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Appleman ML, Thomas JL, Weiss AR, Nilaver BI, Cervera-Juanes R, Kohama SG, Urbanski HF. Effect of hormone replacement therapy on amyloid beta (Aβ) plaque density in the rhesus macaque amygdala. Front Aging Neurosci 2024; 15:1326747. [PMID: 38274989 PMCID: PMC10808750 DOI: 10.3389/fnagi.2023.1326747] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/27/2023] [Indexed: 01/27/2024] Open
Abstract
Background Amyloid beta (Aβ) plaque density was examined in the amygdala of rhesus macaques, to elucidate the influence of age, diet and hormonal environment. Methods Luminex technology was used to measure cerebrospinal fluid (CSF) concentrations of Aβ40 and Aβ42 across three decades, while immunohistochemistry was used to examine Aβ plaque density in the amygdala. Results Aβ40 was found to be the predominant isoform of Aβ in the CSF, but neither Aβ40 or Aβ42 concentrations showed an age-related change, and the ratio of Aβ42 to Aβ40 showed only a marginal increase. Significantly fewer Aβ plaques were detected in the amygdala of old ovariectomized animals if they received estradiol HRT (p < 0.001); similar results were obtained regardless of whether they had been maintained on a regular monkey chow for ∼48 months or on a high-fat, high-sugar, Western-style diet for ∼30 months. Conclusion The results demonstrate that HRT involving estrogen can reduce Aβ plaque load in a cognitive brain region of aged non-human primates. The results from this translational animal model may therefore have clinical relevance to the treatment of AD in post-menopausal women, whether used alone, or as a supplement to current pharmacological and monoclonal antibody-based interventions.
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Affiliation(s)
- Maria-Luisa Appleman
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Jeremy L. Thomas
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Alison R. Weiss
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Benjamin I. Nilaver
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Rita Cervera-Juanes
- Department of Physiology and Pharmacology, Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Steven G. Kohama
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Henryk F. Urbanski
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, United States
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR, United States
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States
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Shakya R, Amonruttanapun P, Limboonreung T, Chongthammakun S. 17β-estradiol mitigates the inhibition of SH-SY5Y cell differentiation through WNT1 expression. Cells Dev 2023; 176:203881. [PMID: 37914154 DOI: 10.1016/j.cdev.2023.203881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 10/01/2023] [Accepted: 10/27/2023] [Indexed: 11/03/2023]
Abstract
17β-estradiol (E2) and canonical WNT-signaling represent crucial regulatory pathways for microtubule dynamics and synaptic formation. However, it is unclear yet whether E2-induced canonical WNT ligands have significant impact on neurogenic repair under inflammatory condition. In this study, first, we prepared the chronic activated-microglial-conditioned media, known to be comprised of neuro-inflammatory components. Long term exposure of microglial conditioned media to SH-SY5Y cells showed a negative impact on differentiation markers, microtubule associated protein-2 (MAP2) and synaptophysin (SYP), which was successfully rescued by pre and co-treatment of 10 nM 17β-estradiol. The inhibition of estrogen receptors, ERα and ERβ significantly blocked the E2-mediated recovery in the expression of differentiation marker, SYP. Furthermore, the inflammatory inhibition of canonical signaling ligand, WNT1 was also found to be rescued by E2. To our surprise, E2 was unable to replicate this success with β-catenin, which is considered to be the intracellular transducer of canonical WNT signaling. However, WNT antagonist - Dkk1 blocked the E2-mediated recovery in the expression of the differentiation marker, MAP2. Therefore, our data suggests that E2-mediated recovery in SH-SY5Y differentiation follows a divergent pathway from the conventional canonical WNT signaling pathway, which seems to regulate microtubule stability without the involvement of β-catenin. This mechanism provides fresh insight into how estradiol contributes to the restoration of differentiation marker proteins in the context of chronic neuroinflammation.
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Affiliation(s)
- Rubina Shakya
- Department of Anatomy and Center for Neuroscience Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Department of Anatomy, Kathmandu University, School of Medical Sciences, Dhulikhel, Kavre 11008, Nepal.
| | - Prateep Amonruttanapun
- Chulabhorn International College of Medicine, Thammasat University, Rangsit Campus, Pathumthani 12121, Thailand.
| | - Tanapol Limboonreung
- Department of Oral Biology, Faculty of Dentistry, King Mongkut's Institute of Technology Ladkrabang, Ladkrabang, Bangkok 10520, Thailand.
| | - Sukumal Chongthammakun
- Department of Anatomy and Center for Neuroscience Faculty of Science, Mahidol University, Bangkok 10400, Thailand
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Wang FG, Sun Y, Cao J, Shen XR, Liu FW, Song SS, Hou XQ, Yin L. Effects of Danggui-Shaoyao-San on central neuroendocrine and pharmacokinetics in female ovariectomized rats. JOURNAL OF ETHNOPHARMACOLOGY 2023:116609. [PMID: 37150422 DOI: 10.1016/j.jep.2023.116609] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/09/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The traditional Chinese medicine formula Danggui-Shaoyao-San (DSS) has been reported to have estrogen-like effects and therapeutic effects on the symptoms of Alzheimer's disease (AD). AIM OF THE STUDY To explore whether the central oxytocin and neuroendocrine system is involved in the modulating effects of DSS on the cognition and neuropsychiatric hebaviors in female AD rats, and to investigate the pharmacokinetics of paeoniflorin and ferulic acid in female AD rats with DSS treatment. MATERIAL AND METHODS DSS (1.2, 3.2, 8.6g/kg/day) was orally administered to ovariectomized (OVX) rats, and saline was orally administered to sham operation rats as control group. The Morris water maze test, novel object recognition test, and passive avoidance test were conducted for evaluation of learning and memory abilities, while elevated plus maze test and forced swim test were performed to assess anxiety- and depressive-like behaviors. ELISA kits were used to detect the levels of estrogen (E), estrogen receptor α (ERα), oxytocin (OT), oxytocin receptor (OTR), acetylcholine (Ach), acetylcholin esterase (AchE), and choline acetyl transferase (ChAT) in the cortex. The concentrations of Ach, glutamate (Glu), γ-aminobutyric acid (GABA), 5-hydroxytryptamine (5-HT), norepinephrine (NE) and dopamine (DA) in the hippocampus were assessed by HPLC-MS. The changes of neuronal morphology in the hippocampus were observed by Nissl staining. The pharmacokinetics of paeoniflorin and ferulic acid in OVX rats with DSS treatment were studied by HPLC. RESULTS In the Morris water maze test, novel object recognition test, and passive avoidance test, OVX rats showed cognitive impairment. In the elevated plus maze test and forced swim test, the anxiety- and depressive-like behaviors of OVX rats were significant as compared to the control group. Treatment of DSS significantly imporved the cognitive deficits, and ameliorated anxiety- and depressive-like behaviors of OVX rats. The expression of E, ERα, OT, OTR, AchE and ChAT in the cortex of model group were significantly decreased, and DSS significantly reversed these changes. The concentrations of Ach, Glu, GABA, 5-HT and NE in the hippocampus of OVX rats were significantly decreased, whereas DSS significantly increased the levels of Ach, Glu, GABA, 5-HT and NE. There was no significant difference in the concentration of DA in the hippocampus among groups. Degenerating neurons in the hippocampal CA3 region were observed in OVX rats, and the number of neurons was decreased. DSS treatment reduced the degenerating neurons, and incresed the number of neurons. The MRT (0 - ∞), AUC (0 - ∞), Cmax and t1/2z values of paeoniflorin, and the AUC 0-∞ and Cmax value of ferulic acid were higher in DSS-treated OVX rats than those in the DSS-treated control rats. CONCLUSIONS DSS improves the learning and memory ability, and attenuates anxiety- and depressive-like behaviors of OVX rats. The mechanism may be through increasing estrogen, reducing cholinergic damage, and modulating neurotransmitters. The increase in absorption and elimination time of paeoniflorin and ferulic acid in OVX rats may enhance the efficacy of DSS.
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Affiliation(s)
- Fu-Guang Wang
- Institute of Pharmacology, Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong, 271016, PR China
| | - Yi Sun
- Institute of Pharmacology, Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong, 271016, PR China
| | - Juan Cao
- Institute of Pharmacology, Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong, 271016, PR China
| | - Xu-Ri Shen
- Institute of Pharmacology, Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong, 271016, PR China
| | - Fu-Wang Liu
- Institute of Pharmacology, Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong, 271016, PR China
| | - Shuang-Shuang Song
- Institute of Pharmacology, Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong, 271016, PR China
| | - Xue-Qin Hou
- Institute of Pharmacology, Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong, 271016, PR China.
| | - Lei Yin
- The Second Affiliated Hospital of Shandong First Medical University, 271000, PR China.
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Conley AC, Albert KM, McDonald BC, Saykin AJ, Dumas JA, Newhouse PA. Estradiol treatment in young postmenopausal women with self-reported cognitive complaints: Effects on cholinergic-mediated cognitive performance. Hum Psychopharmacol 2022; 37:e2838. [PMID: 35212023 PMCID: PMC9399322 DOI: 10.1002/hup.2838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 02/02/2022] [Accepted: 02/07/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Older women are at increased risk of developing Alzheimer's disease compared to men. One proposed reason is that following menopause there is a decline in estrogens. Estrogens are important for cholinergic functioning and attenuate the impact of cholinergic antagonists on cognitive performance in postmenopausal women. Self-reported or subjective cognitive complaints in middle or older age may represent a harbinger of cognitive decline and those who endorse cognitive complaints appear more likely to develop future cognitive impairment. However, the response of individuals with cognitive complaints after menopause to estrogen and the relationship to cholinergic functioning has not been investigated. This study investigated the effect of estrogen treatment using 17β-estradiol on cognitive performance following anticholinergic blockade in postmenopausal women and the relationship of this interaction with the level of self-reported (subjective) postmenopausal cognitive complaints. METHODS Forty postmenopausal women (aged 50-60 years) completed a 3-month treatment regimen of either 1 mg oral estradiol or placebo. Participants then completed four challenge days in which they completed cognitive and behavioral tasks after one of four cholinergic antagonist drug conditions (oral mecamylamine (MECA), intravenous scopolamine, combined MECA and scopolamine, or PLC). RESULTS Compared to PLC, the estradiol treated group performed worse on attention tasks under cholinergic challenge including the choice reaction time task and the critical flicker fusion task. In addition, participants who endorsed greater cognitive complaints showed reduced performance on the N-back working memory task, regardless of whether they received estradiol treatment. CONCLUSIONS The findings of this study indicate that estradiol treatment was unable to mitigate anticholinergic blockade in postmenopausal women with subjective cognitive complaints, and worsened performance on attention tasks. Moreover, the present study suggests that greater levels of cognitive complaints following menopause may be associated with an underlying decline in cholinergic function that may manifest as an inability to compensate during working memory tasks.
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Affiliation(s)
- Alexander C. Conley
- Department of Psychiatry, Center for Cognitive Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Kimberly M. Albert
- Department of Psychiatry, Center for Cognitive Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Brenna C. McDonald
- Department of Radiology and Imaging Sciences, Center for Neuroimaging, Indiana University School of Medicine, Indianapolis, USA
| | - Andrew J. Saykin
- Department of Radiology and Imaging Sciences, Center for Neuroimaging, Indiana University School of Medicine, Indianapolis, USA
| | - Julie A. Dumas
- Department of Psychiatry, Clinical Neuroscience Research Unit, University of Vermont College of Medicine, Burlington, Vermont, USA
| | - Paul A. Newhouse
- Department of Psychiatry, Center for Cognitive Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA,Geriatric Research, Education, and Clinical Center, Veterans Affairs Tennessee Valley Health System, Nashville, Tennessee, USA
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Bortz J, Klatt KC, Wallace TC. Perspective: Estrogen and the Risk of Cognitive Decline: A Missing Choline(rgic) Link? Adv Nutr 2021; 13:S2161-8313(22)00068-0. [PMID: 34849527 PMCID: PMC8970832 DOI: 10.1093/advances/nmab145] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Factors that influence the risk of neurocognitive decline and Alzheimer's disease (AD) may provide insight into therapies for both disease treatment and prevention. While age is the most striking risk factor for AD, it is notable that the prevalence of AD is higher in women, representing two-thirds of cases. To explore potential underlying biological underpinnings of this observation, the intent of this article is to explore the interplay between cognitive aging and sex hormones, the cholinergic system, and novel hypotheses related to the essential nutrient, choline. Mechanistic evidence points toward estrogen's neuroprotective effects being strongly dependent on its interactions with the cholinergic system, a modulator of attentional functioning, learning, and memory. Estrogen has been shown to attenuate anticholinergic-induced impairments in verbal memory and normalize patterns of frontal and occipital cortex activation, resulting in a more "young adult" phenotype. However, similar to estrogen replacement's effect in cardiovascular diseases, its putative protective effects may be restricted to early postmenopausal women only, supportive of the "critical window hypothesis." Estrogen's impact on the cholinergic system may act both locally in the brain but also through peripheral tissues. Estrogen is critical for inducing endogenous choline synthesis via the phosphatidylethanolamine N-methyltransferase (PEMT) pathway of phosphatidylcholine (PC) synthesis. PEMT is dramatically induced in response to estrogen, producing not only a PC molecule and source of choline for the brain but also a key source of the long-chain omega-3 fatty acid, DHA. Herein, we highlight novel hypotheses related to hormone replacement therapy and nutrient metabolism aimed at directing future preclinical and clinical investigation.
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Vitek MP, Araujo JA, Fossel M, Greenberg BD, Howell GR, Rizzo SJS, Seyfried NT, Tenner AJ, Territo PR, Windisch M, Bain LJ, Ross A, Carrillo MC, Lamb BT, Edelmayer RM. Translational animal models for Alzheimer's disease: An Alzheimer's Association Business Consortium Think Tank. ALZHEIMER'S & DEMENTIA (NEW YORK, N. Y.) 2021; 6:e12114. [PMID: 33457489 PMCID: PMC7798310 DOI: 10.1002/trc2.12114] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/04/2020] [Accepted: 07/09/2020] [Indexed: 12/12/2022]
Abstract
Over 5 million Americans and 50 million individuals worldwide are living with Alzheimer's disease (AD). The progressive dementia associated with AD currently has no cure. Although clinical trials in patients are ultimately required to find safe and effective drugs, animal models of AD permit the integration of brain pathologies with learning and memory deficits that are the first step in developing these new drugs. The purpose of the Alzheimer's Association Business Consortium Think Tank meeting was to address the unmet need to improve the discovery and successful development of Alzheimer's therapies. We hypothesize that positive responses to new therapies observed in validated models of AD will provide predictive evidence for positive responses to these same therapies in AD patients. To achieve this goal, we convened a meeting of experts to explore the current state of AD animal models, identify knowledge gaps, and recommend actions for development of next-generation models with better predictability. Among our findings, we all recognize that models reflecting only single aspects of AD pathogenesis do not mimic AD. Models or combinations of new models are needed that incorporate genetics with environmental interactions, timing of disease development, heterogeneous mechanisms and pathways, comorbidities, and other pathologies that lead to AD and related dementias. Selection of the best models requires us to address the following: (1) which animal species, strains, and genetic backgrounds are most appropriate; (2) which models permit efficient use throughout the drug development pipeline; (3) the translatability of behavioral-cognitive assays from animals to patients; and (4) how to match potential AD therapeutics with particular models. Best practice guidelines to improve reproducibility also need to be developed for consistent use of these models in different research settings. To enhance translational predictability, we discuss a multi-model evaluation strategy to de-risk the successful transition of pre-clinical drug assets to the clinic.
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Affiliation(s)
| | | | | | | | | | | | - Nicholas T. Seyfried
- Departments of Biochemistry and NeurologyEmory School of MedicineAtlantaGeorgiaUSA
| | - Andrea J. Tenner
- Department of Molecular Biology and BiochemistryUniversity of CaliforniaIrvineCaliforniaUSA
| | | | | | - Lisa J. Bain
- Independent Science and Medical WriterElversonPennsylvaniaUSA
| | - April Ross
- Former Alzheimer's Association EmployeeChicagoIllinoisUSA
| | | | - Bruce T. Lamb
- Indiana University School of MedicineStark Neurosciences Research InstituteIndianapolisIndianaUSA
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7
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Xiao-Yao-San Formula Improves Cognitive Ability by Protecting the Hippocampal Neurons in Ovariectomized Rats. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:4156145. [PMID: 32655660 PMCID: PMC7321526 DOI: 10.1155/2020/4156145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 05/14/2020] [Accepted: 05/26/2020] [Indexed: 12/27/2022]
Abstract
Xiao-Yao-San (XYS) decoction is a traditional Chinese medicine formula. This study aimed to investigate the effect of XYS on cognitive abilities and its underlying mechanism in ovariectomized rats. Female Sprague-Dawley rats were ovariectomized and treated with XYS (3 g/kg or 9 g/kg) by gavage, with subcutaneous injection of 17-β estradiol (E2, 2 μg/kg) as a positive drug control and gavage of 1 ml saline (0.9%) as a placebo control. After 6 weeks of treatment, rats were examined using the Morris water maze test. The estradiol level in the serum and hippocampus was measured by ELISA. Golgi staining was performed to observe neuronal morphology in the hippocampus. Apoptosis of hippocampal cells was observed by TUNEL staining. The protein content of N-methyl-D-aspartate receptor (NMDAR) 2A and 2B in the hippocampal CA1 region was determined by Western blot and immunohistochemistry. Expression of estrogen receptor (ER) and PI3K signaling was detected by Western blot. Compared with the sham group, both learning and memory were impaired in ovariectomized rats. Rats treated with E2 or high-dose XYS showed better learning and memory compared with the saline-treated rats. High-dose XYS significantly reduced escape latency in the spatial acquisition trial; meanwhile, the cross times and duration in the probe quadrant were increased in the spatial probe trial. High-dose XYS promoted the de novo synthesis of E2 content in the hippocampus but had no significant effect on the serum E2 level. Golgi staining indicated that high-dose XYS could increase the branch number and density of dendritic spines in the hippocampal CA1 area. TUNEL staining showed that high-dose XYS alleviated ovariectomy-induced neuronal apoptosis. The expression level of NMDAR2A and NMDAR2B in hippocampal CA1 was upregulated by XYS treatment. The beneficial effect of XYS was through activating ERα-PI3K signaling. In conclusion, high-dose XYS treatment can improve the cognitive abilities of ovariectomized rats by protecting the hippocampal neurons and restoring the hippocampal E2 level.
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8
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Lu J, Wang X, Wan L, Fu J, Huo Y, Zhao Y, Guo C. Gene Polymorphisms Affecting the Pharmacokinetics and Pharmacodynamics of Donepezil Efficacy. Front Pharmacol 2020; 11:934. [PMID: 32636753 PMCID: PMC7317019 DOI: 10.3389/fphar.2020.00934] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 06/08/2020] [Indexed: 12/15/2022] Open
Abstract
Donepezil (DNP) is the first-line drug used for Alzheimer's disease (AD). However, the therapeutic response rate of patients to DNP varies from 20 to 60%. The main reason for the large differences in the clinical efficacy of DNP therapy is genetic factors, some of which affect pharmacokinetics (PK), while others affect pharmacodynamics (PD). Thus, much emphasis has been placed on the investigation of an association between PK- and PD-related gene polymorphisms and therapeutic response to DNP, but a consistent view does not yet exist. In this review, we summarize recent findings regarding genetic factors influencing the clinical efficacy of DNP, including substantial differences in individual responses as a consequence of polymorphisms in Cytochrome P450 (CYP) 2D6, CY3A4, CY3A5, APOE, ABCA1, ABCB1, ESR1, BCHE, PON-1, CHRNA7, and CHAT. We also discuss possible strategies for the evaluation of the clinical efficacy of DNP, with a specific focus on possible biomarkers of PK/PD parameters, and provide perspectives and limitations within the field, which will also be beneficial for understanding the multiple mechanisms of DNP therapy in AD.
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Affiliation(s)
- Jin Lu
- Department of Pharmacy, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Xiuzhe Wang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Lili Wan
- Department of Pharmacy, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Jianliang Fu
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Yan Huo
- Department of Pharmacy, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Yuwu Zhao
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Cheng Guo
- Department of Pharmacy, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.,School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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Abstract
The central cholinergic system is one of the most important modulator neurotransmitter system implicated in diverse behavioral processes. Activation of the basal forebrain cortical cholinergic input system represents a critical step in cortical information processing. This chapter explores recent developments illustrating cortical cholinergic transmission mediate defined cognitive operations, which is contrary to the traditional view that acetylcholine acts as a slowly acting neuromodulator that influences arousal cortex-wide. Specifically, we review the evidence that phasic cholinergic signaling in the prefrontal cortex is a causal mediator of signal detection. In addition, studies that support the neuromodulatory role of cholinergic inputs in top-down attentional control are summarized. Finally, we review new findings that reveal sex differences and hormonal regulation of the cholinergic-attention system.
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Affiliation(s)
- Vinay Parikh
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA, USA.
| | - Debra A Bangasser
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA, USA
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10
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De Loof A. Nature, Calcigender, Nurture: Sex-dependent differential Ca 2+ homeostasis as the undervalued third pillar. Commun Integr Biol 2019; 12:65-77. [PMID: 31143365 PMCID: PMC6527185 DOI: 10.1080/19420889.2019.1592419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 02/28/2019] [Accepted: 03/05/2019] [Indexed: 11/23/2022] Open
Abstract
After many years of sometimes heated discussions, the problem regarding the relative importance of two classical dogmas of the Nature (genes and sex-steroid hormones) versus Nurture (education, teaching-learning etc.) debate, is still awaiting a conclusive solution. Males and females differ in only a few (primordial) genes as is well documented by genomic analyses. However, their sex- and gender-specific behavior and physiology is nevertheless profoundly different, even if they grew up in a similar (educational) environment. By extending the “Calcigender-concept”, originally formulated in 2015, to the simplistic binary Nature versus Nurture concept, a novel framework showing that the sex-steroid hormone-dependent intracellular Calcium concentration is an important third factor may emerge. Although the principles of animal physiology and evolution strongly stress the fact that Nature is always dominant, Nurture can, to a limited extent, play a mitigating role.
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Affiliation(s)
- Arnold De Loof
- Functional Genomics and Proteomics Group, Department of Biology, KU Leuven-University of Leuven, Leuven, Belgium
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11
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Sex differences in stress reactivity in arousal and attention systems. Neuropsychopharmacology 2019; 44:129-139. [PMID: 30022063 PMCID: PMC6235989 DOI: 10.1038/s41386-018-0137-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/21/2018] [Accepted: 06/15/2018] [Indexed: 01/04/2023]
Abstract
Women are more likely than men to suffer from psychiatric disorders with hyperarousal symptoms, including posttraumatic stress disorder (PTSD) and major depression. In contrast, women are less likely than men to be diagnosed with schizophrenia and attention deficit hyperactivity disorder (ADHD), which share attentional impairments as a feature. Stressful events exacerbate symptoms of the aforementioned disorders. Thus, researchers are examining whether sex differences in stress responses bias women and men towards different psychopathology. Here we review the preclinical literature suggesting that, compared to males, females are more vulnerable to stress-induced hyperarousal, while they are more resilient to stress-induced attention deficits. Specifically described are sex differences in receptors for the stress neuropeptide, corticotropin-releasing factor (CRF), that render the locus coeruleus arousal system of females more vulnerable to stress and less adaptable to CRF hypersecretion, a condition found in patients with PTSD and depression. Studies on the protective effects of ovarian hormones against CRF-induced deficits in sustained attention are also detailed. Importantly, we highlight how comparing males and females in preclinical studies can lead to the development of novel therapeutics to improve treatments for psychiatric disorders in both women and men.
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Abstract
PURPOSE OF REVIEW Working memory (WM) is a key process that is integral to many complex cognitive tasks, and it declines significantly with advancing age. This review will survey recent evidence supporting the idea that the functioning of the WM system in women is modulated by circulating estrogens. RECENT FINDINGS In postmenopausal women, increased estrogen concentrations may be associated with improved WM function, which is evident on WM tasks that have a high cognitive load or significant manipulation demands. Experimental studies in rhesus monkeys and human neuroimaging studies support a prefrontal locus for these effects. Defining the basic neurochemical or cellular mechanisms that underlie the ability of estrogens to regulate WM is a topic of current research in both human and animal investigations. An emerging body of work suggests that frontal executive elements of the WM system are influenced by the circulating estrogen concentrations currently available to the CNS and that the effects are region-specific within the frontal cortex. These findings have implications for women's brain health and cognitive aging.
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Affiliation(s)
- Elizabeth Hampson
- Department of Psychology, Social Sciences Center, and Department of Psychiatry, University of Western Ontario, London, ON, N6A 5C2, Canada.
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13
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Hjelmervik H, Hausmann M, Craven AR, Hirnstein M, Hugdahl K, Specht K. Sex- and sex hormone-related variations in energy-metabolic frontal brain asymmetries: A magnetic resonance spectroscopy study. Neuroimage 2018; 172:817-825. [DOI: 10.1016/j.neuroimage.2018.01.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/22/2017] [Accepted: 01/17/2018] [Indexed: 12/26/2022] Open
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14
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Babaei P, Shirkouhi SG, Hosseini R, Soltani Tehrani B. Vitamin D is associated with metabotropic but not neurotrophic effects of exercise in ovariectomized rats. Diabetol Metab Syndr 2017; 9:91. [PMID: 29177013 PMCID: PMC5688735 DOI: 10.1186/s13098-017-0288-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 11/01/2017] [Indexed: 01/13/2023] Open
Abstract
PURPOSE Here, we studied the beneficial effects of aerobic exercise on metabolic syndrome components, cognitive performance, brain derived neurotrophic factor (BDNF) and irisin in ovariectomized rats with different serum vitamin D (Vit D) status. METHODS Eighty female wistar rats were divided into 2 groups of sham operated (sham, n = 8), and ovariectomized (OVX, n = 72). Then OVX were divided into 9 groups of receiving combination of exercise protocol with low dose of Vit D (OVX + EXE + LD), high dose of Vit D (OVX + EXE + HD), Vit D deficiency (OVX + EXE - D), and (OVX + EXE + Veh). Also non exercised groups of OVX receiving high dose of Vit D (OVX + HD), low dose of Vit D (OVX + LD), Vit D deficiency (OVX - D), and Veh (OVX + Veh) were included. After 2 months of related interventions, spatial memory was assessed using Morris water maze (MWM), and then metabolic syndrome components were measured. RESULTS High dose of Vit D supplementation showed significant reduction in weight (p = 0.001), lipid profiles (p = 0.001), visceral fat (p = 0.001) and waist circumference (p = 0.001) regardless of exercising or not, with no change in cognitiive function. Serum BDNF level was significantly higher in Vit D deficient group (p = 0.001), and was decreased in the OVX + HD. In contrary, irisin did not show any significant relationship with serum concentration of Vit D, while it was significantly elevated in the exercised groups compared with non-exercised counterparts. CONCLUSION Vit D insufficiency deteriorates metabolic syndrome components, and elevates serum BDNF as a compensatory metabotropic factor, and further supplementation significantly attenuates these components parallel with reduction in BDNF. In addition, aerobic exercise successfully induces various metabolic benefits, provided optimum serum level of Vit D.
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Affiliation(s)
- Parvin Babaei
- Cellular & Molecular Research Center, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, 2263 Iran
- Department of Physiology, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran
- Neuroscience Research Center, Guilan University of Medical Sciences, Rasht, Iran
| | - Samaneh Ghorbani Shirkouhi
- Cellular & Molecular Research Center, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, 2263 Iran
- Department of Physiology, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Rastegar Hosseini
- Department of Physical Education and Sport Sciences, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran
| | - Bahram Soltani Tehrani
- Cellular & Molecular Research Center, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, 2263 Iran
- Department of Pharmacology, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran
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15
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Sorwell KG, Renner L, Weiss AR, Neuringer M, Kohama SG, Urbanski HF. Cognition in aged rhesus monkeys: effect of DHEA and correlation with steroidogenic gene expression. GENES BRAIN AND BEHAVIOR 2016; 16:361-368. [PMID: 27736018 DOI: 10.1111/gbb.12351] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/15/2016] [Accepted: 10/09/2016] [Indexed: 11/29/2022]
Abstract
Estradiol supplementation has been shown to enhance cognitive performance in old ovariectomized rhesus macaques (Macaca mulatta). To determine if similar benefits could be achieved in perimenopausal animals using alternative hormonal supplements, we administered dehydroepiandrosterone (DHEA) to old ovary-intact female rhesus macaques for ∼2.5 months. Using computerized touch screen memory tasks, including delayed response (DR) and delayed matching-to-sample (DMS), we observed improved performance with time in all of the animals but failed to detect a significant effect of DHEA. On the other hand, gene expression profiling disclosed a significant correlation between cognitive performance and the expression of several steroidogenic and steroid-responsive genes. The DR performance was positively correlated with hippocampal expression of AKR1C3 and STAR and negatively correlated with the expression of SDRD5A1. A positive correlation was also found between DMS performance and prefrontal cortical expression of AKR1C3 and a negative correlation with STAR, as well as a negative correlation with the hippocampal expression of HSD11B1 and NR3C1. Taken together, the results suggest that steroidogenic gene regulation within the brain may help to maintain cognitive function during the perimenopausal transition period, despite a decline in sex-steroid levels in the circulation.
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Affiliation(s)
- K G Sorwell
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland
| | - L Renner
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton
| | - A R Weiss
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton.,Present address: Department of Psychology, Emory University, Atlanta, GA, USA
| | - M Neuringer
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton
| | - S G Kohama
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton
| | - H F Urbanski
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland.,Department of Physiology & Pharmacology, Oregon Health & Science University, Portland.,Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR, USA
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16
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Kohama SG, Renner L, Landauer N, Weiss AR, Urbanski HF, Park B, Voytko ML, Neuringer M. Effect of Ovarian Hormone Therapy on Cognition in the Aged Female Rhesus Macaque. J Neurosci 2016; 36:10416-10424. [PMID: 27707975 PMCID: PMC5050333 DOI: 10.1523/jneurosci.0909-16.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 07/14/2016] [Accepted: 08/20/2016] [Indexed: 01/18/2023] Open
Abstract
Studies of the effect of hormone therapy on cognitive function in menopausal women have been equivocal, in part due to differences in the type and timing of hormone treatment. Here we cognitively tested aged female rhesus macaques on (1) the delayed response task of spatial working memory, (2) a visuospatial attention task that measured spatially and temporally cued reaction times, and (3) a simple reaction time task as a control for motor speed. After task acquisition, animals were ovariectomized (OVX). Their performance was compared with intact controls for 2 months, at which time no group differences were found. The OVX animals were then assigned to treatment with either a subcutaneous sham implant (OVX), 17-β estradiol (E) implant (OVX+E) or E implant plus cyclic oral progesterone (OVX+EP). All groups were then tested repeatedly over 12 months. The OVX+E animals performed significantly better on the delayed response task than all of the other groups for much of the 12 month testing period. The OVX+EP animals also showed improved performance in the delayed response task, but only at 30 s delays and with performance levels below that of OVX+E animals. The OVX+E animals also performed significantly better in the visuospatial attention task, particularly in the most challenging invalid cue condition; this difference also was maintained across the 12 month testing period. Simple reaction time was not affected by hormonal manipulation. These data demonstrate that chronic, continuous administration of E can exert multiple beneficial cognitive effects in aged, OVX rhesus macaque females. SIGNIFICANCE STATEMENT Hormone therapy after menopause is controversial. We tested the effects of hormone replacement in aged rhesus macaques, soon after surgically-induced menopause [ovariectomy (OVX)], on tests of memory and attention. Untreated ovarian-intact and OVX animals were compared with OVX animals receiving estradiol (E) alone or E with progesterone (P). E was administered in a continuous fashion via subcutaneous implant, whereas P was administered orally in a cyclic fashion. On both tests, E-treated animals performed better than the other 3 experimental groups across 1 year of treatment. Thus, in this monkey model, chronic E administered soon after the loss of ovarian hormones had long-term benefits for cognitive function.
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Affiliation(s)
- Steven G Kohama
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon 97006-3448
| | - Lauren Renner
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon 97006-3448
| | - Noelle Landauer
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon 97006-3448
| | - Alison R Weiss
- Department of Psychology, Emory University, Atlanta, Georgia 30322
| | - Henryk F Urbanski
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon 97006-3448, Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon 97239-3098
| | - Byung Park
- School of Public Health, Oregon Health and Science University and Portland State University, Portland, Oregon 97239-3098, and
| | - Mary Lou Voytko
- Department of Neurobiology and Anatomy and the Interdisciplinary Program in Neuroscience, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1010
| | - Martha Neuringer
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon 97006-3448,
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Li C, Zhou C, Li R. Can Exercise Ameliorate Aromatase Inhibitor-Induced Cognitive Decline in Breast Cancer Patients? Mol Neurobiol 2016; 53:4238-4246. [PMID: 26223800 PMCID: PMC5651179 DOI: 10.1007/s12035-015-9341-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 07/07/2015] [Indexed: 12/14/2022]
Abstract
Aromatase inhibitors (AIs) have been commonly used as an effective adjuvant therapy in treatment of breast cancer, especially for menopausal women with estrogen receptor-positive breast cancer. Due to the nature of aromatase, the key enzyme for endogenous estrogen synthesis, inhibitory of aromatase-induced side effects, such as cognitive impairment has been reported in both human and animal studies. While extensive evidence suggested that physical exercises can improve learning and memory activity and even prevent age-related cognitive decline, basic research revealed some common pathways between exercise and estrogen signaling that affected cognitive function. This review draws on clinical and basic studies to assess the potential impact of exercise in cognitive function from women treated with AIs for breast cancer and explore the potential mechanism and effects of exercise on estrogen-related cognition.
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Affiliation(s)
- Cuicui Li
- Department of Sport Psychology, School of Sport Science, Shanghai University of Sport, Shanghai, 200438, China
| | - Chenglin Zhou
- Department of Sport Psychology, School of Sport Science, Shanghai University of Sport, Shanghai, 200438, China.
| | - Rena Li
- Department of Sport Psychology, School of Sport Science, Shanghai University of Sport, Shanghai, 200438, China.
- Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital and Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100012, China.
- Center for Hormone Advanced Science and Education, Roskamp Institute, Sarasota, FL, 34243, USA.
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18
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Newhouse P, Dumas J. Estrogen-cholinergic interactions: Implications for cognitive aging. Horm Behav 2015; 74:173-85. [PMID: 26187712 PMCID: PMC4573353 DOI: 10.1016/j.yhbeh.2015.06.022] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/02/2015] [Accepted: 06/23/2015] [Indexed: 12/31/2022]
Abstract
This article is part of a Special Issue "Estradiol and Cognition". While many studies in humans have investigated the effects of estrogen and hormone therapy on cognition, potential neurobiological correlates of these effects have been less well studied. An important site of action for estrogen in the brain is the cholinergic system. Several decades of research support the critical role of CNS cholinergic systems in cognition in humans, particularly in learning and memory formation and attention. In humans, the cholinergic system has been implicated in many aspects of cognition including the partitioning of attentional resources, working memory, inhibition of irrelevant information, and improved performance on effort-demanding tasks. Studies support the hypothesis that estradiol helps to maintain aspects of attention and verbal and visual memory. Such cognitive domains are exactly those modulated by cholinergic systems and extensive basic and preclinical work over the past several decades has clearly shown that basal forebrain cholinergic systems are dependent on estradiol support for adequate functioning. This paper will review recent human studies from our laboratories and others that have extended preclinical research examining estrogen-cholinergic interactions to humans. Studies examined include estradiol and cholinergic antagonist reversal studies in normal older women, examinations of the neural representations of estrogen-cholinergic interactions using functional brain imaging, and studies of the ability of selective estrogen receptor modulators such as tamoxifen to interact with cholinergic-mediated cognitive performance. We also discuss the implications of these studies for the underlying hypotheses of cholinergic-estrogen interactions and cognitive aging, and indications for prophylactic and therapeutic potential that may exploit these effects.
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Affiliation(s)
- Paul Newhouse
- Center for Cognitive Medicine, Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN, USA; Geriatric Research, Education, and Clinical Center, Veterans Affairs Tennessee Valley Health System, Nashville, TN, USA.
| | - Julie Dumas
- Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine, Burlington, VT, USA
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de Macêdo Medeiros A, Izídio GS, Sousa DS, Macedo PT, Silva AF, Shiramizu VKM, Cabral A, Ribeiro AM, Silva RH. Estrogen levels modify scopolamine-induced amnesia in gonadally intact rats. Prog Neuropsychopharmacol Biol Psychiatry 2014; 53:99-108. [PMID: 24657885 DOI: 10.1016/j.pnpbp.2014.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 02/24/2014] [Accepted: 03/10/2014] [Indexed: 12/23/2022]
Abstract
Previous studies suggested that estrogen plays a role in cognitive function by modulating the cholinergic transmission. However, most of the studies dealing with this subject have been conducted using ovariectomized rats. In the present study we evaluated the effects of physiological and supra-physiological variation of estrogen levels on scopolamine-induced amnesia in gonadally intact female rats. We used the plus-maze discriminative avoidance task (PMDAT) in order to evaluate anxiety levels and motor activity concomitantly to the memory performance. In experiment 1, female Wistar rats in each estrous cycle phase received scopolamine (1 mg/kg) or saline i.p. 20 min before the training session in the PMDAT. In experiment 2, rats in diestrus received estradiol valerate (1 mg/kg) or sesame oil i.m., and scopolamine (1 mg/kg) or saline i.p., 45 min and 20 min before the training, respectively. In experiment 3, rats in diestrus received scopolamine (1 mg/kg) or saline i.p. 20 min before the training, and estradiol valerate (1 mg/kg) or sesame oil i.m. immediately after the training session. In all experiments, a test session was performed 24 h later. The main results showed that: (1) scopolamine impaired retrieval and induced anxiolytic and hyperlocomotor effects in all experiments; (2) this cholinergic antagonist impaired acquisition only in animals in diestrus; (3) acute administration of estradiol valerate prevented the learning impairment induced by scopolamine and (4) interfered with memory consolidation process. The results suggest that endogenous variations in estrogen levels across the estrous cycle modulate some aspects of memory mediated by the cholinergic system. Indeed, specifically in diestrus, a stage with low estrogen levels, the impairment produced by scopolamine on the acquisition was counteracted by exogenous administration of the hormone, whereas the posttraining treatment potentiated the negative effects of scopolamine during the consolidation phase of memory.
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Affiliation(s)
| | - Geison Souza Izídio
- Behavioral Genetics Laboratory, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Diego Silveira Sousa
- Memory Studies Laboratory, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | | | | | | | - Alicia Cabral
- Memory Studies Laboratory, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | | | - Regina Helena Silva
- Memory Studies Laboratory, Universidade Federal do Rio Grande do Norte, Natal, Brazil.
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20
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Abstract
A variety of evidence suggests that, among humans, the individual tendency to choose immediate rewards ("Now") over larger, delayed rewards ("Later"), or Now bias, varies with frontal dopamine (DA) levels. As cyclic elevations in estradiol (E+) modulate other frontal DA-dependent behaviors, we tested ovarian cycle effects on Now bias, and whether any such effects are E+ mediated. To do so, we quantified Now/Later choice behavior in naturally cycling adult females (n = 87; ages 18-40 years) during both the menstrual phase (MP; cycle day 1-2; low E+), and the follicular phase (FP; cycle day 11-12; high E+). Now bias decreased an average of 3.6% from MP to FP (p = 0.006). Measures of salivary E+ levels at each visit were available in a subsample of participants (n = 34). Participants with a verified E+ rise from MP to FP showed significantly greater decreases in Now bias at mid-cycle (n = 23) than those without a rise (n = 11; p = 0.03); Now bias decreased an average of 10.2% in the E+ rise group but increased an average of 7.9% in the no E+ rise group. The change in Now bias from MP to FP inversely correlated with the change in E+ (ρ = -0.39; p = 0.023), an effect driven by individuals with putatively lower frontal DA based on genotype at the Val(158)Met polymorphism in the COMT gene. This is the first demonstration that intertemporal choice varies across the ovarian cycle, with Now bias declining at mid-cycle, when fertility peaks. Moreover, our data suggest that the interacting effects of estradiol and frontal DA mediate this cycle effect on decision making.
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21
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Scacchi R, Gambina G, Broggio E, Corbo RM. Sex and ESR1 genotype may influence the response to treatment with donepezil and rivastigmine in patients with Alzheimer's disease. Int J Geriatr Psychiatry 2014; 29:610-5. [PMID: 24150894 DOI: 10.1002/gps.4043] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 09/03/2013] [Accepted: 10/02/2013] [Indexed: 02/03/2023]
Abstract
BACKGROUND Many factors could be responsible for the different response to treatment with the cholinesterase inhibitors (ChEIs) donepezil and rivastigmine in Alzheimer's disease (AD) patients. Sex and the variants of the estrogen receptor α (ESR1) gene are reported to modulate AD susceptibility or the course of the disease. The aim of the present study was to verify whether patient's sex and ESR1 genotype could influence the response to ChEI treatment, as there is evidence that estrogens affect cholinergic system functioning. METHODS Two ESR1 intronic polymorphisms (PvuII, rs2234693; XbaI, rs9340799) were examined in 184 AD patients: 157 were receiving treatment with donepezil or rivastigmine and 27 were receiving no treatment. Cognitive status was assessed using the mini mental state examination at four time points (1, 3, 9, and 15 months into therapy). RESULTS Among the patients under treatment with either ChEI, the women responded more markedly than the men. As compared with the untreated patients, the effects of treatment were statistically significant for both donepezil and rivastigmine. A significant effect of ESR1 genotypes was observed for the donepezil-treated patients, among which those carrying at least one copy of P and X alleles showed a significantly lower cognitive decline than the noncarriers. CONCLUSIONS The present data seem to confirm a sex-related influence on treatment, as the women seemed to be more sensitive to therapy and to have experienced less cognitive decline. ESR1 may be another gene contributing to interindividual variability in response to treatment with ChEIs.
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Affiliation(s)
- Renato Scacchi
- CNR Institute of Molecular Biology and Pathology, c/o Department of Biology and Biotechnology, Sapienza University, Rome, Italy
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22
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Newhouse P, Albert K, Astur R, Johnson J, Naylor M, Dumas J. Tamoxifen improves cholinergically modulated cognitive performance in postmenopausal women. Neuropsychopharmacology 2013; 38:2632-43. [PMID: 23867982 PMCID: PMC3828534 DOI: 10.1038/npp.2013.172] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 06/25/2013] [Accepted: 07/02/2013] [Indexed: 12/15/2022]
Abstract
Tamoxifen (TMX) is a selective estrogen receptor modulator that is used as an estrogen receptor antagonist for the treatment and prevention of breast cancer. Whether TMX has antagonist activities in the human brain is less clear and its effects on cognitive function have not been experimentally explored. This study examined how TMX affected cognitive performance in older women using a model of anticholinergic drug-induced cognitive dysfunction. Twenty-one postmenopausal women were administered 20 mg of oral TMX or placebo for 3 months. Participants then took part in five drug challenges using the anticholinergic antinicotinic agent mecamylamine (MECA) and antimuscarinic agent scopolamine (SCOP) and were tested on a comprehensive battery including tasks of attention and psychomotor function, verbal episodic memory, and spatial navigation. After a 3-month placebo washout, participants were then crossed over to the alternate treatment and repeated the drug challenges after 3 months. Compared with placebo treatment, TMX significantly attenuated the impairment from cholinergic blockade on tasks of verbal episodic memory and spatial navigation, but effects on attentional/psychomotor tasks were more variable. Analysis by APOE genotype showed that APO ɛ4+ women showed a greater beneficial effect of TMX on reversing the cholinergic impairment than APO ɛ4- women on most tasks. This study provides evidence that TMX may act as an estrogen-like agonist to enhance cholinergic system activity and hippocampally mediated learning.
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Affiliation(s)
- Paul Newhouse
- Vanderbilt Center for Cognitive Medicine, Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN, USA,Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine, Burlington, VT, USA,Vanderbilt Center for Cognitive Medicine, Department of Psychiatry, Vanderbilt University School of Medicine, 1601 23rd Avenue, Nashville, TN 37212, USA, Tel: +1 615 936 0928, Fax: +1 615 875 0686, E-mail:
| | - Kimberly Albert
- Vanderbilt Center for Cognitive Medicine, Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Robert Astur
- Department of Psychology, University of Connecticut, Storrs, CT, USA
| | - Julia Johnson
- Department of Obstetrics and Gynecology, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Magdalena Naylor
- Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine, Burlington, VT, USA
| | - Julie Dumas
- Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine, Burlington, VT, USA
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Continuously delivered ovarian steroids do not alter dendritic spine density or morphology in macaque dorsolateral prefrontal cortical neurons. Neuroscience 2013; 255:219-25. [PMID: 24120552 DOI: 10.1016/j.neuroscience.2013.09.062] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 09/25/2013] [Accepted: 09/26/2013] [Indexed: 11/22/2022]
Abstract
Aged ovariectomized (OVX) female monkeys, a model for menopause in humans, show a decline in spine density in the dorsolateral prefrontal cortex (dlPFC) and diminished performance in cognitive tasks requiring this brain region. Previous studies in our laboratory have shown that long-term cyclic treatment with 17β-estradiol (E) produces an increase in spine density and in the proportion of thinner spines in layer III pyramidal neurons in the dlPFC of both young and aged OVX rhesus monkeys. Here we used 3D reconstruction of Lucifer yellow-loaded neurons to investigate whether clinically relevant schedules of hormone therapy would produce similar changes in prefrontal cortical neuronal morphology as long-term cyclic E treatment in young female monkeys. We found that continuously delivered E, with or without a cyclic progesterone treatment, did not alter spine density or morphology in the dlPFC of young adult OVX rhesus monkeys. We also found that the increased density of thinner spines evident in the dlPFC 24h after E administration in the context of long-term cyclic E therapy is no longer detectable 20days after E treatment. When compared with the results of our previously published investigations, our results suggest that cyclic fluctuations in serum E levels may cause corresponding fluctuations in the density of thin spines in the dlPFC. By contrast, continuous administration of E does not support sustained increases in thin spine density. Physiological fluctuations in E concentration may be necessary to maintain the morphological sensitivity of the dlPFC to E.
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Floody OR. Oxotremorine delays and scopolamine accelerates sexual exhaustion when applied to the preoptic area in male hamsters. Pharmacol Biochem Behav 2013; 110:75-88. [DOI: 10.1016/j.pbb.2013.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 06/06/2013] [Accepted: 06/13/2013] [Indexed: 11/28/2022]
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Smith YR, Bowen L, Love TM, Berent-Spillson A, Frey KA, Persad CC, Reame NK, Koeppe RA, Zubieta JK. Early initiation of hormone therapy in menopausal women is associated with increased hippocampal and posterior cingulate cholinergic activity. J Clin Endocrinol Metab 2011; 96:E1761-70. [PMID: 21865354 PMCID: PMC3205894 DOI: 10.1210/jc.2011-0351] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
CONTEXT The role of ovarian hormones in maintaining neuronal integrity and cognitive function is still debated. This study was undertaken to clarify the potential relationship between postmenopausal hormone use and the cholinergic system. OBJECTIVE We hypothesized that early initiated hormone therapy (HT) preserves the cholinergic system and that estrogen therapy (ET) would be associated with higher levels of acetylcholinesterase activity in the posterior cingulate cortex and hippocampus compared to estrogen plus progestin therapy (EPT) or no HT. DESIGN AND SETTING We conducted a cross-sectional study at a university teaching hospital. PATIENTS Fifty postmenopausal women (age, 65.2 ± 0.7 yr) with early long-term HT (n = 34; 13 ET and 21 EPT) or no HT (n = 16) participated in the study. INTERVENTIONS There were no interventions. MAIN OUTCOME MEASURE We measured cholinergic activity (acetylcholinesterase) in the hippocampus and posterior cingulate brain regions as measured by N-[(11)C]methylpiperidin-4-yl propionate and positron emission tomography as a marker of cholinergic function. RESULTS Significant effects of treatment on cholinergic activity measures were obtained in the left hippocampus (F = 3.56; P = 0.04), right hippocampus (F = 3.42; P = 0.04), and posterior cingulate (F = 3.76; P = 0.03). No significant effects were observed in a cortical control region. Post hoc testing identified greater cholinergic activity in the EPT group compared to the no-HT group in the left hippocampus (P = 0.048) and posterior cingulate (P = 0.045), with a nonstatistically significant trend in the right hippocampus (P = 0.073). CONCLUSIONS A differential effect of postmenopausal ET and EPT on cholinergic neuronal integrity was identified in postmenopausal women. The findings are consistent with a preservation of cholinergic neuronal integrity in the EPT group.
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Affiliation(s)
- Yolanda R Smith
- Department of Obstetrics and Gynecology, University of Michigan Health Systems, 1500 East Medical Center Drive, Room L4224 Women's Hospital, Ann Arbor, Michigan 48109-0276, USA.
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Haley GE, Kroenke C, Schwartz D, Kohama SG, Urbanski HF, Raber J. Hippocampal M1 receptor function associated with spatial learning and memory in aged female rhesus macaques. AGE (DORDRECHT, NETHERLANDS) 2011; 33:309-320. [PMID: 20890730 PMCID: PMC3168603 DOI: 10.1007/s11357-010-9184-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 09/03/2010] [Indexed: 05/29/2023]
Abstract
Of the acetylcholine muscarinic receptors, the type 1 (M1) and type 2 (M2) receptors are expressed at the highest levels in the prefrontal cortex (PFC) and hippocampus, brain regions important for cognition. As equivocal findings of age-related changes of M1 and M2 in the nonhuman primate brain have been reported, we first assessed age-related changes in M1 and M2 in the PFC and hippocampus using saturation binding assays. Maximum M1 receptor binding, but not affinity of M1 receptor binding, decreased with age. In contrast, the affinity of M2 receptor binding, but not maximum M2 receptor binding, increased with age. To determine if in the elderly cognitive performance is associated with M1 or M2 function, we assessed muscarinic function in elderly female rhesus macaques in vivo using a scopolamine challenge pharmacological magnetic resonance imaging and in vitro using saturation binding assays. Based on their performance in a spatial maze, the animals were classified as good spatial performers (GSP) or poor spatial performers (PSP). In the hippocampus, but not PFC, the GSP group showed a greater change in T(2)*-weighted signal intensity after scopolamine challenge than the PSP group. The maximum M1 receptor binding and receptor binding affinity was greater in the GSP than the PSP group, but no group difference was found in M2 receptor binding. Parameters of circadian activity positively correlated with the difference in T(2)*-weighted signal intensity before and after the challenge, the maximum M1 receptor binding, and the M1 receptor binding affinity. Thus, while in rhesus macaques, there are age-related decreases in M1 and M2 receptor binding, in aged females, hippocampal M1, but not M2, receptor function is associated with spatial learning and memory and circadian activity.
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Affiliation(s)
- Gwendolen E. Haley
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
| | - Chris Kroenke
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
| | - Daniel Schwartz
- Portland Veterans Administration Medical Center, Division of Psychiatry, Oregon Health and Science University, Portland, OR 97239 USA
| | - Steven G. Kohama
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
| | - Henryk F. Urbanski
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
| | - Jacob Raber
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006 USA
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239 USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR 97239 USA
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Bailey ME, Wang ACJ, Hao J, Janssen WGM, Hara Y, Dumitriu D, Hof PR, Morrison JH. Interactive effects of age and estrogen on cortical neurons: implications for cognitive aging. Neuroscience 2011; 191:148-58. [PMID: 21664255 DOI: 10.1016/j.neuroscience.2011.05.045] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 05/12/2011] [Accepted: 05/14/2011] [Indexed: 12/21/2022]
Abstract
In the past few decades it has become clear that estrogen signaling plays a much larger role in modulating the cognitive centers of the brain than previously thought possible. We have developed a nonhuman primate (NHP) model to investigate the relationships between estradiol (E) and cognitive aging. Our studies of cyclical E treatment in ovariectomized (OVX) young and aged rhesus monkeys have revealed compelling cognitive and synaptic effects of E in the context of aging. Delayed response (DR), a task that is particularly dependent on integrity of dorsolateral prefrontal cortex (dlPFC) area 46 revealed the following: (1) that young OVX rhesus monkeys perform equally well whether treated with E or vehicle (V), and (2) that aged OVX animals given E perform as well as young adults with or without E, whereas OVX V-treated aged animals display significant DR impairment. We have analyzed the structure of layer III pyramidal cells in area 46 in these same monkeys. We found both age and treatment effects on these neurons that are consistent with behavioral data. Briefly, reconstructions of pyramidal neurons in area 46 from these monkeys showed that cyclical E increased the density of small, thin spines in both young and aged monkeys. However, this effect of E was against a background of age-related loss of small, thin spines, leaving aged V-treated monkeys with a particularly low density of these highly plastic spines, and vulnerable to cognitive decline. Our current interpretation is that E not only plays a critically important role in maintaining spine number, but also enables synaptic plasticity through a cyclical increase in small highly plastic spines that may be stabilized in the context of learning. Interestingly, recent studies demonstrate that chronic E is less effective at inducing spinogenesis than cyclical E. We have begun to link certain molecular attributes of excitatory synapses in area 46 to E effects and cognitive performance in these monkeys. Given the importance of synaptic estrogen receptor α (ER-α) in rat hippocampus, we focused our initial studies on synaptic ER-α in area 46. Three key findings have emerged from these studies: (1) synaptic ER-α is present in axospinous synapses in area 46; (2) it is stable across treatment and age groups (which is not the case in rat hippocampus); and (3) the abundance and distribution of synaptic ER-α is a key correlate of individual variation in cognitive performance in certain age and treatment groups. These findings have important implications for the design of hormone treatment strategies for both surgically and naturally menopausal women. This article is part of a Special Issue entitled: Neuroactive Steroids: Focus on Human Brain.
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Affiliation(s)
- M E Bailey
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA
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Daniel JM, Bohacek J. The critical period hypothesis of estrogen effects on cognition: Insights from basic research. Biochim Biophys Acta Gen Subj 2010; 1800:1068-76. [DOI: 10.1016/j.bbagen.2010.01.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 01/09/2010] [Accepted: 01/16/2010] [Indexed: 02/07/2023]
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Asymmetric regulation by estrogen at the cholinergic gene locus in differentiated NG108-15 neuronal cells. Life Sci 2010; 86:839-43. [PMID: 20350555 DOI: 10.1016/j.lfs.2010.03.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 03/06/2010] [Accepted: 03/11/2010] [Indexed: 11/18/2022]
Abstract
AIMS Estrogen acts as a neurogenerative and neuroprotective factor in the cholinergic system. Choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) are regarded as markers of cholinergic neurons. The genes coding these proteins are located at a common locus, the cholinergic gene locus. However, few details concerning activation of the locus have been obtained. We examined the effect of estrogen on the activation pattern of the locus using a cholinergic cell line. MAIN METHODS NG108-15 neuronal cells, as a model of cholinergic neurons, were used. Dose-dependent effects of estradiol (E2) on the gene expression of ChAT and VAChT were quantitatively determined by a real-time RT-PCR. The expression of ChAT mRNA variants was qualitatively evaluated by RT-PCR using specific primers. KEY FINDINGS The expression of ChAT and VAChT mRNA was strongly enhanced with the induction of differentiation. The enhanced expression of ChAT mRNA was further increased dose-dependently by E2 (10(-10) to 10(-7)M), while that of VAChT mRNA did not respond to E2. The up-regulation of ChAT mRNA expression by E2 was abolished by co-treatment with a pure-antagonist of estrogen receptors. A qualitative analysis of ChAT mRNA variants revealed the R types, which share a common sequence with the VAChT gene, and type M ChAT mRNA to mainly be expressed, and that the appearance of these variants was not altered by E2. SIGNIFICANCE The cholinergic gene locus in differentiated NG108-15 neuronal cells is further activated by E2, but the effect is restricted to the transcription of ChAT gene.
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Yague JG, Azcoitia I, DeFelipe J, Garcia-Segura LM, Muñoz A. Aromatase expression in the normal and epileptic human hippocampus. Brain Res 2009; 1315:41-52. [PMID: 19815003 DOI: 10.1016/j.brainres.2009.09.111] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 09/28/2009] [Accepted: 09/28/2009] [Indexed: 12/29/2022]
Abstract
Aromatase is a key enzyme in estrogen biosynthesis that is involved in neuronal plasticity in the rodent hippocampus. Although aromatase mRNA expression has been detected in the human hippocampus, its cellular distribution has yet to be determined. Here, we have examined the immunohistochemical distribution of aromatase in the normal and the epileptic and sclerotic human hippocampus. In both the normal and epileptic hippocampus, aromatase was detected in numerous CA1-CA3 pyramidal neurons, in granule cells of the dentate gyrus and in interneurons that co-expressed the calcium-binding proteins calbindin, calretinin or parvalbumin. However, only a small subpopulation of astrocytes was immunoreactive for aromatase in either the normal and epileptic hippocampus. The widespread expression of aromatase in a large population of neurons in the normal and damaged hippocampus suggests that local estrogen formation may play an important role in human hippocampal function.
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Affiliation(s)
- Josue G Yague
- Instituto Cajal, CSIC, Avenida Doctor Arce 37, E-28002 Madrid, Spain
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31
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Maki PM, Dumas J. Mechanisms of action of estrogen in the brain: insights from human neuroimaging and psychopharmacologic studies. Semin Reprod Med 2009; 27:250-9. [PMID: 19401956 DOI: 10.1055/s-0029-1216278] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Use of estrogen therapy in the perimenopausal and postmenopausal periods has been shown in several clinical trials to help women maintain a premenopausal level of cognitive function. What is not yet fully understood is how the neurobiological effects of estrogen contribute to these cognitive effects. This review explores data from two related bodies of human literature that provide compelling evidence in support of the biological plausibility that estrogen treatment can benefit cognition. The first half of the literature review focuses on studies from the estrogen neuroimaging literature, and the second half focuses on pharmacologic challenge studies assessing estrogen-neurotransmitter interactions. We integrate these two bodies of literature by focusing on the neurophysiologic underpinnings of estrogen effects on cognition and linking these clinical studies to preclinical studies. The focus on verbal memory is important because it is a cognitive function that has been shown to change with estrogen treatment and predict Alzheimer's disease risk but is not addressed by preclinical studies. Overall, we conclude that estrogen interacts with cholinergic and serotonergic systems to affect hippocampal and frontal cortical brain areas and thereby enhance memory, particularly at the retrieval stage.
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Affiliation(s)
- Pauline M Maki
- Departments of Psychiatry and Psychology, Center for Cognitive Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612, USA.
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Browne C, Tobin JR, Voytko ML. Effects of two years of conjugated equine estrogens on cholinergic neurons in young and middle-aged ovariectomized monkeys. Brain Res 2009; 1264:13-23. [PMID: 19401167 DOI: 10.1016/j.brainres.2009.01.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 01/09/2009] [Accepted: 01/11/2009] [Indexed: 01/13/2023]
Abstract
The effect of estrogen on the number and size of cholinergic neurons in the basal forebrain was examined in surgically menopausal young and middle-aged cynomolgus monkeys. Young and middle-aged female monkeys were ovariectomized and treated with conjugated equine estrogens (Premarin) at doses that are equivalent to those currently prescribed to postmenopausal women. In the medial septum/diagonal band (MS/DB), no effect of treatment with Premarin was observed in the cholinergic neurons in either ovariectomized young or middle-aged monkeys. However, the number and size of cholinergic neurons in the MS/DB of middle-aged monkeys was greater than that in the young monkeys. In the nucleus basalis of Meynert (NBM) of middle-aged monkeys, the number of cholinergic neurons in the intermediate region (Ch4i) was greater in Premarin-treated monkeys as compared to controls and numbers of neurons in this region were greater at higher levels of estrogen. No effects of estrogen were observed in other NBM regions in the middle-aged monkeys and the size of cholinergic neurons was unaffected by Premarin. These findings suggest that treatment with Premarin has selective beneficial effects on cholinergic neurons in the basal forebrain but that these effects are both age and region specific.
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Affiliation(s)
- Carole Browne
- Department of Biology, Wake Forest University, Winston-Salem, NC 27106, USA
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33
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Wang VC, Sable HJK, Ju YH, Allred CD, Helferich WG, Korol DL, Schantz SL. Effects of chronic estradiol treatment on delayed spatial alternation and differential reinforcement of low rates of responding. Behav Neurosci 2008; 122:794-804. [PMID: 18729633 DOI: 10.1037/a0012513] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Estrogens have been shown to both enhance and impair cognitive function depending on several factors, including regimen of hormone treatment, age of subject, and task attributes. In rodent models, estradiol tends to enhance spatial learning and impair response or cued learning, but effects on executive functions are less well-studied. In this experiment, spatial working memory and response inhibition were tested using delayed spatial alternation (DSA) and differential reinforcement of low rates of responding (DRL) tasks in ovariectomized rats that were given chronic estradiol via Silastic implants resulting in serum estradiol concentrations of 86.2 +/- 8.2 (SEM) pg/ml. Rats were tested for 25 days DSA with variable delays of 0, 3, 6, 9, and 18 seconds between lever presentations, followed by 30 days on a DRL-15s operant schedule. Estradiol-replaced rats showed a significantly lower proportion of correct responses on the DSA task compared to vehicle-implanted ovariectomized animals. On DRL, estradiol-treated rats showed a lower ratio of reinforced to nonreinforced presses. These data suggest that chronic estrogen exposure may impair rats' abilities on measures of executive function including working memory and response inhibition.
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Affiliation(s)
- Victor C Wang
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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34
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Arad M, Weiner I. Fluctuation of latent inhibition along the estrous cycle in the rat: modeling the cyclicity of symptoms in schizophrenic women? Psychoneuroendocrinology 2008; 33:1401-10. [PMID: 18819755 DOI: 10.1016/j.psyneuen.2008.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 08/03/2008] [Accepted: 08/06/2008] [Indexed: 10/21/2022]
Abstract
Latent inhibition (LI) is a cross-species selective attention phenomenon manifested as poorer conditioning of stimuli that had been experienced as irrelevant prior to conditioning. Disruption of LI by pro-psychotic agents such as amphetamine and its restoration by antipsychotic drugs (APDs) is a well-established model of psychotic symptoms of schizophrenia. There is evidence that in schizophrenic women symptom severity and treatment response fluctuate along the menstrual cycle. Here we tested whether hormonal fluctuation along the estrous cycle in female rats (as determined indirectly via the cellular composition of the vaginal smears) would modulate the expression of LI and its response to APDs. The results showed that LI was seen if rats were in estrus during pre-exposure stage and in metestrus during the conditioning stage of the LI procedure (estrus-metestrus) but not along the remaining sequential phases of the cycle (metestrus-diestrus, diestrus-proestrus and proestrus-estrus). Additionally, the efficacy of typical and atypical APDs, haloperidol and clozapine, respectively, in restoring LI depended on estrous condition. Only LI disruption in proestrus-estrus exhibited sensitivity to both APDs, whereas LI disruption in the other two phases was alleviated by clozapine but not haloperidol. Our results show for the first time that both the expression of LI and its sensitivity to APDs are modulated along the estrous cycle, consistent with fluctuations in psychotic symptoms and response to APDs seen along women's menstrual cycle. Importantly, the results indicate that although both low and high levels of hormones may give rise to psychotic-like behavior as manifested in LI loss, the pro-psychotic state associated with low hormonal level is more severe due to reduced sensitivity to typical APDs. The latter constellation may mimic states of increased vulnerability to psychosis coupled with reduced treatment response documented in schizophrenic women during periods associated with low levels of hormones.
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Affiliation(s)
- Michal Arad
- Department of Psychology, Tel-Aviv University, Tel-Aviv 69978, Israel.
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35
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36
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Bohacek J, Bearl AM, Daniel JM. Long-term ovarian hormone deprivation alters the ability of subsequent oestradiol replacement to regulate choline acetyltransferase protein levels in the hippocampus and prefrontal cortex of middle-aged rats. J Neuroendocrinol 2008; 20:1023-7. [PMID: 18540996 DOI: 10.1111/j.1365-2826.2008.01752.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of oestrogen replacement therapy in preventing or delaying age-associated cognitive decline is controversial. Therapy success may critically depend on the time of treatment initiation following cessation of ovarian function. The present study aimed to assess, in middle-aged rats, whether the ability of oestradiol to modulate the cholinergic system depends on the timing of treatment initiation following ovariectomy. Using western blotting, protein levels of choline acetyltransferase (ChAT) were measured in the hippocampus and prefrontal cortex (PFC), which are both important areas with respect to cognitive function. In an initial experiment, we established the effects of oestradiol delivered via implanted capsules on ChAT levels in the hippocampus and PFC of young adult animals. In a second experiment, we tested the ability of the same oestradiol treatment paradigm to affect ChAT protein in 15-month-old middle-aged rats that had been ovariectomised either at the age of 10 months or at 15 months. In both experiments, rats were sacrificed 10 days after receiving implants and ChAT protein levels were measured. In both young adult and middle-aged animals, oestradiol treatment initiated immediately after ovariectomy significantly increased ChAT levels in the hippocampus but not in the PFC compared to cholesterol control treatment. However, when oestradiol treatment was initiated 5 months after ovariectomy, it failed to significantly increase ChAT levels in the hippocampus, but did so in the PFC. These data indicate that, after prolonged ovarian hormone deprivation, the ability of subsequent oestradiol treatment to modulate ChAT protein levels is altered in a site-specific manner.
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Affiliation(s)
- J Bohacek
- Program in Neuroscience, Tulane University, New Orleans, LA 70118, USA
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37
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Voytko ML, Higgs CJ, Murray R. Differential effects on visual and spatial recognition memory of a novel hormone therapy regimen of estrogen alone or combined with progesterone in older surgically menopausal monkeys. Neuroscience 2008; 154:1205-17. [PMID: 18554815 PMCID: PMC2662767 DOI: 10.1016/j.neuroscience.2008.04.064] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2008] [Revised: 04/29/2008] [Accepted: 04/30/2008] [Indexed: 11/25/2022]
Abstract
Building upon our initial studies in young adult surgically menopausal monkeys, this study examined the effects of a novel schedule of administration of estradiol therapy alone, or in combination with progesterone, on visual and spatial recognition memory in older monkeys. Monkeys were preoperatively trained on a delayed matching-to-sample task and a delayed response task. At the time of ovariectomy, monkeys began their hormonal treatments and were cognitively assessed at 2, 12 and 24 weeks following treatment initiation. A schedule of hormone administration was used that closely modeled the normal fluctuations of hormones during the course of a normal primate menstrual cycle. Monkeys receiving placebo had lower levels of accuracy than monkeys receiving estrogen therapies on the delayed matching-to-sample task that were not apparent until 12 weeks following initiation of therapy and were no longer detected at the 24-week assessment. There was no effect of hormone therapy on accuracy in the delayed response task at any of the postoperative assessments. In both tasks, monkeys treated with estrogen plus progesterone had longer choice response latencies, especially on trials in which they made errors; however these effects did not influence accuracy measures in these animals. Our findings indicate that visual recognition ability may be more sensitive than spatial recognition memory to this novel hormone therapy regimen, that treatment with estradiol plus progesterone was equivalent to that of estradiol alone, and that neither therapy had significant negative impact on memory profiles.
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Affiliation(s)
- M L Voytko
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
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38
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Thalamo-Basal Ganglia connectivity in postmenopausal women receiving estrogen therapy. Neurochem Res 2008; 34:234-7. [PMID: 18535904 DOI: 10.1007/s11064-008-9756-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Accepted: 05/19/2008] [Indexed: 01/23/2023]
Abstract
Cumulative data on the effects of estrogen therapy (ET) on brain function in postmenopausal women suggests that ET influences cerebral metabolism and may protect against age-related declines in various domains of cognitive function. The beneficial cognitive effects of ET may relate to its modulation of the thalamic-striatum cholinergic and dopaminergic systems, as the activity of both neurotransmitter systems in the thalamus appears to be positively influenced by estrogen. In the current study, we attempted to evaluated regional cerebral brain metabolism utilizing [18F]-fluorodeoxyglucose positron emission tomography in 11 healthy recently-postmenopausal women on ET (ET+) in comparison to 11 recently-postmenopausal and ET-naïve women (ET-) in order to assess the effects of ET on cholinergic and dopaminergic system regulation. Results showed thalamo-basal ganglia connectivity among ET+ women but not among ET- women. The presence of connectivity in the thalamo-striatal pathway in recently postmenopausal women suggests estrogen effects in preserving integrity of the cholinergic and dopaminergic systems. The results also suggest that ET initiated at or near the menopausal transition may modulate brain aging by mediating complex sensory-motor functions.
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Furey ML, Pietrini P, Haxby JV, Drevets WC. Selective effects of cholinergic modulation on task performance during selective attention. Neuropsychopharmacology 2008; 33:913-23. [PMID: 17534379 PMCID: PMC3250310 DOI: 10.1038/sj.npp.1301461] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The cholinergic neurotransmitter system is critically linked to cognitive functions including attention. The current studies were designed to evaluate the effect of a cholinergic agonist and an antagonist on performance during a selective visual attention task where the inherent salience of attended/unattended stimuli was modulated. Two randomized, placebo-controlled, crossover studies were performed, one (n=9) with the anticholinesterase physostigmine (1.0 mg/h), and the other (n=30) with the anticholinergic scopolamine (0.4 mc/kg). During the task, two double-exposure pictures of faces and houses were presented side by side. Subjects were cued to attend to either the face or the house component of the stimuli, and were instructed to perform a matching task with the two exemplars from the attended category. The cue changed every 4-7 trials to instruct subjects to shift attention from one stimulus component to the other. During placebo in both studies, reaction time (RT) associated with the first trial following a cued shift in attention was longer than RT associated with later trials (p<0.05); RT also was significantly longer when attending to houses than to faces (p<0.05). Physostigmine decreased RT relative to placebo preferentially during trials greater than one (p<0.05), with no change during trial one; and decreased RT preferentially during the attention to houses condition (p<0.05) vs attention to faces. Scopolamine increased RT relative to placebo selectively during trials greater than one (p<0.05), and preferentially increased RT during the attention to faces condition (p<0.05). The results suggest that enhancement or impairment of cholinergic activity preferentially influences the maintenance of selective attention (ie trials greater than 1). Moreover, effects of cholinergic manipulation depend on the selective attention condition (ie faces vs houses), which may suggest that cholinergic activity interacts with stimulus salience. The findings are discussed within the context of the role of acetylcholine both in stimulus processing and stimulus salience, and in establishing attention biases through top-down and bottom-up mechanisms of attention.
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Affiliation(s)
- Maura L Furey
- Mood and Anxiety Disorders Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
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40
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Dumas J, Hancur-Bucci C, Naylor M, Sites C, Newhouse P. Estradiol interacts with the cholinergic system to affect verbal memory in postmenopausal women: evidence for the critical period hypothesis. Horm Behav 2008; 53:159-69. [PMID: 17964576 PMCID: PMC2435492 DOI: 10.1016/j.yhbeh.2007.09.011] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 08/31/2007] [Accepted: 09/18/2007] [Indexed: 11/17/2022]
Abstract
Estradiol has been shown to interact with the cholinergic system to affect cognition in postmenopausal women. This study further investigated the interaction of estradiol and cholinergic system functioning on verbal memory and attention in two groups of healthy younger (ages 50-62) and older (ages 70-81) postmenopausal women. Twenty-two postmenopausal women were randomly and blindly placed on 1 mg of 17-beta estradiol orally for 1 month then 2 mg for 2 months or matching placebo pills after which they participated in three anticholinergic challenge sessions when verbal memory and attention were assessed. Subjects were administered either the antimuscarinic drug scopolamine (SCOP), the antinicotinic drug mecamylamine (MECA), or placebo. After the first challenge phase, they were crossed over to the other hormone treatment for another 3 months and repeated the challenges. Results showed that estradiol pretreatment significantly attenuated the anticholinergic drug-induced impairments on a test of episodic memory (the Buschke Selective Reminding Task) for the younger group only, while estradiol treatment impaired performance of the older group. The results suggest that younger subjects may experience more cholinergic benefit from estradiol treatment than older subjects, supporting the concept of a critical period for postmenopausal estrogen use.
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Affiliation(s)
- Julie Dumas
- Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine
| | - Catherine Hancur-Bucci
- Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine
| | - Magdalena Naylor
- Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine
| | - Cynthia Sites
- Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, University of Alabama School of Medicine
| | - Paul Newhouse
- Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine
- Address for Correspondence (PN): Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine, 1 South Prospect St., Burlington, VT 05401, Voice: (802) 847-4560, Fax: (802) 847-7889,
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Sherwin BB, Henry JF. Brain aging modulates the neuroprotective effects of estrogen on selective aspects of cognition in women: a critical review. Front Neuroendocrinol 2008; 29:88-113. [PMID: 17980408 DOI: 10.1016/j.yfrne.2007.08.002] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 07/17/2007] [Accepted: 08/14/2007] [Indexed: 11/28/2022]
Abstract
Although there is now a substantial literature on the putative neuroprotective effects of estrogen on cognitive functioning in postmenopausal women, it is replete with inconsistencies. The critical period hypothesis, posited several years ago, attempts to account for the discrepancies in this literature by positing that estrogen treatment (ET) will protect aspects of cognition in older women only when treatment is initiated soon after the menopause. Indeed, evidence from basic neuroscience and from the animal and human literature reviewed herein provides compelling support for the critical period hypothesis. Although it is not known with certainty why estrogen does not protect cognition and may even cause harm when administered to women over the age of 65years, it is likely that the events that characterize brain aging, such as a reduction in brain volume and in neuronal size, alterations in neurotransmitter systems, and a decrease in dendritic spine numbers, form an unfavorable background that precludes a neuroprotective effects of exogenous estrogen on the brain. Other factors that have likely contributed to the discrepancies in the estrogen-cognition literature include differences in the estrogen compounds used, their route of administration, cyclic versus continuous regimens, and the concomitant use of progestins. This critical analysis attempts to define conditions under which ET may protect aspects of cognition in aging women while also considering the cost/benefit ratio for the treatment of women aged 50-59years. Suggestions for specific future research questions are also addressed.
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Affiliation(s)
- Barbara B Sherwin
- McGill University, Department of Psychology, 1205 Dr. Penfield Avenue, Montreal, Que., Canada.
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Gasbarri A, Pompili A, d'Onofrio A, Abreu C, Tavares M. Working Memory for Emotional Facial Expressions: Role of Estrogen in Humans and Non-Human Primates. Rev Neurosci 2008; 19:129-48. [DOI: 10.1515/revneuro.2008.19.2-3.129] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kofman O, Shavit Y, Ashkenazi S, Gabay S. Habituation, discrimination and anxiety in transgenic mice overexpressing acetylcholinesterase splice variants. Brain Res 2007; 1185:170-8. [DOI: 10.1016/j.brainres.2007.09.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 09/04/2007] [Accepted: 09/06/2007] [Indexed: 10/22/2022]
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Alejandre-Gomez M, Garcia-Segura LM, Gonzalez-Burgos I. Administration of an inhibitor of estrogen biosynthesis facilitates working memory acquisition in male rats. Neurosci Res 2007; 58:272-7. [PMID: 17467093 DOI: 10.1016/j.neures.2007.03.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 03/20/2007] [Accepted: 03/23/2007] [Indexed: 11/22/2022]
Abstract
Estradiol is known to improve performance of some working memory tasks in female animals and post-menopausal women. In females the main source of estradiol is the ovary. In addition, in both males and females estradiol is synthesized in extragonadal tissues. The role of non-ovarian estradiol synthesis on cognitive abilities has not been adequately explored. In the sent study we have assessed the effect of an inhibitor of aromatase, the enzyme that produces estradiol from testosterone, on egocentric working memory in male rats. Sprague-Dawley adult male rats received the intra-esophageal administration of the aromatase inhibitor letrozole (2.5 mg/kg), or vehicle. Rats treated with the aromatase inhibitor committed less errors than untreated animals or animals treated with vehicle, when tested in a cross-arms maze. Retention and retrieval stages were unaffected by aromatase inhibition. This finding indicates that aromatase activity is involved in egocentric working memory performance. The effect of the aromatase inhibitor on working memory may be due to the increase in testosterone levels resulting from aromatase inhibition or to modifications in the availability of estradiol in the brain.
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Affiliation(s)
- Misael Alejandre-Gomez
- Laboratorio de Psicobiologia, Centro de Investigacion Biomedica de Michoacan, Instituto Mexicano del Seguro Social, A.P. 7-70 C.P. 58261, Morelia, Mich., Mexico
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Hao J, Rapp PR, Janssen WGM, Lou W, Lasley BL, Hof PR, Morrison JH. Interactive effects of age and estrogen on cognition and pyramidal neurons in monkey prefrontal cortex. Proc Natl Acad Sci U S A 2007; 104:11465-70. [PMID: 17592140 PMCID: PMC2040921 DOI: 10.1073/pnas.0704757104] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We previously reported that long-term cyclic estrogen (E) treatment reverses age-related impairment of cognitive function mediated by the dorsolateral prefrontal cortex (dlPFC) in ovariectomized (OVX) female rhesus monkeys, and that E induces a corresponding increase in spine density in layer III dlPFC pyramidal neurons. We have now investigated the effects of the same E treatment in young adult females. In contrast to the results for aged monkeys, E treatment failed to enhance dlPFC-dependent task performance relative to vehicle control values (group young OVX+Veh) but nonetheless led to a robust increase in spine density. This response was accompanied by a decline in dendritic length, however, such that the total number of spines per neuron was equivalent in young OVX+Veh and OVX+E groups. Robust effects of chronological age, independent of ovarian hormone status, were also observed, comprising significant age-related declines in dendritic length and spine density, with a preferential decrease in small spines in the aged groups. Notably, the spine effects were partially reversed by cyclic E administration, although young OVX+Veh monkeys still had a higher complement of small spines than did aged E treated monkeys. In summary, layer III pyramidal neurons in the dlPFC are sensitive to ovarian hormone status in both young and aged monkeys, but these effects are not entirely equivalent across age groups. The results also suggest that the cognitive benefit of E treatment in aged monkeys is mediated by enabling synaptic plasticity through a cyclical increase in small, highly plastic dendritic spines in the primate dlPFC.
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Affiliation(s)
- Jiandong Hao
- *Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories
| | - Peter R. Rapp
- *Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories
- Department of Geriatrics and Adult Development, and
| | | | - Wendy Lou
- Department of Public Health Sciences, University of Toronto, Toronto, ON, Canada M5T 3M7; and
| | - Bill L. Lasley
- Center for Health and the Environment and
- California National Primate Research Center, University of California, Davis, CA 95616
| | - Patrick R. Hof
- *Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories
- Department of Geriatrics and Adult Development, and
- Computational Neurobiology and Imaging Center, Mount Sinai School of Medicine, New York, NY 10029
| | - John H. Morrison
- *Fishberg Department of Neuroscience and Kastor Neurobiology of Aging Laboratories
- Department of Geriatrics and Adult Development, and
- **To whom correspondence may be addressed at:
Department of Neuroscience, Box 1065, Mount Sinai School of Medicine, New York, NY 10029. E-mail:
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Schumacher M, Guennoun R, Ghoumari A, Massaad C, Robert F, El-Etr M, Akwa Y, Rajkowski K, Baulieu EE. Novel perspectives for progesterone in hormone replacement therapy, with special reference to the nervous system. Endocr Rev 2007; 28:387-439. [PMID: 17431228 DOI: 10.1210/er.2006-0050] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The utility and safety of postmenopausal hormone replacement therapy has recently been put into question by large clinical trials. Their outcome has been extensively commented upon, but discussions have mainly been limited to the effects of estrogens. In fact, progestagens are generally only considered with respect to their usefulness in preventing estrogen stimulation of uterine hyperplasia and malignancy. In addition, various risks have been attributed to progestagens and their omission from hormone replacement therapy has been considered, but this may underestimate their potential benefits and therapeutic promises. A major reason for the controversial reputation of progestagens is that they are generally considered as a single class. Moreover, the term progesterone is often used as a generic one for the different types of both natural and synthetic progestagens. This is not appropriate because natural progesterone has properties very distinct from the synthetic progestins. Within the nervous system, the neuroprotective and promyelinating effects of progesterone are promising, not only for preventing but also for reversing age-dependent changes and dysfunctions. There is indeed strong evidence that the aging nervous system remains at least to some extent sensitive to these beneficial effects of progesterone. The actions of progesterone in peripheral target tissues including breast, blood vessels, and bones are less well understood, but there is evidence for the beneficial effects of progesterone. The variety of signaling mechanisms of progesterone offers exciting possibilities for the development of more selective, efficient, and safe progestagens. The recognition that progesterone is synthesized by neurons and glial cells requires a reevaluation of hormonal aging.
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Affiliation(s)
- Michael Schumacher
- INSERM UMR 788, 80, rue du Général Leclerc, 94276 Kremlin-Bicêtre, France.
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Abstract
Although there is compelling evidence from small randomised controlled trials and cross-sectional studies indicating that oestrogen helps to protect against cognitive ageing in women, the findings of the large, Women's Health Initiative Memory Study failed to support the earlier findings. The attempt to resolve these discrepancies led to the formulation of the Critical Period Hypothesis which holds that oestrogen has maximal protective benefits on cognition in women when it is initiated closely in time to a natural or surgical menopause but not when treatment is begun decades after the menopause. This article reviews the evidence from basic neuroendocrinology, from animal behavioural studies and from human studies that supports the critical period hypothesis. In view of the promise of this hypothesis and its considerable clinical implications, a direct test of its validity is warranted.
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Affiliation(s)
- B B Sherwin
- Department of Psychology & Department of Obstetrics and Gynaecology, McGill University, Montreal, Canada.
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Dumas J, Hancur-Bucci C, Naylor M, Sites C, Newhouse P. Estrogen treatment effects on anticholinergic-induced cognitive dysfunction in normal postmenopausal women. Neuropsychopharmacology 2006; 31:2065-78. [PMID: 16482084 DOI: 10.1038/sj.npp.1301042] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Estrogen has been shown to interact with the cholinergic system and influence cognition in animal models. This study investigated the interaction of estrogen and cholinergic system functioning and the effects of this interaction on cognitive task performance in healthy older women. Fifteen post-menopausal women were randomly and blindly placed on 1 mg of 17-beta estradiol or placebo for 3 months after which they participated in five anticholinergic challenge sessions, where they were administered one of two doses of the antimuscarinic drug scopolamine (SCOP) or the antinicotinic drug mecamylamine (MECA) or placebo. After the first challenge phase, they were crossed over to the other hormone treatment for another 3 months and repeated the challenges. Performance in multiple domains of cognition was assessed during anticholinergic drug challenge, including attention and verbal and nonverbal learning and memory. Results showed that estrogen pretreatment attenuated the anticholinergic drug-induced impairments on tests of attention and tasks with speed components. This study is the first to demonstrate the interaction of estrogen and the cholinergic system and the effects on cognitive performance in humans. The results suggest that estrogen status may affect cholinergic system tone and may be important for cholinergic system integrity.
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Affiliation(s)
- Julie Dumas
- Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine, Burlington, VT 05401, USA
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Gresack JE, Frick KM. Effects of continuous and intermittent estrogen treatments on memory in aging female mice. Brain Res 2006; 1115:135-47. [PMID: 16920082 DOI: 10.1016/j.brainres.2006.07.067] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Revised: 07/20/2006] [Accepted: 07/21/2006] [Indexed: 10/24/2022]
Abstract
The manner in which hormone therapy is given to postmenopausal women may significantly influence its ability to reduce age-associated memory loss. To test the hypothesis that a regimen that approximates the timing of estrogen surges in the natural cycle is more beneficial for memory than a regimen that provides continuous levels of estrogen, we examined the effects of continuous and intermittent estrogen regimens on spatial and object memory in aging female mice. Mice (18 months) were treated with 0.2 mg/kg 17beta-estradiol (E(2)) or vehicle (VEH) for 3 months following ovariectomy. A fast-acting water-soluble cyclodextrin-encapsulated E(2) was used to ensure metabolism within 24 h. Vehicle-treated mice received daily injections of 2-hydroxypropyl-beta-cyclodextrin vehicle. The continuous estradiol group (Contin E(2)) was injected daily with estradiol. The intermittent group (Twice/wk E(2)) received estradiol every 4 days and vehicle on all other days. Mice (21 months) were tested in water-escape motivated 8-arm radial arm maze (WRAM) and object recognition tasks. During WRAM acquisition, the Twice/wk E(2) group committed significantly more reference memory errors than VEH and Contin E(2) groups, and tended to make more working memory errors than the VEH group. The Contin E(2) group did not differ from VEH on either WRAM measure. Additionally, the Twice/wk E(2) group tended to exhibit impaired object recognition. Thus, neither treatment improved spatial or object memory. Indeed, intermittent estradiol was detrimental to both types of memory. These results suggest that the timing of administration may play an important role in the mnemonic response of aging females to estrogen.
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Affiliation(s)
- Jodi E Gresack
- Department of Psychology, Yale University, New Haven, CT 06520, USA
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Sohrabji F, Bake S. Age-related changes in neuroprotection: is estrogen pro-inflammatory for the reproductive senescent brain? Endocrine 2006; 29:191-7. [PMID: 16785595 DOI: 10.1385/endo:29:2:191] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Revised: 11/30/1999] [Accepted: 10/25/2005] [Indexed: 11/11/2022]
Abstract
Estrogen replacement therapy (ERT) is widely prescribed to postmenopausal women for relief from the adverse vasomotor effects of menopause, to reduce bone loss, to improve cardiovascular health, and to protect against metabolic disorders. However, there is now greater awareness of the increased risk to benefit ratio from the recently concluded Women's Health Initiative Memory Study (WHIMS), which reported that ERT increased the risk of cognitive impairment and dementia in elderly women. Studies from the experimental literature indicate that while estrogen is neuroprotective in many instances, estrogen replacement can be deleterious in some cases. These differences may be partly due to the age and species of the experimental model. The majority of the experimental data comes from studies where the age or endocrine status of the animal model is not comparable to that of menopausal or postmenopausal women, such as those in the WHIMS study. In this review, we will focus on age-related changes in estrogen's neuroprotective effects and evidence that reproductive senescence-related changes in the blood-brain barrier and the immune system may result in deleterious consequences for ERT.
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Affiliation(s)
- Farida Sohrabji
- Neuroscience and Experimental Therapeutics, Department of Human Anatomy & Medical Neurobiology, TAMHSC College of Medicine, College Station, TX 77843-1114, USA.
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