deficiency influences adult brain neurogenesis using immunohistochemistry for the immature neuron markers, doublecortin (Dcx) and polysialic acid-neural cell adhesion molecule, as well as a marker for proliferation, proliferating cell nuclear antigen (PCNA). Both Dld- and E2k-deficient mice showed reduced Dcx-positive neuroblasts in the subgranular zone (SGZ) of the hippocampal dentate gyrus compared with wild-type mice. In the E2k knockout mice, increased immunoreactivity for the lipid peroxidation marker, malondialdehyde occurred in the SGZ. These alterations did not occur in the subventricular zone (SVZ). PCNA staining revealed decreased proliferation in the SGZ of E2k-deficient mice. In a transgenic mouse model of Alzheimer's disease, Dcx-positive cells in the SGZ were also reduced compared with wild type, but Dld deficiency did not exacerbate the reduction. In the malonate lesion model of Huntington's disease, Dld deficiency did not alter the lesion-induced increase and migration of Dcx-positive cells from the SVZ into the ipsilateral striatum. Thus, the KGDHC subunit deficiencies associated with elevated lipid peroxidation selectively reduced the number of neuroblasts and proliferating cells in the hippocampal neurogenic zone. However, these mitochondrial defects neither exacerbated certain pathological conditions, such as amyloid precursor protein (APP) mutation-induced reduction of SGZ neuroblasts, nor inhibited malonate-induced migration of SVZ neuroblasts. Our findings support the view that mitochondrial dysfunction can influence the number of neural progenitor cells in the hippocampus of adult mice.
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Affiliation(s)
- N Y Calingasan
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10065, USA.
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105
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Noonan MA, Choi KH, Self DW, Eisch AJ. Withdrawal from cocaine self-administration normalizes deficits in proliferation and enhances maturity of adult-generated hippocampal neurons. J Neurosci 2008; 28:2516-26. [PMID: 18322096 PMCID: PMC6671196 DOI: 10.1523/jneurosci.4661-07.2008] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 01/10/2008] [Accepted: 01/29/2008] [Indexed: 11/21/2022] Open
Abstract
Relapse, a major problem in the treatment of cocaine addiction, is proposed to result in part from neuroadaptations in the hippocampus. We examined how a mediator of hippocampal neuroplasticity, adult neurogenesis in the subgranular zone (SGZ), was regulated by cocaine self-administration (CSA), and whether these changes were reversed by 4 weeks of withdrawal (CSA-WD) versus continued cocaine self-administration (CSA-CONT). Rats self-administered intravenous cocaine or saline for 3 weeks and were killed 2 h (CSA) or 4 weeks (CSA-WD, CSA-CONT) after injection with the S-phase marker bromodeoxyuridine (BrdU). Cells in several stages of adult neurogenesis were quantified: proliferating cells labeled by BrdU (2 h) or Ki-67; immature neurons labeled by doublecortin; and adult-generated neurons labeled with BrdU (4 weeks) and the mature neuronal marker NeuN. CSA decreased proliferation in both the SGZ and the subventricular zone (SVZ), a source of adult-generated olfactory neurons, changes reversed by CSA-WD. Unexpectedly, CSA-WD and CSA-CONT resulted in more immature doublecortin-immunopositive (+) neurons in the posterior SGZ and a normal number of adult-generated BrdU+ neurons in the SGZ, suggesting an enduring impact of CSA regardless of whether cocaine intake was stopped or continued. However, only CSA-WD rats had more adult-generated neurons with punctate BrdU staining, an indicator of enhanced maturity. These data suggest a mechanism for the cognitive and olfactory deficits seen in cocaine addicts, and further suggest that adult-generated neurons should be considered for their potential role in cocaine addiction and hippocampal-mediated relapse after cocaine withdrawal.
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Affiliation(s)
- Michele A. Noonan
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9070, and
| | - Kwang H. Choi
- Stanley Laboratory of Brain Research, Rockville, Maryland 20850
| | - David W. Self
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9070, and
| | - Amelia J. Eisch
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9070, and
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106
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Galea LAM. Gonadal hormone modulation of neurogenesis in the dentate gyrus of adult male and female rodents. ACTA ACUST UNITED AC 2008; 57:332-41. [PMID: 17669502 DOI: 10.1016/j.brainresrev.2007.05.008] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Revised: 05/11/2007] [Accepted: 05/14/2007] [Indexed: 02/08/2023]
Abstract
Gonadal hormones modulate neurogenesis in the dentate gyrus differentially in male and female adult rodents. Neurogenesis is comprised of at least two components: cell proliferation (the production of new cells) and cell survival (the number of new neurons that survive to maturity). Previous studies have found sex differences in the level of cell proliferation in the dentate gyrus only when comparing females in a high estrogen state to males. This review focuses on the effects of acute and chronic levels of estrogens or androgens on hippocampal neurogenesis in the adult male and female rodent. Evidence is also reviewed for the co-localization of androgen receptors and estrogen receptors (ER) with markers for cell proliferation or immature new cell survival. Briefly, evidence suggests that acute estradiol initially enhances and subsequently suppresses cell proliferation in the dentate gyrus of adult female rodents but may have limited effects in male rodents. Both the two known ER subtypes, ERalpha and beta upregulate hippocampal neurogenesis via cell proliferation. Intriguingly, repeated exposure to estradiol modulates hippocampal neurogenesis and cell death in adult female, but not male, rodents. However short-term estradiol treatment (5 days) in male meadow voles enhances new cell survival in the dentate gyrus but only when administered during the 'axon extension' phase. Furthermore, evidence is also reviewed showing a difference in response to acute and chronic estradiol treatment in older female rats compared to younger female rats. Recent findings from our laboratory indicate that testosterone and dihydrotestosterone upregulate hippocampal neurogenesis (via cell survival), but not cell proliferation, in adult male rodents. Effects of endogenous fluctuations in gonadal hormones on adult neurogenesis are observed across the seasons in meadow voles and during pregnancy and lactation in the rat dam. Pregnancy and motherhood differentially regulate adult hippocampal neurogenesis in the adult female rodent, with primiparous rats displaying lower levels of hippocampal cell proliferation and survival after parturition. Few studies have compared males and females but existing research suggests a sex difference in the hormonal regulation of hippocampal neurogenesis in the adult. Clearly more work is needed to elucidate the effects of gonadal hormones on neurogenesis in the dentate gyrus of both male and female rodents across the lifespan, especially if we are to use our knowledge of how adult neurogenesis is regulated to develop strategies to repair neuron loss in neurodegenerative diseases.
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Affiliation(s)
- Liisa A M Galea
- Program in Neuroscience, Department of Psychology and Brain Research Centre, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada V6T 1Z4.
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107
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Repeated estradiol administration alters different aspects of neurogenesis and cell death in the hippocampus of female, but not male, rats. Neuroscience 2008; 152:888-902. [PMID: 18353559 DOI: 10.1016/j.neuroscience.2007.10.071] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 09/20/2007] [Accepted: 10/08/2007] [Indexed: 02/07/2023]
Abstract
Estradiol has been shown to have neuroprotective effects, and acute estradiol treatment enhances hippocampal neurogenesis in the female brain. However, little is known about the effects of repeated administration of estradiol on the female brain, or about the effects of estradiol on the male brain. Gonadectomized male and female adult rats were injected with 5-bromo-2-deoxyuridine (BrdU) (200 mg/kg), and then 24 h later were given subcutaneous injections of either estradiol benzoate (33 mug/kg) or vehicle daily for 15 days. On day 16, animals were perfused and the brains processed to examine cells expressing Ki-67 (cell proliferation), BrdU (cell survival), doublecortin (young neuron production), pyknotic morphology (cell death), activated caspase-3 (apoptosis), and Fluoro-Jade B (degenerating neurons) in the dentate gyrus. In female rats, repeated administration of estradiol decreased the survival of new neurons (independent of any effects on initial cell proliferation), slightly increased cell proliferation, and decreased overall cell death in the dentate gyrus. In male rats, repeated administration of estradiol had no significant effect on neurogenesis or cell death. We therefore demonstrate a clear sex difference in the response to estradiol of hippocampal neurogenesis and apoptosis in adult rats, with adult females being more responsive to the effects of estradiol than males.
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108
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Fischer SJ, Arguello AA, Charlton JJ, Fuller DC, Zachariou V, Eisch AJ. Morphine blood levels, dependence, and regulation of hippocampal subgranular zone proliferation rely on administration paradigm. Neuroscience 2007; 151:1217-24. [PMID: 18248906 DOI: 10.1016/j.neuroscience.2007.11.035] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Revised: 11/02/2007] [Accepted: 11/28/2007] [Indexed: 11/25/2022]
Abstract
Chronic morphine, administered via s.c. pellet, decreases the number of proliferating cells in the dentate gyrus subgranular zone (SGZ) in both rats and mice. This robust morphine-induced decrease could be used to better understand mechanisms regulating adult hippocampal neurogenesis, as well as to explore the relationship between neurogenesis and drug dependence, withdrawal, and relapse behaviors. Such research would benefit enormously from identifying a route of morphine administration that produces addiction-relevant blood levels of morphine, results in a high degree of dependence, translates to both rat and mouse, and is free of the behavioral confounds of s.c. pellets. Therefore, we examined a classic chronic morphine pellet paradigm (two s.c. pellets over 5 days) versus three chronic morphine injection paradigms (escalating dose i.p. injections over 2, 5, or 10 days) for their effect in adult male C57BL/6J mice. We assessed blood morphine levels, SGZ proliferation, and drug dependence as assessed by tolerance to locomotion sensitization and naloxone-precipitated withdrawal. The pellet paradigm produced high and relatively stable blood levels of morphine, a high degree of dependence, and a significant decrease in SGZ proliferation. In contrast, the three injection paradigms produced transient spikes in morphine blood levels, significantly less dependence than the pellet paradigm, and no significant decrease in SGZ proliferation. These data show that regulation of mouse SGZ proliferation requires high and relatively stable blood levels of morphine, and provide critical knowledge for the design of future studies to probe the relationship between addiction and neurogenesis.
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Affiliation(s)
- S J Fischer
- Department of Psychiatry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9070, USA
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109
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Decreased proliferation of hippocampal progenitor cells in APPswe/PS1dE9 transgenic mice. Neuroreport 2007; 18:1801-5. [DOI: 10.1097/wnr.0b013e3282f1c9e9] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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110
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Xiong Y, Mahmood A, Lu D, Qu C, Goussev A, Schallert T, Chopp M. Role of gender in outcome after traumatic brain injury and therapeutic effect of erythropoietin in mice. Brain Res 2007; 1185:301-12. [PMID: 17976541 DOI: 10.1016/j.brainres.2007.09.052] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 09/07/2007] [Accepted: 09/11/2007] [Indexed: 10/22/2022]
Abstract
The aim of this study was to investigate the role of gender in histological and functional outcome, angiogenesis, neurogenesis and therapeutic effects of recombinant human erythropoietin (rhEPO) in mice after traumatic brain injury (TBI). TBI caused both tissue loss in the cortex and cell loss in the dentate gyrus (DG) in the injured hemisphere at day 35 post TBI without a significant gender difference. After TBI, sensorimotor deficits were significantly larger in male mice compared to females, while similar spatial learning deficits were present in both genders. TBI alone significantly stimulated angiogenesis and neurogenesis in the cortex and in the DG of injured hemispheres in both genders. rhEPO at a dose of 5000 units/kg body weight administered intraperitoneally at 6 h, and 3 and 7 days after injury significantly reduced lesion volume and DG cell loss examined at day 35 after TBI as well as dramatically improved sensorimotor and spatial learning performance without an obvious gender proclivity. rhEPO significantly enhanced neurogenesis in the cortex and the DG of the ipsilateral hemisphere in male TBI mice. rhEPO did not affect angiogenesis in the ipsilateral cortex and DG in both genders after TBI. The present data demonstrate that posttraumatic administration of rhEPO improves histological and functional outcome in both genders, which may be mediated by reducing cortical tissue damage and DG cell loss in the ipsilateral hemisphere. In addition, the major gender propensity observed in the present study with mice after TBI without treatment is limited to sensorimotor deficits and cell proliferation.
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Affiliation(s)
- Ye Xiong
- Department of Neurosurgery, Henry Ford Health System, 2799 West Grand Boulevard, Detroit, MI 48202, USA
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