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MacLusky NJ, Thomas G, Leranth C. Low dietary soy isoflavonoids increase hippocampal spine synapse density in ovariectomized rats. Brain Res 2017; 1657:361-367. [PMID: 28063855 DOI: 10.1016/j.brainres.2017.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/21/2016] [Accepted: 01/01/2017] [Indexed: 01/14/2023]
Abstract
High dietary intake of plant estrogens (phytoestrogens) can affect brain structure and function. The effects of phytoestrogen intake within the range of normal animal and human dietary consumption, however, remain uncertain. The aim of the present study was to determine the effects of the isoflavonoids present in a standard low phytoestrogen laboratory rat chow on spine synapse density in the stratum radiatum of area CA1 of the hippocampus. Weanling rats (22days old) were fed either standard chow (Teklad 2018), a nutritionally comparable diet without soy (Teklad 2016) or a custom diet containing Teklad 2016 supplemented with the principal soy isoflavonoids, daidzein and genistein, for 40days. Rats were ovariectomized at 54days of age. Eight days later, spine synapse density on the apical dendrites of hippocampal pyramidal neurons in the stratum radiatum of area CA1 was measured by electron microscopic stereological analysis. Animals maintained on Teklad 2016 exhibited an approximately 60% lower CA1 spine synapse density than animals consuming Teklad 2018. Replacing genistein and daidzein in Teklad 2016 returned synapse density to levels indistinguishable from those in animals on Teklad 2018. These results indicate that the isoflavonoids in a standard laboratory rat diet exert significant effects on spine synapse density in the CA1 region of the hippocampus. Since changes in spine synapse density in this region of the hippocampus have been linked to cognitive performance and mood state, these data suggest that even relatively low daily consumption of soy phytoestrogens may be sufficient to influence hippocampal function.
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Affiliation(s)
- Neil J MacLusky
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
| | - Gladis Thomas
- Departments of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06520-8063, USA
| | - Csaba Leranth
- Departments of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06520-8063, USA; Neurobiology, Yale University School of Medicine, New Haven, CT 06520-8063, USA
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Peña CJ, Neugut YD, Champagne FA. Developmental timing of the effects of maternal care on gene expression and epigenetic regulation of hormone receptor levels in female rats. Endocrinology 2013; 154:4340-51. [PMID: 24002038 PMCID: PMC3800762 DOI: 10.1210/en.2013-1595] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Maternal care experienced during postnatal development has enduring effects on neuroendocrine function and behavior. Previous studies in rats have illustrated the effect of maternal licking/grooming (LG) on hormone receptors and maternal behavior of adult female offspring associated with altered DNA methylation. However, the developmental timing of these effects, which provide insight into the cellular and molecular pathways through which early experience alters later behavior, had not been explored. Here, we demonstrate the developmental emergence of these outcomes and use cross-fostering to identify sensitive periods for these effects. Estrogen receptor (ER)α and ERβ mRNA levels within the medial preoptic area (MPOA) of the hypothalamus were increased by postnatal day (PN)21 in female offspring of high LG dams; LG-associated increases in oxytocin receptor mRNA levels were observed beyond the weaning period. Quantification of ERα-immunoreactivity indicated a high degree of neuroanatomical specificity of LG effects within the MPOA that were observed by PN6. Reduced DNA methylation and histone 3 lysine 9 tri-methylation and increased histone 3 lysine 4 tri-methylation at the ERα gene promoter (Esr1) were detected at PN21 in high LG female offspring. Latency to engage in maternal behavior toward donor pups was significantly shorter among high LG females. Cross-fostering revealed that maternal sensitization and MPOA ERα levels are sensitive to maternal care experienced before but not after PN10. Differential windows of plasticity were identified for ERβ and oxytocin receptor mRNA levels. These studies contribute significantly to our understanding of the molecular, neurobiological, and behavioral pathways through which variation in maternal behavior is transmitted from one generation to the next.
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Affiliation(s)
- Catherine Jensen Peña
- Department of Psychology, Columbia University, 406 Schermerhorn Hall, 1190 Amsterdam Avenue, New York, New York 10027.
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Field EF, Pellis SM. The brain as the engine of sex differences in the organization of movement in rats. ARCHIVES OF SEXUAL BEHAVIOR 2008; 37:30-42. [PMID: 18074218 DOI: 10.1007/s10508-007-9270-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Sex differences in the kinematic organization of non-reproductive behavior are often relegated to byproducts of sex differences in body morphology. We review evidence showing not only that male and female rats organize their posture and stepping differently during a variety of actions, but that these differences arise from sex differences in the organization of movement in the central nervous system (CNS). Indeed, the expression and choice of sex-typical patterns of movement can be altered by CNS injury. The pattern of hormonal regulation of these sex differences is also not organized as commonly held theory would predict. As expected, males castrated shortly after birth are female-typical in their motor organization. Females ovariectomized at birth, however, are male-typical in their patterns of movement. Thus, female-typical patterns of movement organization are not the default form, but rather are dependent on the effects of gonadal steroids to feminize the developing CNS. The implications of these findings are discussed with regards to our understanding of the evolution of sex differences in CNS anatomy and behavior both for animals and humans.
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Affiliation(s)
- Evelyn F Field
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada.
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Edinger KL, Frye CA. Testosterone's anti-anxiety and analgesic effects may be due in part to actions of its 5alpha-reduced metabolites in the hippocampus. Psychoneuroendocrinology 2005; 30:418-30. [PMID: 15721054 DOI: 10.1016/j.psyneuen.2004.11.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Revised: 09/23/2004] [Accepted: 11/05/2004] [Indexed: 11/29/2022]
Abstract
Although testosterone (T) may have effects to enhance analgesia and reduce anxiety, its effects and mechanisms are not well understood. We hypothesized that if T's anti-anxiety and analgesic effects are due in part to actions of its 5alpha-reduced metabolite (dihydrotestosterone-DHT) and/or its 3alpha-hydroxysteroid dehydrogenase reduced metabolite (3alpha-androstanediol-3alpha-diol), in the hippocampus, then androgen regimens that increase levels of these metabolites in the hippocampus should produce anti-anxiety behavior, and analgesic effects, in gonadectomized (GDX) male rats. In Experiment 1, GDX rats were administered T, DHT, 3alpha-diol (1 mg/kg, SC), or vehicle. In Experiment 2, GDX rats had T, DHT, 3alpha-diol-containing inserts, or empty control inserts applied to the dorsal hippocampus immediately prior to behavioral testing. Androgen-administered rats (SC or intrahippocampal) showed significantly more exploratory behavior in the open field and elevated plus maze, less freezing in response to shock, and longer tailflick and pawlick latencies. These findings suggest that T's anti-anxiety effects may be due in part to actions of its 5alpha-reduced metabolites in the dorsal hippocampus.
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Affiliation(s)
- Kassandra L Edinger
- Department of Psychology, The University at Albany-SUNY, 1400 Washington Avenue, Albany, NY 12222, USA
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Scallet AC, Muskhelishvili L, Slikker W, Kadlubar FF. Sex differences in cytochrome P450 1B1, an estrogen-metabolizing enzyme, in the rhesus monkey telencephalon. J Chem Neuroanat 2005; 29:71-80. [PMID: 15589702 DOI: 10.1016/j.jchemneu.2004.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Revised: 09/21/2004] [Accepted: 09/23/2004] [Indexed: 11/27/2022]
Abstract
The metabolic enzyme CYP1B1 is a recently cloned member of the cytochrome P450 superfamily, expressed widely throughout primate tissue, including the CNS. Although CYP1B1 protein is known to metabolize estradiol to catecholestrogens in the uterus, its localization and function in brain have not yet been described. To better understand CYP1B1 distribution, we have combined in situ hybridization (ISH) for its mRNA with immunohistochemistry (IHC) for the CYP1B1 protein in selected brain regions of male and female adult rhesus monkeys (Macaca mulatta). Blocks of formalin-fixed tissue obtained from the frontal cortex, hippocampus, thalamus, and amygdala were processed and embedded in paraffin. They were then sectioned and stained as described for human tissue [Muskhelishvili, L., Thompson, P.A., Kusewitt, D.F., Wang, C., Kadlubar, F.F., 2001. In situ hybridization and immunohistochemical analysis of cytochrome P450 1B1 expression in human normal tissues. J. Histochem. Cytochem. 49, 229-236]. Results indicated widespread distribution of CYP1B1 mRNA in both male and female monkey frontal cortex, hippocampus, thalamus, and amygdala. In contrast, although CYP1B1 protein was co-localized with its mRNA in the female brains, it was primarily restricted to hippocampal pyramidal neurons in the male brains. These results suggest that CYP1B1 may subserve widespread metabolic functions in the female primate brain but have more restricted actions within the hippocampal pyramidal neurons of the male.
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Affiliation(s)
- Andrew C Scallet
- Division of Neurotoxicology, National Center for Toxicological Research, NCTR/FDA, 3900 NCTR Drive, Jefferson, AR 72079, USA.
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Field EF, Whishaw IQ, Forgie ML, Pellis SM. Neonatal and pubertal, but not adult, ovarian steroids are necessary for the development of female-typical patterns of dodging to protect a food item. Behav Neurosci 2005; 118:1293-304. [PMID: 15598138 DOI: 10.1037/0735-7044.118.6.1293] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Rats protect food by dodging horizontally away from a conspecific. Females and males use different movement and stepping patterns to execute a dodge. An unresolved question is whether exposure to ovarian steroids in females is necessary for the development of the female-typical pattern. Females ovariectomized neonatally and prior to puberty use a combination of male and female tactics. Pregnant females, however, use a female-typical pattern of dodging, suggesting that the patterns used by prepubertal ovariectomized females are not due to their increase in body mass. Thus, the contribution of ovarian steroids to the development of female-typical patterns of behavior needs to be studied further at both a behavioral and neural level with regard to the organization of movement.
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Affiliation(s)
- Evelyn F Field
- Department of Psychology and Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada.
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Abstract
Perimenopause is characterized by decreasing levels of estrogens and progesterone until gonadal secretion comes to a complete halt. There are still very different views and positions on the significance of the menopause. Physical, mental-vegetative and depressive symptoms during climacteric are different in each culture. Currently, there is some controversy as to whether or not there really is a rise in actual depression during the perimenopausal phase of woman's life. The observations from humans taken together indicate that depressive disorders, as defined in ICD-10, do not occur more frequently during perimenopause. In this context, the terms subthreshold depression and or subsyndromal depression are important, describing depressive symptoms which do not fulfil the complete clinical picture of a depressive episode, either because there are not enough symptoms or because they are not severe enough. The affected women still suffer, but until now not enough studies have been carried out on this particular area. In view of the complexity and relevance of the perimenopausal period in a woman's life, it is necessary to establish and maintain a network of treatment between the family physician, gynecologist, psychiatrist and or psychotherapist, as soon as significant depressive symptoms occur.
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Affiliation(s)
- M Banger
- Department of Psychiatry, University of Essen, Virchowstrasse 174, 45147, Essen, Germany.
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McEwen BS. Invited review: Estrogens effects on the brain: multiple sites and molecular mechanisms. J Appl Physiol (1985) 2001; 91:2785-801. [PMID: 11717247 DOI: 10.1152/jappl.2001.91.6.2785] [Citation(s) in RCA: 473] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Besides their well-established actions on reproductive functions, estrogens exert a variety of actions on many regions of the nervous system that influence higher cognitive function, pain mechanisms, fine motor skills, mood, and susceptibility to seizures; they also appear to have neuroprotective actions in relation to stroke damage and Alzheimer's disease. Estrogen actions are now recognized to occur via two different intracellular estrogen receptors, ER-alpha and ER-beta, that reside in the cell nuclei of some nerve cells, as well as by some less well-characterized mechanisms. In the hippocampus, such nerve cells are sparse in number and yet appear to exert a powerful influence on synapse formation by neurons that do not have high levels of nuclear estrogen receptors. However, we also find nonnuclear estrogen receptors outside of the cell nuclei in dendrites, presynaptic terminals, and glial cells, where estrogen receptors may couple to second messenger systems to regulate a variety of cellular events and signal to the nuclear via transcriptional regulators such as CREB. Sex differences exist in many of the actions of estrogens in the brain, and the process of sexual differentiation appears to affect many brain regions outside of the traditional brain areas involved in reproductive functions. Finally, the aging brain is responsive to actions of estrogens, which have neuroprotective effects both in vivo and in vitro. However, in an animal model, the actions of estrogens on the hippocampus appear to be somewhat attenuated with age. In the future, estrogen actions over puberty and in pregnancy and lactation should be further explored and should be studied in both the hypothalamus and the extrahypothalamic regions.
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Affiliation(s)
- B S McEwen
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, Rockefeller University, 1230 York Ave., New York, NY 10021, USA.
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Hohmann CF, Wallace SA, Johnston MV, Blue ME. Effects of neonatal cholinergic basal forebrain lesions on excitatory amino acid receptors in neocortex. Int J Dev Neurosci 1998; 16:645-60. [PMID: 10198813 DOI: 10.1016/s0736-5748(98)00075-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The role of cholinergic basal forebrain projections in the modulation of cortical plasticity and associated functional changes is currently the subject of renewed attention. Excitatory amino acid receptors have been identified as mediators of cortical topographic efferent and afferent information. In addition some of these receptors, notably the NMDA and metabotropic [mGluR] type, participate in cortical plasticity. Growing evidence suggests that interactions between cholinergic and glutamatergic systems contribute to cognitive cortical functions and their anatomical and physiological substrates. Though cholinergic and glutamatergic mechanisms have both been shown to be involved in cortical morphogenesis, few studies have attempted to study their interactions in development. The present study investigates the effect of neonatal lesions to the cholinergic basal forebrain on NMDA, AMPA and mGluR receptors in BALB/CByJ mice, at two different developmental ages. We demonstrated previously that nBM lesions at birth result in transient cholinergic depletion for the first two postnatal weeks, substantial morphogenetic alterations in neocortex and cognitive deficits by adulthood. We show here that unilateral neonatal lesions result in decreases in NMDA and AMPA receptors but increases in mGluRs during the second postnatal week (PND 14). At 30 days postnatal, lesion mediated changes were attenuated, compared with PND 14, but significant sex differences in control and nBM lesioned mice were apparent. These data support the notion that cholinergic/glutamatergic interactions are important during early cortical morphogenesis. Moreover, our results highlight the fact that cholinergic as well glutamatergic developmental mechanisms are sexually dimorphic.
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Affiliation(s)
- C F Hohmann
- Morgan State University, Baltimore, MD 21251, USA.
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MacLusky NJ, Bowlby DA, Brown TJ, Peterson RE, Hochberg RB. Sex and the developing brain: suppression of neuronal estrogen sensitivity by developmental androgen exposure. Neurochem Res 1997; 22:1395-414. [PMID: 9355112 DOI: 10.1023/a:1022027408234] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The developmental effects of androgen play a central role in sexual differentiation of the mammalian central nervous system. The cellular mechanisms responsible for mediating these effects remain incompletely understood. A considerable amount of evidence has accumulated indicating that one of the earliest detectable events in the mechanism of sexual differentiation is a selective and permanent reduction in estrogen receptor concentrations in specific regions of the brain. Using quantitative autoradiographic methods, it has been possible to precisely map the regional distribution of estrogen receptors in the brains of male and female rats, as well as to study the development of sexual dimorphisms in receptor distribution. Despite previous data suggesting that the left and right sides of the brain may be differentially responsive to early androgen exposure, there is no significant right-left asymmetry in estrogen receptor distribution, in either sex. Significant sex differences in receptor density are, however, observed in several regions of the preoptic area, the bed nucleus of the stria terminalis and the ventromedial nucleus of the hypothalamus, particularly in its most rostral and caudal aspects. In the periventricular preoptic area of the female, highest estrogen receptor density occurs in the anteroventral periventricular region: binding in this region is reduced by approximately 50% in the male, as compared to the female. These data are consistent with the hypothesis that androgen-induced defeminization of feminine behavioral and neuroendocrine responses to estrogen may involve selective reductions in the estrogen sensitivity of critical components of the neural circuitry regulating these responses, mediated in part through a reduction in estrogen receptor biosynthesis.
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Affiliation(s)
- N J MacLusky
- Division of Reproductive Science, Toronto Hospital Research Institute, Ontario, Canada
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Brown TJ, Sharma M, Heisler LE, Karsan N, Walters MJ, MacLusky NJ. In vitro labeling of gonadal steroid hormone receptors in brain tissue sections. Steroids 1995; 60:726-37. [PMID: 8585096 DOI: 10.1016/0039-128x(95)00107-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Autoradiographic methods have been developed for measurement of gonadal steroid receptors in situ in brain tissue sections. Based on principles established previously for estrogen receptors in the rat brain using a 125I-labeled ligand, procedures have been developed for in vitro labeling of estrogen, androgen, and progestin receptors with commercially available tritiated ligands. Addition of protamine sulfate to the incubation buffer precipitates the receptors in situ in the tissue sections, allowing them to be detected autoradiographically after incubation with labeled steroid and subsequent washing to remove unbound and nonspecifically bound ligand. Occupied and unoccupied estrogen receptors can be measured selectively using appropriately modified incubation conditions. In the case of androgen and progestin receptors, unoccupied receptors are readily detected by in vitro labeling of tissue sections, but occupied receptors do not appear to label efficiently. Preliminary data suggest that these methods should be equally applicable to a variety of laboratory animals, including the rat, mouse, guinea pig, and monkey.
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MESH Headings
- Animals
- Autoradiography/methods
- Brain Chemistry
- Estradiol/chemistry
- Estradiol/metabolism
- Female
- Guinea Pigs
- Haplorhini
- In Vitro Techniques
- Ligands
- Male
- Metribolone/chemistry
- Metribolone/metabolism
- Mice
- Mice, Inbred ICR
- Promegestone/analogs & derivatives
- Promegestone/chemistry
- Promegestone/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Androgen/analysis
- Receptors, Androgen/chemistry
- Receptors, Androgen/metabolism
- Receptors, Estrogen/analysis
- Receptors, Estrogen/chemistry
- Receptors, Estrogen/metabolism
- Receptors, Progesterone/analysis
- Receptors, Progesterone/chemistry
- Receptors, Progesterone/metabolism
- Receptors, Steroid/analysis
- Receptors, Steroid/chemistry
- Receptors, Steroid/metabolism
- Reproducibility of Results
- Tritium
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Affiliation(s)
- T J Brown
- Department of Obstetrics and Gynecology, University of Toronto, Ontario, Canada
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