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Ovariectomy reduces cholinergic modulation of excitatory synaptic transmission in the rat entorhinal cortex. PLoS One 2022; 17:e0271131. [PMID: 35939438 PMCID: PMC9359571 DOI: 10.1371/journal.pone.0271131] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 06/23/2022] [Indexed: 11/20/2022] Open
Abstract
Estrogens are thought to contribute to cognitive function in part by promoting the function of basal forebrain cholinergic neurons that project to the hippocampus and cortical regions including the entorhinal cortex. Reductions in estrogens may alter cognition by reducing the function of cholinergic inputs to both the hippocampus and entorhinal cortex. In the present study, we assessed the effects of ovariectomy on proteins associated with cholinergic synapses in the entorhinal cortex. Ovariectomy was conducted at PD63, and tissue was obtained on PD84 to 89 to quantify changes in the degradative enzyme acetylcholinesterase, the vesicular acetylcholine transporter, and muscarinic M1 receptor protein. Although the vesicular acetylcholine transporter was unaffected, ovariectomy reduced both acetylcholinesterase and M1 receptor protein, and these reductions were prevented by chronic replacement of 17β-estradiol following ovariectomy. We also assessed the effects of ovariectomy on the cholinergic modulation of excitatory transmission, by comparing the effects of the acetylcholinesterase inhibitor eserine on evoked excitatory synaptic field potentials in brain slices obtained from intact rats, and from ovariectomized rats with or without 17β-estradiol replacement. Eserine is known to prolong the effects of endogenously released acetylcholine, resulting in an M1-like mediated reduction of glutamate release at excitatory synapses. The reduction in excitatory synaptic potentials in layer II of the entorhinal cortex induced by 15-min application of 10 μM eserine was greatly reduced in slices from ovariectomized rats as compared to intact rats and ovariectomized rats with replacement of 17β-estradiol. The reduced modulatory effect of eserine is consistent with the observed changes in cholinergic proteins, and suggests that reductions in 17β-estradiol following ovariectomy lead to impaired cholinergic function within the entorhinal cortex.
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Prakapenka AV, Peña VL, Strouse I, Northup-Smith S, Schrier A, Ahmed K, Bimonte-Nelson HA, Sirianni RW. Intranasal 17β-Estradiol Modulates Spatial Learning and Memory in a Rat Model of Surgical Menopause. Pharmaceutics 2020; 12:E1225. [PMID: 33348722 PMCID: PMC7766209 DOI: 10.3390/pharmaceutics12121225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/01/2020] [Accepted: 12/08/2020] [Indexed: 01/23/2023] Open
Abstract
Exogenously administered 17β-estradiol (E2) can improve spatial learning and memory, although E2 also exerts undesired effects on peripheral organs. Clinically, E2 has been solubilized in cyclodextrin for intranasal administration, which enhances brain-specific delivery. Prior work shows that the cyclodextrin structure impacts region-specific brain distribution of intranasally administered small molecules. Here, we investigated (1) cyclodextrin type-specific modulation of intranasal E2 brain distribution, and (2) cognitive and peripheral tissue effects of intranasal E2 in middle-aged ovariectomized rats. First, brain and peripheral organ distribution of intranasally administered, tritiated E2 was measured for E2 solubilized freely or in one of four cyclodextrin formulations. The E2-cyclodextrin formulation with greatest E2 uptake in cognitive brain regions versus uterine horns was then compared to free E2 on learning, memory, and uterine measures. Free E2 improved spatial reference memory, whereas E2-cyclodextrin impaired spatial working memory compared to their respective controls. Both E2 formulations increased uterine horn weights relative to controls, with E2-cyclodextrin resulting in the greatest uterine horn weight, suggesting increased uterine stimulation. Thus, intranasal administration of freely solubilized E2 is a strategic delivery tool that can yield a cognitively beneficial impact of the hormone alongside decreased peripheral effects compared to intranasal administration of cyclodextrin solubilized E2.
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Affiliation(s)
- Alesia V. Prakapenka
- Department of Psychology, Arizona State University, Tempe, AZ 85281, USA; (A.V.P.); (V.L.P.); (I.S.); (S.N.-S.); (A.S.); (K.A.); (H.A.B.-N.)
- School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
- Arizona Alzheimer’s Consortium, Phoenix, AZ 85014, USA
| | - Veronica L. Peña
- Department of Psychology, Arizona State University, Tempe, AZ 85281, USA; (A.V.P.); (V.L.P.); (I.S.); (S.N.-S.); (A.S.); (K.A.); (H.A.B.-N.)
- Arizona Alzheimer’s Consortium, Phoenix, AZ 85014, USA
| | - Isabel Strouse
- Department of Psychology, Arizona State University, Tempe, AZ 85281, USA; (A.V.P.); (V.L.P.); (I.S.); (S.N.-S.); (A.S.); (K.A.); (H.A.B.-N.)
- Arizona Alzheimer’s Consortium, Phoenix, AZ 85014, USA
| | - Steven Northup-Smith
- Department of Psychology, Arizona State University, Tempe, AZ 85281, USA; (A.V.P.); (V.L.P.); (I.S.); (S.N.-S.); (A.S.); (K.A.); (H.A.B.-N.)
- Arizona Alzheimer’s Consortium, Phoenix, AZ 85014, USA
| | - Ally Schrier
- Department of Psychology, Arizona State University, Tempe, AZ 85281, USA; (A.V.P.); (V.L.P.); (I.S.); (S.N.-S.); (A.S.); (K.A.); (H.A.B.-N.)
- Arizona Alzheimer’s Consortium, Phoenix, AZ 85014, USA
| | - Kinza Ahmed
- Department of Psychology, Arizona State University, Tempe, AZ 85281, USA; (A.V.P.); (V.L.P.); (I.S.); (S.N.-S.); (A.S.); (K.A.); (H.A.B.-N.)
- Arizona Alzheimer’s Consortium, Phoenix, AZ 85014, USA
| | - Heather A. Bimonte-Nelson
- Department of Psychology, Arizona State University, Tempe, AZ 85281, USA; (A.V.P.); (V.L.P.); (I.S.); (S.N.-S.); (A.S.); (K.A.); (H.A.B.-N.)
- Arizona Alzheimer’s Consortium, Phoenix, AZ 85014, USA
| | - Rachael W. Sirianni
- Vivian L. Smith Department of Neurosurgery, UTHealth Medical School, Houston, TX 77030, USA
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Renczés E, Borbélyová V, Steinhardt M, Höpfner T, Stehle T, Ostatníková D, Celec P. The Role of Estrogen in Anxiety-Like Behavior and Memory of Middle-Aged Female Rats. Front Endocrinol (Lausanne) 2020; 11:570560. [PMID: 33117285 PMCID: PMC7575693 DOI: 10.3389/fendo.2020.570560] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/02/2020] [Indexed: 12/21/2022] Open
Abstract
Aging in women is associated with low estrogen, but also with cognitive decline and affective disorders. Whether low estrogen is causally responsible for these behavioral symptoms is not clear. Thus, we aimed to examine the role of estradiol in anxiety-like behavior and memory in rats at middle age. Twelve-month old female rats underwent ovariectomy (OVX) or were treated with 1 mg/kg of letrozole-an aromatase inhibitor. In half of the OVX females, 10 μg/kg of 17β-estradiol was supplemented daily for 4 weeks. Vehicle-treated sham-operated and OVX females served as controls. For behavioral assessment open field, elevated plus maze and novel object recognition tests were performed. Interaction between ovarian condition and additional treatment had the main effect on anxiety-like behavior of rats in the open field test. In comparison to control females, OVX females entered less frequently into the center zone of the open field (p < 0.01) and showed lower novel object discrimination (p = 0.05). However, estradiol-supplemented OVX rats had higher number of center-zone entries (p < 0.01), spent more time in the center zone (p < 0.05), and showed lower thigmotaxis (p < 0.01) when compared to OVX group. None of the hormonal manipulations affected anxiety-like behavior in the elevated plus maze test significantly, but a mild effect of interaction between ovarian condition and treatment was shown (p = 0.05). In conclusion, ovariectomy had slight negative effect on open-field ambulation and short-term recognition memory in middle-aged rats. In addition, a test-specific anxiolytic effect of estradiol supplementation was found. In contrast, letrozole treatment neither affected anxiety-like behavior nor memory.
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Affiliation(s)
- Emese Renczés
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Veronika Borbélyová
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Manuel Steinhardt
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Tim Höpfner
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Thomas Stehle
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Daniela Ostatníková
- Institute of Physiology, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Peter Celec
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
- Institute of Pathophysiology, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
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Tao X, Yan M, Wang L, Zhou Y, Wang Z, Xia T, Liu X, Pan R, Chang Q. Effects of estrogen deprivation on memory and expression of related proteins in ovariectomized mice. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:356. [PMID: 32355800 PMCID: PMC7186664 DOI: 10.21037/atm.2020.02.57] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background The ovariectomized (OVX) rodent model is most widely used for studying the influence of estrogen deprivation on memory. However, the results of these studies are inconsistent, in that the memory of OVX rodents shows either impairment or no change. These inconsistent outcomes increase the difficulty of researching neurochemical mechanisms and evaluating drug efficacy. One possible explanation for these discrepancies might be that the time point for memory examination after OVX varies considerably among studies. The aim of our study was to investigate the effects of estrogen deprivation on memory and the expression of memory-related proteins at different times after OVX. Methods Novel object recognition (NOR), step-through passive avoidance (STPA) and the Morris water maze (MWM) were performed to evaluate the memory performance of mice at different times after OVX. The expressions of BDNF, TrkB, ULK1 and LC3II/LC3I in the hippocampus were also assessed to explore the relevant mechanisms. Results After OVX, a significant memory impairment was found in the STPA test at 4 weeks. In the NOR and MWM tests, however, memory deficits were not observed until 8 weeks post-OVX. Interestingly, at 8 weeks, a memory rebound was found in the STPA test. In the hippocampus, the levels of BDNF and TrkB in OVX mice were markedly decreased at 4 and 8 weeks. Subsequently, a significant decrease in the ULK1 and LC3II/LC3I level in OVX mice was observed at 8 weeks. Conclusions Memory impairment in mice was observed as early as 4 weeks after OVX, although there was a possibility of memory rebound with the prolongation of estrogen deprivation. Eight weeks of estrogen deprivation would be more likely to induce hippocampus-dependent memory impairment. This progressive impairment of memory might be due to the downregulation of the BDNF/TrkB signaling pathway at the early post-OVX stage, while the decrease of autophagy level in the later stage might also contribute to these progressive alterations. The underlying relationship between the BDNF/TrkB signaling pathway and autophagy in this progressive impairment of memory requires further study.
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Affiliation(s)
- Xue Tao
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Mingzhu Yan
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Lisha Wang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Yunfeng Zhou
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Zhi Wang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Tianji Xia
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Xinmin Liu
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China.,National Key Laboratory of Human Factors Engineering and the State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing 100094, China
| | - Ruile Pan
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Qi Chang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
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Wang X, Meng Z, Wang J, Zhou H, Wu Y, Wu J. Enriched environment improves working memory impairment of mice with traumatic brain injury by enhancing histone acetylation in the prefrontal cortex. PeerJ 2018; 6:e6113. [PMID: 30568864 PMCID: PMC6287579 DOI: 10.7717/peerj.6113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/15/2018] [Indexed: 01/09/2023] Open
Abstract
Working memory impairment is a common cognitive dysfunction after traumatic brain injury (TBI), which severely affects the quality of life of patients. Acetylcholine is a neurotransmitter which is closely related to cognitive functions. In addition, epigenetic modifications are also related to cognitive functions. A neurorehabilitation strategy, enriched environment (EE) intervention, has been widely used to improve cognitive impairment. However, studies of the mechanism of EE on cholinergic system and epigenetic modifications in mouse with TBI have not been reported yet. In this paper, a mouse model with traumatic frontal lobe injury was established, and the mechanism on EE for the mice with TBI was explored. It was found that EE could improve Y-maze performance of mice with TBI, the function of cholinergic system, and the imbalance of acetylation homeostasis in the prefrontal cortex of contralateral side of TBI. In addition, EE also could increase the level of CREB binding protein and histones H3 acetylation at ChAT gene promoter region in the prefrontal cortex of contralateral side of TBI. These indicate that EE has an important effect on the improvement of working memory impairment and the underlying mechanism may involve in histones H3 acetylation at ChAT gene promoter regions in the prefrontal cortex.
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Affiliation(s)
- Xin Wang
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, PR China.,Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu, PR China
| | - Zhaoxiang Meng
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu, PR China
| | - Jibing Wang
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu, PR China
| | - Hongyu Zhou
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu, PR China
| | - Yi Wu
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Junfa Wu
- Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, PR China
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Xiao Q, Luo Y, Lv F, He Q, Wu H, Chao F, Qiu X, Zhang L, Gao Y, Huang C, Wang S, Zhou C, Zhang Y, Jiang L, Tang Y. Protective Effects of 17β-Estradiol on Hippocampal Myelinated Fibers in Ovariectomized Middle-aged Rats. Neuroscience 2018; 385:143-153. [PMID: 29908214 DOI: 10.1016/j.neuroscience.2018.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 06/01/2018] [Accepted: 06/04/2018] [Indexed: 12/14/2022]
Abstract
Estrogen replacement therapy (ERT) improves hippocampus-dependent cognition. This study investigated the impact of estrogen on hippocampal volume, CA1 subfield volume and myelinated fibers in the CA1 subfield of middle-aged ovariectomized rats. Ten-month-old bilaterally ovariectomized (OVX) female rats were randomly divided into OVX + E2 and OVX + Veh groups. After four weeks of subcutaneous injection with 17β-estradiol or a placebo, the OVX + E2 rats exhibited significantly short mean escape latency in a spatial learning task than that in the OVX + Veh rats. Using stereological methods, we did not observe significant differences in the volumes of the hippocampus and CA1 subfields between the two groups. However, using stereological methods and electron microscopy techniques, the total length of myelinated fibers and the total volumes of myelinated fibers, myelin sheaths and myelinated axons in the CA1 subfields of OVX + E2 rats were significantly 38.1%, 34.2%, 36.1% and 32.5%, respectively, higher than those in the OVX + Veh rats. After the parameters were calculated according to different diameter ranges, the estrogen replacement-induced remodeling of myelinated fibers in CA1 was mainly manifested in the myelinated fibers with a diameter of <1.0 μm. Therefore, four weeks of continuous E2 replacement improved the spatial learning capabilities of middle-aged ovariectomized rats. The E2 replacement-induced protection of spatial learning abilities might be associated with the beneficial effects of estrogen on myelinated fibers, particularly those with the diameters less than 1.0 μm, in the hippocampal CA1 region of middle-aged ovariectomized rats.
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Affiliation(s)
- Qian Xiao
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Yanmin Luo
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Fulin Lv
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Qi He
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Hong Wu
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Fenglei Chao
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Xuan Qiu
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Lei Zhang
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Yuan Gao
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Department of Geriatrics, First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Chunxia Huang
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Department of Physiology, Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Sanrong Wang
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Chunni Zhou
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Yi Zhang
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Lin Jiang
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Department of Laboratory Medicine, Key Laboratory of Diagnostic Medicine (Ministry of Education), Chongqing Medical University, Chongqing 400016, People's Republic of China
| | - Yong Tang
- Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China; Laboratory of Stem Cells and Tissue Engineering, Department of Histology and Embryology, Chongqing Medical University, Chongqing 400016, People's Republic of China.
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Pereira LM, Guimarães IM, Oliveira VE, Bastos CP, Ribeiro FM, Prado VF, Prado MA, Pereira GS. Estradiol effect on short-term object memory under hypocholinergic condition. Brain Res Bull 2018; 140:411-417. [DOI: 10.1016/j.brainresbull.2018.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 01/10/2018] [Accepted: 01/16/2018] [Indexed: 12/20/2022]
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Sbisa AM, Gogos A, van den Buuse M. Spatial working memory in the touchscreen operant platform is disrupted in female rats by ovariectomy but not estrous cycle. Neurobiol Learn Mem 2017; 144:147-154. [PMID: 28729138 DOI: 10.1016/j.nlm.2017.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 05/31/2017] [Accepted: 07/15/2017] [Indexed: 12/12/2022]
Abstract
Learning and memory deficits have been described in rats and mice after ovariectomy (OVX) and across the estrous cycle. Preclinical researchers therefore often avoid using female animals and, consequently, a large male bias exists in the preclinical cognitive literature. In the present study we examined the role of sex hormones in the touchscreen operant platform using the spatial working memory trial unique nonmatching-to-location (TUNL) task. Twenty-nine Long Evans rats were trained to acquire the TUNL task including three incremental spatial separations (S0, S1, S2). Following 20 consecutive days of training, subjects in experiment 1 (n=15) remained intact and immediately progressed to TUNL testing, while subjects in experiment 2 were OVX (n=6) or sham-operated (n=8) prior to testing. Subjects were tested on 4 spatial separations (S0-3) with a 1s or 6s delay between the sample and nonmatching stimuli. The estrous cycle of intact rats was monitored during the 4weeks of testing. The estrous cycle phase did not significantly affect performance. In contrast, compared to intact rats, OVX impaired performance at larger spatial separations (S2-3) during the 1s delay condition. Further, during the 6s delay, OVX impaired S2 performance, however not S3. Our results suggest a probable shift in cognitive strategy following OVX, when tested with a large and novel spatial separation. Our findings suggest that ovarian hormone deprivation following OVX, but not estrous cycle, impairs spatial working memory as measured by the TUNL task. This research is relevant for future studies utilising the touchscreen TUNL task and for cognitive testing of female rats.
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Affiliation(s)
- Alyssa M Sbisa
- Hormones in Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Victoria, Australia; School of Psychology and Public Health, La Trobe University, Bundoora, Victoria, Australia
| | - Andrea Gogos
- Hormones in Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Victoria, Australia
| | - Maarten van den Buuse
- School of Psychology and Public Health, La Trobe University, Bundoora, Victoria, Australia; Department of Pharmacology, University of Melbourne, Victoria, Australia; The College of Public Health, Medical and Veterinary Sciences, James Cook University, Queensland, Australia.
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9
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Komine C, Nakajima S, Kondo Y, Horii Y, Yoshida M, Kawaguchi M. Effects of neonatal 17α-ethinyloestradiol exposure on female-paced mating behaviour in the rat. J Appl Toxicol 2017; 37:996-1003. [PMID: 28176338 DOI: 10.1002/jat.3449] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 12/20/2022]
Abstract
Correct perinatal oestrogen levels are critical for sexual differentiation. For example, perinatal exposure to oestrogen causes masculinization and defeminization of the brain in female rats and also induces delayed effects after maturation characterized by early onset of abnormal oestrus cycling. However, the mechanisms underlying the above effects of oestrogen remain to be fully determined. 17α-ethinyloestradiol (EE), a common synthetic oestrogen widely used in oral contraceptives, binds specifically to oestrogen receptors. In this study, we demonstrated the effects of a single neonatal injection of high- or low-dose EE on reproductive behaviours. Female rats within 24 h after birth were subcutaneously injected with sesame oil, EE (0.02, 2 mg kg-1 ) and 17β-oestradiol (E2 ) (20 mg kg-1 ). Between 11 and 15 weeks of age, sexual behaviour was tested twice in a paced mating situation. Latency to enter, lordosis and soliciting behaviour were recorded. Both high-dose EE- and E2 -treated females showed a significantly lower lordosis quotient, decreased soliciting behaviours, increased rejection and fighting numbers. Accessibility to males was also delayed by neonatal E2 exposure, although it was shortened by high-dose EE exposure. In contrast, low-dose EE-treated females did not exhibit impaired sexual behaviour. These results suggest that single neonatal exposure to a high dose of EE or E2 disturbs the normal development of the female brain, resulting in impaired sexual behaviours in a female-paced mating situation. Besides, the differences noted between high-dose EE- and E2 -treated females might be caused by different affinities of the oestrogen receptors, metabolic rates or mechanisms of action. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Chiaki Komine
- Laboratory of Animal Behavior and Environmental Science, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Shingo Nakajima
- Laboratory of Animal Behavior and Environmental Science, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Yasuhiko Kondo
- Department of Animal Sciences, Teikyo University of Science, 2-2-1 Senju-Sakuragi, Adachi-ku, Tokyo, Japan
| | - Yasuyuki Horii
- Laboratory of Animal Behavior and Environmental Science, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Midori Yoshida
- National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, Japan
| | - Maiko Kawaguchi
- Laboratory of Animal Behavior and Environmental Science, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
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